Count Babel tests towards Babylon code coverage (#182)

* Add code coverage from Babel tests

* Configure nyc correctly for Babel test coverage

* Guard against nyc config conflicts if Babel switches to nyc in the future

* Move .nyc_output from Babel build dir to root

.travis.yml

@@ -35,7 +35,7 @@ matrix:
     - node_js: "node"
       env: BABEL=true
 
-after_success: 'if [ -z "${LINT-}" ] && [ -z "${FLOW-}" ] && [ -z "${BABEL-}" ]; then npm run coverage ; fi'
+after_success: 'if [ -z "${LINT-}" ] && [ -z "${FLOW-}" ]; then npm run coverage ; fi'
 
 notifications:
   slack: babeljs:5Wy4QX13KVkGy9CnU0rmvgeK

Makefile

@@ -14,7 +14,10 @@ bootstrap-babel: clean
 	find ./build/babel/packages -type d -name 'babylon' -prune -exec rm -rf '{}' \; -exec ln -s '../../../../../' '{}' \;
 
 test-babel:
-	npm run build
+	BABEL_ENV=test npm run build
+	# in case babel ever switches to nyc: filter its config out of package.json
 	cd ./build/babel; \
-	make test-only
-
+	jq "del(.nyc)" package.json > package.nonyc.json; \
+	mv -f package.nonyc.json package.json; \
+	../../node_modules/.bin/nyc --no-instrument --no-source-map --report-dir ../../coverage node_modules/mocha/bin/_mocha `scripts/_get-test-directories.sh` --opts test/mocha.opts; \
+	mv .nyc_output ../../.nyc_output