diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 7259149149..4d38b69a5e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -115,6 +115,12 @@ Use the `TEST_GREP` variable to run a subset of tests by name:
 $ TEST_GREP=transformation make test
 ```
 
+To enable the node debugger added in v6.3.0, set the `TEST_DEBUG` environment variable:
+
+```sh
+$ TEST_DEBUG=true make test
+```
+
 To test the code coverage, use:
 
 ```sh
diff --git a/scripts/test.sh b/scripts/test.sh
index c817012d50..e9893371da 100755
--- a/scripts/test.sh
+++ b/scripts/test.sh
@@ -5,4 +5,10 @@ if [ -z "$TEST_GREP" ]; then
    TEST_GREP=""
 fi
 
-node node_modules/mocha/bin/_mocha `scripts/_get-test-directories.sh` --opts test/mocha.opts --grep "$TEST_GREP"
+node="node"
+
+if [ "$TEST_DEBUG" ]; then
+   node="node --inspect --debug-brk"
+fi
+
+$node node_modules/mocha/bin/_mocha `scripts/_get-test-directories.sh` --opts test/mocha.opts --grep "$TEST_GREP"