diff --git a/packages/babel-helper-transform-fixture-test-runner/src/index.js b/packages/babel-helper-transform-fixture-test-runner/src/index.js
index bf1f93f137..fde5f91326 100644
--- a/packages/babel-helper-transform-fixture-test-runner/src/index.js
+++ b/packages/babel-helper-transform-fixture-test-runner/src/index.js
@@ -28,17 +28,6 @@ const testContext = vm.createContext({
 });
 testContext.global = testContext;
 
-// Add chai's assert to the global context
-// It has to be required inside the testContext as otherwise some assertions do not
-// work as chai would reference globals (RegExp, Array, ...) from this context
-vm.runInContext(
-  "(function(require) { global.assert=require('chai').assert; });",
-  testContext,
-  {
-    displayErrors: true,
-  },
-)(id => runModuleInTestContext(id, __filename));
-
 // Initialize the test context with the polyfill, and then freeze the global to prevent implicit
 // global creation in tests, which could cause things to bleed between tests.
 runModuleInTestContext("@babel/polyfill", __filename);
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/exec.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/exec.js
index 5a2a7dab94..344a21c755 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/exec.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/exec.js
@@ -19,4 +19,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello, 'hello');
+expect(new Outer().hello).toBe('hello');
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/input.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/input.js
index 5a2a7dab94..344a21c755 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/input.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/input.js
@@ -19,4 +19,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello, 'hello');
+expect(new Outer().hello).toBe('hello');
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/output.js
index e94ddfeba6..f7f591a606 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-call-in-key/output.js
@@ -38,4 +38,4 @@ function (_Hello) {
   return Outer;
 }(Hello);
 
-assert.equal(new Outer().hello, 'hello');
+expect(new Outer().hello).toBe('hello');
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/exec.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/exec.js
index 7359814f19..5e0087f891 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/exec.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/exec.js
@@ -16,4 +16,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello, 'hello');
+expect(new Outer().hello).toBe('hello');
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/input.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/input.js
index 7359814f19..5e0087f891 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/input.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/input.js
@@ -16,4 +16,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello, 'hello');
+expect(new Outer().hello).toBe('hello');
diff --git a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/output.js b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/output.js
index 0aa59affa5..58d0250eb2 100644
--- a/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/output.js
+++ b/packages/babel-plugin-proposal-class-properties/test/fixtures/nested-class/super-property-in-key/output.js
@@ -45,4 +45,4 @@ function (_Hello) {
   return Outer;
 }(Hello);
 
-assert.equal(new Outer().hello, 'hello');
+expect(new Outer().hello).toBe('hello');
diff --git a/packages/babel-plugin-proposal-optional-catch-binding/test/fixtures/optional-catch-bindings/exec.js b/packages/babel-plugin-proposal-optional-catch-binding/test/fixtures/optional-catch-bindings/exec.js
index c55bbe53ac..ed44a1b315 100644
--- a/packages/babel-plugin-proposal-optional-catch-binding/test/fixtures/optional-catch-bindings/exec.js
+++ b/packages/babel-plugin-proposal-optional-catch-binding/test/fixtures/optional-catch-bindings/exec.js
@@ -6,7 +6,7 @@ const test = () => {
     return true;
   }
 }
-assert(test());
+expect(test()).toBe(true);
 
 const test2 = () => {
   try {
@@ -16,4 +16,4 @@ const test2 = () => {
     return true;
   }
 }
-assert(test2());
+expect(test2()).toBe(true);
diff --git a/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/duplicate-function-scope.js b/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/duplicate-function-scope.js
index 3fd573afb4..f4f4d792f1 100644
--- a/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/duplicate-function-scope.js
+++ b/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/duplicate-function-scope.js
@@ -7,4 +7,4 @@ function test () {
   }();
 }
 
-assert(test(), "inner");
+expect(test()).toBe("inner");
diff --git a/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/for-continuation-outer-reference.js b/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/for-continuation-outer-reference.js
index 16a171d571..f4485243fe 100644
--- a/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/for-continuation-outer-reference.js
+++ b/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/for-continuation-outer-reference.js
@@ -10,4 +10,4 @@ for (let index = 0; index < data.length; index++) {
     let fn = function () {item;};
 }
 
-assert(data.every(item => item));
+expect(data.every(item => item)).toBe(true);
diff --git a/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/scope-bindings.js b/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/scope-bindings.js
index 9d9e2f634b..877467f94c 100644
--- a/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/scope-bindings.js
+++ b/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/scope-bindings.js
@@ -13,12 +13,12 @@ var res = transform(code, {
           Scope: {
             exit: function(path) {
               if (innerScope) {
-                assert(Object.keys(path.scope.bindings).length === 0, 'Inner scope should not have any bindings');
+                expect(Object.keys(path.scope.bindings)).toHaveLength(0);
                 innerScope = false;
                 return;
               }
 
-              assert(Object.keys(path.scope.bindings).length === 2, 'Outer scope subsume the inner-scope binding');
+              expect(Object.keys(path.scope.bindings)).toHaveLength(2);
             }
           }
         }
diff --git a/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/switch-break.js b/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/switch-break.js
index baeaa30410..ac8eff3b95 100644
--- a/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/switch-break.js
+++ b/packages/babel-plugin-transform-block-scoping/test/fixtures/exec/switch-break.js
@@ -2,7 +2,7 @@ if (true) {
   const x = 1;
   switch (x) {
     case 1: {
-      assert(x, 1);
+      expect(x).toBe(1);
       break;
     }
   }
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/exec.js
index 7449b0aa90..b68b503253 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/exec.js
@@ -19,5 +19,5 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/input.js
index c8bd42f157..1abe3f6b7f 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/input.js
@@ -11,5 +11,5 @@ class Obj extends Base {
 Obj.prototype.test = 2;
 
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/output.js
index ee9b5419da..943986b2af 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-data-defined-on-parent/output.js
@@ -49,5 +49,5 @@ function (_Base) {
 
 Obj.prototype.test = 2;
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/exec.js
index 78335607a8..447e3be5b4 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/exec.js
@@ -1,7 +1,7 @@
 "use strict";
 class Base {
   get test() {
-    assert.equal(this, obj);
+    expect(this).toBe(obj);
     return 1;
   }
 }
@@ -18,5 +18,5 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/input.js
index 78335607a8..447e3be5b4 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/input.js
@@ -1,7 +1,7 @@
 "use strict";
 class Base {
   get test() {
-    assert.equal(this, obj);
+    expect(this).toBe(obj);
     return 1;
   }
 }
@@ -18,5 +18,5 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/output.js
index f643c30c55..a681a705b3 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-getter-defined-on-parent/output.js
@@ -30,7 +30,7 @@ function () {
   _createClass(Base, [{
     key: "test",
     get: function () {
-      assert.equal(this, obj);
+      expect(this).toBe(obj);
       return 1;
     }
   }]);
@@ -65,5 +65,5 @@ Object.defineProperty(Obj.prototype, 'test', {
   configurable: true
 });
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/exec.js
index ad8535bcf5..ad5dc5806d 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/exec.js
@@ -14,5 +14,5 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/input.js
index ad8535bcf5..ad5dc5806d 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/input.js
@@ -14,5 +14,5 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/output.js
index c9d5f68271..1a06ef6e3e 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-not-defined-on-parent/output.js
@@ -51,5 +51,5 @@ Object.defineProperty(Obj.prototype, 'test', {
   configurable: true
 });
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/exec.js
index 949bd5d3a1..94d8d54a9c 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/exec.js
@@ -17,5 +17,5 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/input.js
index 949bd5d3a1..94d8d54a9c 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/input.js
@@ -17,5 +17,5 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/output.js
index 21c8294157..0fc82313c9 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/get-semantics-setter-defined-on-parent/output.js
@@ -64,5 +64,5 @@ Object.defineProperty(Obj.prototype, 'test', {
   configurable: true
 });
 const obj = new Obj();
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/exec.js
index 27ffb6e936..c92b28377e 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/exec.js
@@ -19,7 +19,7 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, 1);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBe(1);
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/input.js
index 27ffb6e936..c92b28377e 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/input.js
@@ -19,7 +19,7 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, 1);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBe(1);
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/output.js
index 2774c53748..1daf470d4e 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-data-defined-on-parent/output.js
@@ -61,7 +61,7 @@ Object.defineProperty(Obj.prototype, 'test', {
   configurable: true
 });
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, 1);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBe(1);
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/exec.js
index 3529d7b593..6dcdc143c8 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/exec.js
@@ -19,10 +19,10 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.throws(() => {
+expect(() => {
   obj.set();
-});
-assert.equal(called, false);
-assert.equal(Base.prototype.test, 1);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 2);
+}).toThrow();
+expect(called).toBe(false);
+expect(Base.prototype.test).toBe(1);
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/input.js
index 7952ae5bf5..13b2b9be43 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/input.js
@@ -17,11 +17,11 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.throws(() => {
+expect(() => {
   // this requires helpers to be in file (not external), so they
   // are in "strict" mode code.
   obj.set();
-});
-assert.equal(Base.prototype.test, 1);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 2);
+}).toThrow();
+expect(Base.prototype.test).toBe(1);
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/output.js
index 974e8a2aff..c8a26ebfd5 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-getter-defined-on-parent/output.js
@@ -70,11 +70,11 @@ Object.defineProperty(Obj.prototype, 'test', {
   configurable: true
 });
 const obj = new Obj();
-assert.throws(() => {
+expect(() => {
   // this requires helpers to be in file (not external), so they
   // are in "strict" mode code.
   obj.set();
-});
-assert.equal(Base.prototype.test, 1);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 2);
+}).toThrow();
+expect(Base.prototype.test).toBe(1);
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/exec.js
index ef14864502..5a1625194c 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/exec.js
@@ -14,7 +14,7 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/input.js
index ef14864502..5a1625194c 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/input.js
@@ -14,7 +14,7 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/output.js
index 5fb61861f3..b57fb3242a 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/output.js
@@ -55,7 +55,7 @@ Object.defineProperty(Obj.prototype, 'test', {
   configurable: true
 });
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/exec.js
index f1620fec3e..156b48ae9a 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/exec.js
@@ -14,8 +14,8 @@ class Obj extends Base {
 }
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(called, false);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(called).toBe(false);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/input.js
index 38111c8642..1eeb1bbba8 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/input.js
@@ -11,7 +11,7 @@ class Obj extends Base {
 }
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/output.js
index 969ef7af06..f257b83b8c 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/output.js
@@ -53,7 +53,7 @@ function (_Base) {
 }(Base);
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/exec.js
index 3a8f4fbdf6..bf9d73d74d 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/exec.js
@@ -9,7 +9,7 @@ class Obj extends Base {
 }
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/input.js
index 3a8f4fbdf6..bf9d73d74d 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/input.js
@@ -9,7 +9,7 @@ class Obj extends Base {
 }
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/output.js
index 699acb30d8..e9420c448f 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/output.js
@@ -50,7 +50,7 @@ function (_Base) {
 }(Base);
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/exec.js
index 16e65031fb..db94d10d58 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/exec.js
@@ -14,8 +14,8 @@ class Obj extends Base {
 }
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, undefined);
-assert.equal(value, 2);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBeUndefined();
+expect(value).toBe(2);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/input.js
index 4185c0bb0f..3c21a7ffb5 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/input.js
@@ -5,7 +5,7 @@ class Base {
 let value = 2;
 class Obj extends Base {
   set test(v) {
-    assert.equal(this, obj);
+    expect(this).toBe(obj);
     value = v;
   }
 
@@ -15,8 +15,8 @@ class Obj extends Base {
 }
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, undefined);
-assert.equal(value, 2);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBeUndefined();
+expect(value).toBe(2);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/output.js
index aaf810f5d9..fd46a3a7b7 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/output.js
@@ -49,7 +49,7 @@ function (_Base) {
   }, {
     key: "test",
     set: function (v) {
-      assert.equal(this, obj);
+      expect(this).toBe(obj);
       value = v;
     }
   }]);
@@ -58,8 +58,8 @@ function (_Base) {
 }(Base);
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, undefined);
-assert.equal(value, 2);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBeUndefined();
+expect(value).toBe(2);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/exec.js
index 97a36a3b9e..153f89d3d2 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/exec.js
@@ -18,8 +18,8 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(value, 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 2);
+expect(obj.set()).toBe(3);
+expect(value).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/input.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/input.js
index 97a36a3b9e..153f89d3d2 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/input.js
@@ -18,8 +18,8 @@ Object.defineProperty(Obj.prototype, 'test', {
 });
 
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(value, 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 2);
+expect(obj.set()).toBe(3);
+expect(value).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/output.js b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/output.js
index 4bb99004e1..a221eb568c 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/get-set/set-semantics-setter-defined-on-parent/output.js
@@ -70,8 +70,8 @@ Object.defineProperty(Obj.prototype, 'test', {
   configurable: true
 });
 const obj = new Obj();
-assert.equal(obj.set(), 3);
-assert.equal(value, 3);
-assert.equal(Base.prototype.test, undefined);
-assert.equal(Obj.prototype.test, 2);
-assert.equal(obj.test, 2);
+expect(obj.set()).toBe(3);
+expect(value).toBe(3);
+expect(Base.prototype.test).toBeUndefined();
+expect(Obj.prototype.test).toBe(2);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/exec.js
index 696f6b86e8..3da73dba03 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/exec.js
@@ -1,6 +1,6 @@
 class Point {
   getX() {
-    assert.equal(this.x, 3); // C
+    expect(this.x).toBe(3); // C
   }
 }
 
@@ -9,8 +9,8 @@ class ColorPoint extends Point {
     super();
     this.x = 2;
     super.x = 3;
-    assert.equal(this.x, 3)   // A
-    assert.equal(super.x, undefined)  // B
+    expect(this.x).toBe(3);   // A
+    expect(super.x).toBeUndefined();  // B
   }
 
   m() {
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/input.js b/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/input.js
index 46317d841c..43ef89ce6f 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/input.js
@@ -1,6 +1,6 @@
 class Point {
   getX() {
-    assert.equal(this.x, 3); // C
+    expect(this.x).toBe(3); // C
   }
 }
 
@@ -9,8 +9,8 @@ class ColorPoint extends Point {
     super();
     this.x = 2;
     super.x = 3;
-    assert.equal(this.x, 3);   // A
-    assert.equal(super.x, undefined);  // B
+    expect(this.x).toBe(3);   // A
+    expect(super.x).toBeUndefined();  // B
   }
 
   m() {
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/output.js b/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/output.js
index bb87d170a0..91beae28f9 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/regression/5769/output.js
@@ -10,7 +10,7 @@ function () {
   babelHelpers.createClass(Point, [{
     key: "getX",
     value: function getX() {
-      assert.equal(this.x, 3); // C
+      expect(this.x).toBe(3); // C
     }
   }]);
   return Point;
@@ -30,9 +30,9 @@ function (_Point) {
     _this = babelHelpers.possibleConstructorReturn(this, babelHelpers.getPrototypeOf(ColorPoint).call(this));
     _this.x = 2;
     babelHelpers.set(babelHelpers.getPrototypeOf(ColorPoint.prototype), "x", 3, _this, true)
-    assert.equal(_this.x, 3); // A
+    expect(_this.x).toBe(3); // A
 
-    assert.equal(babelHelpers.get(babelHelpers.getPrototypeOf(ColorPoint.prototype), "x", babelHelpers.assertThisInitialized(_this)), undefined); // B
+    expect(babelHelpers.get(babelHelpers.getPrototypeOf(ColorPoint.prototype), "x", babelHelpers.assertThisInitialized(_this))).toBeUndefined(); // B
 
     return _this;
   }
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/regression/5817/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/regression/5817/exec.js
index 16c12bc3c2..3eecd23c21 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/regression/5817/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/regression/5817/exec.js
@@ -13,4 +13,4 @@ class Table extends Parent {
 
 const table = new Table();
 
-assert(table.returnParam(false) === false);
+expect(table.returnParam(false)).toBe(false);
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/exec.js
index 4dcb62d99f..73868b7759 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/exec.js
@@ -21,4 +21,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/input.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/input.js
index 4dcb62d99f..73868b7759 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/input.js
@@ -21,4 +21,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/output.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/output.js
index 744cd7d4b4..eb661ef2b3 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-call-in-key/output.js
@@ -44,4 +44,4 @@ function (_Hello) {
   return Outer;
 }(Hello);
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/exec.js
index e6b8583a0b..25b5cb653b 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/exec.js
@@ -18,4 +18,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/input.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/input.js
index e6b8583a0b..25b5cb653b 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/input.js
@@ -18,4 +18,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/output.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/output.js
index 237547f2f9..50f327ba01 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-class-super-property-in-key/output.js
@@ -51,4 +51,4 @@ function (_Hello) {
   return Outer;
 }(Hello);
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/exec.js
index 2140b943f9..4569dbb45e 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/exec.js
@@ -21,4 +21,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/input.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/input.js
index 2140b943f9..4569dbb45e 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/input.js
@@ -21,4 +21,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/output.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/output.js
index 362b5cc2d4..d540908b48 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-call-in-key/output.js
@@ -31,4 +31,4 @@ function (_Hello) {
   return Outer;
 }(Hello);
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/exec.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/exec.js
index 0587f1b0f8..5064cce138 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/exec.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/exec.js
@@ -18,4 +18,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/input.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/input.js
index 0587f1b0f8..5064cce138 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/input.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/input.js
@@ -18,4 +18,4 @@ class Outer extends Hello {
   }
 }
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/output.js b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/output.js
index 1afb4897da..38f1038862 100644
--- a/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/output.js
+++ b/packages/babel-plugin-transform-classes/test/fixtures/spec/nested-object-super-property-in-key/output.js
@@ -38,4 +38,4 @@ function (_Hello) {
   return Outer;
 }(Hello);
 
-assert.equal(new Outer().hello(), 'hello');
+expect(new Outer().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-computed-properties/test/fixtures/loose/symbol/exec.js b/packages/babel-plugin-transform-computed-properties/test/fixtures/loose/symbol/exec.js
index 026f6bc6c6..563383c71f 100644
--- a/packages/babel-plugin-transform-computed-properties/test/fixtures/loose/symbol/exec.js
+++ b/packages/babel-plugin-transform-computed-properties/test/fixtures/loose/symbol/exec.js
@@ -6,5 +6,5 @@ var foo = {
   }
 };
 
-assert(foo[Symbol.iterator], "foobar")
-assert(foo[k], k)
+expect(foo[Symbol.iterator]).toBe("foobar")
+expect(foo[k]).toBe(k)
diff --git a/packages/babel-plugin-transform-computed-properties/test/fixtures/spec/symbol/exec.js b/packages/babel-plugin-transform-computed-properties/test/fixtures/spec/symbol/exec.js
index 026f6bc6c6..563383c71f 100644
--- a/packages/babel-plugin-transform-computed-properties/test/fixtures/spec/symbol/exec.js
+++ b/packages/babel-plugin-transform-computed-properties/test/fixtures/spec/symbol/exec.js
@@ -6,5 +6,5 @@ var foo = {
   }
 };
 
-assert(foo[Symbol.iterator], "foobar")
-assert(foo[k], k)
+expect(foo[Symbol.iterator]).toBe("foobar")
+expect(foo[k]).toBe(k)
diff --git a/packages/babel-plugin-transform-jscript/test/fixtures/jscript/arrow-function/exec.js b/packages/babel-plugin-transform-jscript/test/fixtures/jscript/arrow-function/exec.js
index 3605c00f82..f46b51b884 100644
--- a/packages/babel-plugin-transform-jscript/test/fixtures/jscript/arrow-function/exec.js
+++ b/packages/babel-plugin-transform-jscript/test/fixtures/jscript/arrow-function/exec.js
@@ -6,4 +6,4 @@ class MyClass {
   }
 }
 
-assert(new MyClass().test());
+expect(new MyClass().test()).toBe(true);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/exec.js
index 6ad23f339b..4a01b5e9a2 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/exec.js
@@ -12,5 +12,5 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/input.js
index 6ad23f339b..4a01b5e9a2 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/input.js
@@ -12,5 +12,5 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/output.js
index 52b278725a..d36b217085 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-data-defined-on-parent/output.js
@@ -20,5 +20,5 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/exec.js
index fc0ff00c3f..6e4b6d5078 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/exec.js
@@ -1,7 +1,7 @@
 "use strict";
 const Base = {
   get test() {
-    assert.equal(this, obj);
+    expect(this).toBe(obj);
     return 1;
   }
 };
@@ -15,5 +15,5 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/input.js
index fc0ff00c3f..6e4b6d5078 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/input.js
@@ -1,7 +1,7 @@
 "use strict";
 const Base = {
   get test() {
-    assert.equal(this, obj);
+    expect(this).toBe(obj);
     return 1;
   }
 };
@@ -15,5 +15,5 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/output.js
index deb7546f32..3145be482f 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-getter-defined-on-parent/output.js
@@ -10,7 +10,7 @@ function _getPrototypeOf(o) { _getPrototypeOf = Object.getPrototypeOf || functio
 
 const Base = {
   get test() {
-    assert.equal(this, obj);
+    expect(this).toBe(obj);
     return 1;
   }
 
@@ -24,5 +24,5 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), 1);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBe(1);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/exec.js
index 9b74c3d981..ad77f37db0 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/exec.js
@@ -11,5 +11,5 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/input.js
index 9b74c3d981..ad77f37db0 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/input.js
@@ -11,5 +11,5 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/output.js
index 15c554bc68..ffcfc54cb2 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-not-defined-on-parent/output.js
@@ -18,5 +18,5 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/exec.js
index 7a2968c477..74b5f59f94 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/exec.js
@@ -14,5 +14,5 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/input.js
index 7a2968c477..74b5f59f94 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/input.js
@@ -14,5 +14,5 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/output.js
index ff5658433f..dda72efc33 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/get-semantics-setter-defined-on-parent/output.js
@@ -23,5 +23,5 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.test, 2);
-assert.equal(obj.get(), undefined);
+expect(obj.test).toBe(2);
+expect(obj.get()).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/exec.js
index a487a7dfe6..42b6c6135d 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/exec.js
@@ -12,6 +12,6 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, 1);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBe(1);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/input.js
index 38c5048b00..934b8b98a0 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/input.js
@@ -12,6 +12,6 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, 3);
-assert.equal(obj.test, 2);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBe(3);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/output.js
index 5854ebf94a..47dd09f90d 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-defined-on-parent/output.js
@@ -24,6 +24,6 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, 3);
-assert.equal(obj.test, 2);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBe(3);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-configurable-defined-on-parent/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-configurable-defined-on-parent/exec.js
index a54326fe37..cefef1c4da 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-configurable-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-configurable-defined-on-parent/exec.js
@@ -16,6 +16,6 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, 1);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBe(1);
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-writable-defined-on-parent-loose/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-writable-defined-on-parent-loose/exec.js
index 50bfe45e48..6770661777 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-writable-defined-on-parent-loose/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-writable-defined-on-parent-loose/exec.js
@@ -15,6 +15,6 @@ var obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, 1);
-assert.equal(obj.test, 2);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBe(1);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-writable-defined-on-parent/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-writable-defined-on-parent/exec.js
index bcb739a2dc..ff835d133a 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-writable-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-data-non-writable-defined-on-parent/exec.js
@@ -16,8 +16,8 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.throws(() => {
+expect(() => {
   obj.set();
-});
-assert.equal(Base.test, 1);
-assert.equal(obj.test, 2);
+}).toThrow();
+expect(Base.test).toBe(1);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/exec.js
index f56bd917af..5a9f314f19 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/exec.js
@@ -16,9 +16,9 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.throws(() => {
+expect(() => {
   obj.set();
-});
-assert.equal(called, false);
-assert.equal(Base.test, 1);
-assert.equal(obj.test, 2);
+}).toThrow();
+expect(called).toBe(false);
+expect(Base.test).toBe(1);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/input.js
index 9bdb1d3774..60ac63391c 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/input.js
@@ -14,10 +14,10 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.throws(() => {
+expect(() => {
   // this requires helpers to be in file (not external), so they
   // are in "strict" mode code.
   obj.set();
-});
-assert.equal(Base.test, 1);
-assert.equal(obj.test, 2);
+}).toThrow();
+expect(Base.test).toBe(1);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/output.js
index d62df684e2..d6270b3d28 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-getter-defined-on-parent/output.js
@@ -27,10 +27,10 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.throws(() => {
+expect(() => {
   // this requires helpers to be in file (not external), so they
   // are in "strict" mode code.
   obj.set();
-});
-assert.equal(Base.test, 1);
-assert.equal(obj.test, 2);
+}).toThrow();
+expect(Base.test).toBe(1);
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/exec.js
index 910e985d0e..6911e5cfb4 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/exec.js
@@ -15,11 +15,11 @@ Object.defineProperty(obj, 'test', {
 });
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
 
 const desc = Object.getOwnPropertyDescriptor(obj, 'test');
-assert.equal(desc.configurable, false);
-assert.equal(desc.writable, true);
-assert.equal(desc.enumerable, true);
+expect(desc.configurable).toBe(false);
+expect(desc.writable).toBe(true);
+expect(desc.enumerable).toBe(true);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/input.js
index 910e985d0e..6911e5cfb4 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/input.js
@@ -15,11 +15,11 @@ Object.defineProperty(obj, 'test', {
 });
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
 
 const desc = Object.getOwnPropertyDescriptor(obj, 'test');
-assert.equal(desc.configurable, false);
-assert.equal(desc.writable, true);
-assert.equal(desc.enumerable, true);
+expect(desc.configurable).toBe(false);
+expect(desc.writable).toBe(true);
+expect(desc.enumerable).toBe(true);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/output.js
index 3f5ef86ac9..e7c5873c6c 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-configurable-on-obj/output.js
@@ -26,10 +26,10 @@ Object.defineProperty(obj, 'test', {
   enumerable: true
 });
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
 const desc = Object.getOwnPropertyDescriptor(obj, 'test');
-assert.equal(desc.configurable, false);
-assert.equal(desc.writable, true);
-assert.equal(desc.enumerable, true);
+expect(desc.configurable).toBe(false);
+expect(desc.writable).toBe(true);
+expect(desc.enumerable).toBe(true);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/exec.js
index 0e66ea140b..7d350c6c31 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/exec.js
@@ -15,11 +15,11 @@ Object.defineProperty(obj, 'test', {
 });
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
 
 const desc = Object.getOwnPropertyDescriptor(obj, 'test');
-assert.equal(desc.configurable, true);
-assert.equal(desc.writable, true);
-assert.equal(desc.enumerable, false);
+expect(desc.configurable).toBe(true);
+expect(desc.writable).toBe(true);
+expect(desc.enumerable).toBe(false);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/input.js
index 0e66ea140b..7d350c6c31 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/input.js
@@ -15,11 +15,11 @@ Object.defineProperty(obj, 'test', {
 });
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
 
 const desc = Object.getOwnPropertyDescriptor(obj, 'test');
-assert.equal(desc.configurable, true);
-assert.equal(desc.writable, true);
-assert.equal(desc.enumerable, false);
+expect(desc.configurable).toBe(true);
+expect(desc.writable).toBe(true);
+expect(desc.enumerable).toBe(false);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/output.js
index 7a7c4ea6ee..923319d2b6 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-enumerable-on-obj/output.js
@@ -26,10 +26,10 @@ Object.defineProperty(obj, 'test', {
   enumerable: false
 });
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
 const desc = Object.getOwnPropertyDescriptor(obj, 'test');
-assert.equal(desc.configurable, true);
-assert.equal(desc.writable, true);
-assert.equal(desc.enumerable, false);
+expect(desc.configurable).toBe(true);
+expect(desc.writable).toBe(true);
+expect(desc.enumerable).toBe(false);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj-loose/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj-loose/exec.js
index 854d2e3479..7c00a0a47d 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj-loose/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj-loose/exec.js
@@ -14,11 +14,11 @@ Object.defineProperty(obj, 'test', {
 });
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 2);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(2);
 
 const desc = Object.getOwnPropertyDescriptor(obj, 'test');
-assert.equal(desc.configurable, true);
-assert.equal(desc.writable, false);
-assert.equal(desc.enumerable, true);
+expect(desc.configurable).toBe(true);
+expect(desc.writable).toBe(false);
+expect(desc.enumerable).toBe(true);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/exec.js
index 85e376bcfe..5f150c4002 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/exec.js
@@ -15,13 +15,13 @@ Object.defineProperty(obj, 'test', {
 });
 Object.setPrototypeOf(obj, Base);
 
-assert.throws(() => {
+expect(() => {
   obj.set();
-});
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 2);
+}).toThrow();
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(2);
 
 const desc = Object.getOwnPropertyDescriptor(obj, 'test');
-assert.equal(desc.configurable, true);
-assert.equal(desc.writable, false);
-assert.equal(desc.enumerable, true);
+expect(desc.configurable).toBe(true);
+expect(desc.writable).toBe(false);
+expect(desc.enumerable).toBe(true);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/input.js
index 85e376bcfe..5f150c4002 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/input.js
@@ -15,13 +15,13 @@ Object.defineProperty(obj, 'test', {
 });
 Object.setPrototypeOf(obj, Base);
 
-assert.throws(() => {
+expect(() => {
   obj.set();
-});
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 2);
+}).toThrow();
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(2);
 
 const desc = Object.getOwnPropertyDescriptor(obj, 'test');
-assert.equal(desc.configurable, true);
-assert.equal(desc.writable, false);
-assert.equal(desc.enumerable, true);
+expect(desc.configurable).toBe(true);
+expect(desc.writable).toBe(false);
+expect(desc.enumerable).toBe(true);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/output.js
index 24636b29a5..add5b5bf7a 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-non-writable-on-obj/output.js
@@ -26,12 +26,12 @@ Object.defineProperty(obj, 'test', {
   enumerable: true
 });
 Object.setPrototypeOf(obj, Base);
-assert.throws(() => {
+expect(() => {
   obj.set();
-});
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 2);
+}).toThrow();
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(2);
 const desc = Object.getOwnPropertyDescriptor(obj, 'test');
-assert.equal(desc.configurable, true);
-assert.equal(desc.writable, false);
-assert.equal(desc.enumerable, true);
+expect(desc.configurable).toBe(true);
+expect(desc.writable).toBe(false);
+expect(desc.enumerable).toBe(true);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/exec.js
index 58cc8e0848..0d72a1619c 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/exec.js
@@ -11,6 +11,6 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/input.js
index 58cc8e0848..0d72a1619c 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/input.js
@@ -11,6 +11,6 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/output.js
index e5c3e84ddb..7046a7e8c2 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-data-on-obj/output.js
@@ -22,6 +22,6 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj-loose/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj-loose/exec.js
index c7adbe833e..dd18ea6909 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj-loose/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj-loose/exec.js
@@ -13,7 +13,7 @@ var obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(called, false);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, undefined);
+expect(obj.set()).toBe(3);
+expect(called).toBe(false);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/exec.js
index b0d9805ea9..b151bc5559 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/exec.js
@@ -14,9 +14,9 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.throws(() => {
+expect(() => {
   obj.set();
-});
-assert.equal(called, false);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, undefined);
+}).toThrow();
+expect(called).toBe(false);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/input.js
index 84ee7a2f66..29430e7a6e 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/input.js
@@ -11,10 +11,10 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.throws(() => {
+expect(() => {
   // this requires helpers to be in file (not external), so they
   // are in "strict" mode code.
   obj.set();
-});
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, undefined);
+}).toThrow();
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/output.js
index 1245437b24..874ff4476f 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-getter-on-obj/output.js
@@ -22,10 +22,10 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.throws(() => {
+expect(() => {
   // this requires helpers to be in file (not external), so they
   // are in "strict" mode code.
   obj.set();
-});
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, undefined);
+}).toThrow();
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/exec.js
index 6946ee817e..4a919cd6d4 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/exec.js
@@ -9,6 +9,6 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/input.js
index 6946ee817e..4a919cd6d4 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/input.js
@@ -9,6 +9,6 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/output.js
index 35503bb3ec..11425ac781 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-not-on-obj/output.js
@@ -20,6 +20,6 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 3);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(3);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj-loose/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj-loose/exec.js
index eb4b815197..5823ea9745 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj-loose/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj-loose/exec.js
@@ -13,7 +13,7 @@ var obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(value, 2);
-assert.equal(obj.test, undefined);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(value).toBe(2);
+expect(obj.test).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/exec.js
index 8f0e4ae727..559edd1c42 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/exec.js
@@ -14,9 +14,9 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.throws(() => {
+expect(() => {
   obj.set();
-});
-assert.equal(value, 2);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, undefined);
+}).toThrow();
+expect(value).toBe(2);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/input.js
index fd0dbaedfa..fb10e005b5 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/input.js
@@ -5,7 +5,7 @@ const Base = {
 let value = 2;
 const obj = {
   set test(v) {
-    assert.equal(this, obj);
+    expect(this).toBe(obj);
     value = v;
   },
 
@@ -15,7 +15,7 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(value, 3);
-assert.equal(obj.test, undefined);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(value).toBe(3);
+expect(obj.test).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/output.js
index 91abe82b50..254da54137 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-not-defined-on-parent-setter-on-obj/output.js
@@ -16,7 +16,7 @@ const Base = {};
 let value = 2;
 const obj = _obj = {
   set test(v) {
-    assert.equal(this, obj);
+    expect(this).toBe(obj);
     value = v;
   },
 
@@ -26,7 +26,7 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.set(), 3);
-assert.equal(Base.test, undefined);
-assert.equal(value, 3);
-assert.equal(obj.test, undefined);
+expect(obj.set()).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(value).toBe(3);
+expect(obj.test).toBeUndefined();
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/exec.js
index 515bc6e9e2..7439c2b975 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/exec.js
@@ -15,7 +15,7 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(value, 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 2);
+expect(obj.set()).toBe(3);
+expect(value).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/input.js
index 515bc6e9e2..7439c2b975 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/input.js
@@ -15,7 +15,7 @@ const obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.equal(obj.set(), 3);
-assert.equal(value, 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 2);
+expect(obj.set()).toBe(3);
+expect(value).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/output.js
index 4439094e78..00849ff67d 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/get-set/set-semantics-setter-defined-on-parent/output.js
@@ -28,7 +28,7 @@ const obj = _obj = {
 
 };
 Object.setPrototypeOf(obj, Base);
-assert.equal(obj.set(), 3);
-assert.equal(value, 3);
-assert.equal(Base.test, undefined);
-assert.equal(obj.test, 2);
+expect(obj.set()).toBe(3);
+expect(value).toBe(3);
+expect(Base.test).toBeUndefined();
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/exec.js
index f3eef218ab..693a74ca33 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/exec.js
@@ -18,4 +18,4 @@ const Outer = {
 };
 Object.setPrototypeOf(Outer, Hello);
 
-assert.equal(Outer.constructor().hello(), 'hello');
+expect(Outer.constructor().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/input.js
index f3eef218ab..693a74ca33 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/input.js
@@ -18,4 +18,4 @@ const Outer = {
 };
 Object.setPrototypeOf(Outer, Hello);
 
-assert.equal(Outer.constructor().hello(), 'hello');
+expect(Outer.constructor().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/output.js
index 1696ec25b1..db7d6c29ea 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-class-super-property-in-key/output.js
@@ -20,4 +20,4 @@ const Outer = _obj = {
   }
 };
 Object.setPrototypeOf(Outer, Hello);
-assert.equal(Outer.constructor().hello(), 'hello');
+expect(Outer.constructor().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/exec.js
index 632490b242..bd4685b712 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/exec.js
@@ -18,4 +18,4 @@ const Outer = {
 };
 Object.setPrototypeOf(Outer, Hello);
 
-assert.equal(Outer.constructor().hello(), 'hello');
+expect(Outer.constructor().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/input.js
index 632490b242..bd4685b712 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/input.js
@@ -18,4 +18,4 @@ const Outer = {
 };
 Object.setPrototypeOf(Outer, Hello);
 
-assert.equal(Outer.constructor().hello(), 'hello');
+expect(Outer.constructor().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/output.js
index c843f1582d..b728c9c1f6 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/nested-object-super-property-in-key/output.js
@@ -18,4 +18,4 @@ const Outer = _obj = {
   }
 };
 Object.setPrototypeOf(Outer, Hello);
-assert.equal(Outer.constructor().hello(), 'hello');
+expect(Outer.constructor().hello()).toBe('hello');
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/exec.js
index 000e2910e5..f3a2aeb9c0 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/exec.js
@@ -9,6 +9,6 @@ var obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.strictEqual(obj.bar(), 1);
-assert.strictEqual(Base.test, '1');
-assert.strictEqual(obj.test, 2);
+expect(obj.bar()).toBe(1);
+expect(Base.test).toBe('1');
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/input.js
index 000e2910e5..f3a2aeb9c0 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/input.js
@@ -9,6 +9,6 @@ var obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.strictEqual(obj.bar(), 1);
-assert.strictEqual(Base.test, '1');
-assert.strictEqual(obj.test, 2);
+expect(obj.bar()).toBe(1);
+expect(Base.test).toBe('1');
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/output.js
index e0a624ee19..5a20e2f846 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-postfix/output.js
@@ -11,6 +11,6 @@ var obj = _obj = {
   }
 };
 Object.setPrototypeOf(obj, Base);
-assert.strictEqual(obj.bar(), 1);
-assert.strictEqual(Base.test, '1');
-assert.strictEqual(obj.test, 2);
+expect(obj.bar()).toBe(1);
+expect(Base.test).toBe('1');
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/exec.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/exec.js
index 723f0eecda..e333ca5692 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/exec.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/exec.js
@@ -9,6 +9,6 @@ var obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.strictEqual(obj.bar(), 2);
-assert.strictEqual(Base.test, '1');
-assert.strictEqual(obj.test, 2);
+expect(obj.bar()).toBe(2);
+expect(Base.test).toBe('1');
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/input.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/input.js
index 723f0eecda..e333ca5692 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/input.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/input.js
@@ -9,6 +9,6 @@ var obj = {
 };
 Object.setPrototypeOf(obj, Base);
 
-assert.strictEqual(obj.bar(), 2);
-assert.strictEqual(Base.test, '1');
-assert.strictEqual(obj.test, 2);
+expect(obj.bar()).toBe(2);
+expect(Base.test).toBe('1');
+expect(obj.test).toBe(2);
diff --git a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/output.js b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/output.js
index ecaa02b050..89ed7a4c8f 100644
--- a/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/output.js
+++ b/packages/babel-plugin-transform-object-super/test/fixtures/object-super/super-increment-prefix/output.js
@@ -11,6 +11,6 @@ var obj = _obj = {
   }
 };
 Object.setPrototypeOf(obj, Base);
-assert.strictEqual(obj.bar(), 2);
-assert.strictEqual(Base.test, '1');
-assert.strictEqual(obj.test, 2);
+expect(obj.bar()).toBe(2);
+expect(Base.test).toBe('1');
+expect(obj.test).toBe(2);