diff --git a/.istanbul.yml b/.istanbul.yml
index 7178a27ceb..5830ddb662 100644
--- a/.istanbul.yml
+++ b/.istanbul.yml
@@ -1,2 +1,3 @@
 instrumentation:
-  root: lib
+  root: .
+  excludes: "**/node_modules/**"
diff --git a/Makefile b/Makefile
index 39032e44f3..630ee35f37 100644
--- a/Makefile
+++ b/Makefile
@@ -36,7 +36,7 @@ test-browser:
 test-cov: clean
 	BABEL_ENV=test; \
 	make build
-	node $(ISTANBUL_CMD) $(MOCHA_CMD) -- test/core
+	./scripts/test-cov.sh
 
 test-travis: bootstrap lint build test
 
diff --git a/mocha.opts b/mocha.opts
new file mode 100644
index 0000000000..300bd66961
--- /dev/null
+++ b/mocha.opts
@@ -0,0 +1 @@
+--reporter dot --ui tdd
diff --git a/scripts/_get-test-directories.sh b/scripts/_get-test-directories.sh
new file mode 100755
index 0000000000..a10453a9bd
--- /dev/null
+++ b/scripts/_get-test-directories.sh
@@ -0,0 +1,16 @@
+#!/bin/sh
+set -e
+
+TEST_DIRS=""
+
+for f in packages/*; do
+  if [ -n "$TEST_ONLY" ] && [ `basename $f` != "$TEST_ONLY" ]; then
+    continue
+  fi
+
+  if [ -d "$f/test" ]; then
+    TEST_DIRS="$f/test $TEST_DIRS"
+  fi
+done
+
+echo $TEST_DIRS
diff --git a/scripts/test-cov.sh b/scripts/test-cov.sh
new file mode 100755
index 0000000000..f194787bad
--- /dev/null
+++ b/scripts/test-cov.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+set -e
+
+node node_modules/istanbul/lib/cli.js cover node_modules/mocha/bin/_mocha -- `scripts/_get-test-directories.sh` --opts mocha.opts
+test -n "`which open`" && open coverage/lcov-report/index.html
diff --git a/scripts/test.sh b/scripts/test.sh
index c834f745e9..0acc03d650 100755
--- a/scripts/test.sh
+++ b/scripts/test.sh
@@ -5,16 +5,4 @@ if [ -z "$TEST_GREP" ]; then
    TEST_GREP=""
 fi
 
-TEST_DIRS=""
-
-for f in packages/*; do
-  if [ -n "$TEST_ONLY" ] && [ `basename $f` != "$TEST_ONLY" ]; then
-    continue
-  fi
-
-  if [ -d "$f/test" ]; then
-    TEST_DIRS="$f/test $TEST_DIRS"
-  fi
-done
-
-node node_modules/mocha/bin/_mocha $TEST_DIRS --reporter dot --ui tdd --grep "$TEST_GREP"
+node node_modules/mocha/bin/_mocha `scripts/_get-test-directories.sh` --opts mocha.opts --grep "$TEST_GREP"