diff --git a/lib/6to5/transform.js b/lib/6to5/transform.js
index c5cb44a380..f99837c1d2 100644
--- a/lib/6to5/transform.js
+++ b/lib/6to5/transform.js
@@ -8,22 +8,22 @@ var transform = module.exports = function (code, opts) {
   opts = opts || {};
 
   _.defaults(opts, {
-    blacklist: [],
-    whitelist: [],
-    sourceMap: false,
-    filename:  "unknown",
-    format:    {}
+    sourceMapObject: false,
+    blacklist:       [],
+    whitelist:       [],
+    sourceMap:       false,
+    filename:        "unknown",
+    format:          {}
   });
 
-  var tree;
+  if (opts.sourceMapObject) opts.sourceMap = true;
 
-  try {
-    tree = util.parse(code);
-  } catch (err) {
-    err.message = opts.filename + ": " + err.message;
-    throw err;
-  }
+  return util.parse(opts.filename, code, function (tree) {
+    return transform._run(code, tree, opts);
+  }, true);
+};
 
+transform._run = function (code, tree, opts) {
   traverse.replace(tree, function (node) {
     if (node.type === "EmptyStatement") {
       return traverse.Delete;
@@ -60,7 +60,11 @@ var transform = module.exports = function (code, opts) {
   var result = escodegen.generate(tree, genOpts);
 
   if (genOpts.sourceMapWithCode) {
-    return result.code + "\n" + util.sourceMapToComment(result.map) + "\n";
+    if (opts.sourceMapObject) {
+      return result;
+    } else {
+      return result.code + "\n" + util.sourceMapToComment(result.map) + "\n";
+    }
   } else {
     return result + "\n";
   }
@@ -77,23 +81,21 @@ transform._runTransformer = function (transformer, tree, opts, generateUid) {
   });
 };
 
-transform.test = function (actual, expect, opts) {
-  expect = [].concat(expect).join("\n");
-  actual = [].concat(actual).join("\n");
+transform.test = function (actual, expect, opts, debug) {
 
   opts = opts || {};
   _.defaults(opts, { filename: "test" });
 
-  actual = util.parse(transform(actual, opts));
-  expect = util.parse(expect);
+  var actualCode = actual.code.trim();
+  var transformedCode = transform(actualCode, opts);
+  var actualAst = util.parse(actual.filename, transformedCode);
 
-  try {
-    assert.deepEqual(actual, expect);
-  } catch (err) {
-    actual = escodegen.generate(actual);
-    expect = escodegen.generate(expect);
-    assert.equal(actual, expect);
-  }
+  var expectCode = expect.code.trim();
+  var expectAst = util.parse(expect.filename, expectCode);
+
+  actualCode = escodegen.generate(actualAst);
+  expectCode = escodegen.generate(expectAst);
+  assert.equal(actualCode, expectCode);
 };
 
 transform.transformers = {