Add a build rule for the boilerplate unit test.

Makefile

@@ -474,4 +474,4 @@ bazel-build:
 	bazel build //cmd/... //pkg/... //federation/... //plugin/... //build/... //examples/... //test/... //third_party/...
 
 bazel-test:
-	bazel test  --test_output=errors //cmd/... //pkg/... //federation/... //plugin/... //build/... //third_party/...
+	bazel test  --test_output=errors //cmd/... //pkg/... //federation/... //plugin/... //build/... //third_party/... //hack/...

hack/boilerplate/BUILD

@@ -1,3 +1,12 @@
 package(default_visibility = ["//visibility:public"])
 
 exports_files(glob(["*.txt"]))
+
+py_test(
+    name = "boilerplate_test",
+    srcs = [
+        "boilerplate_test.py",
+        "boilerplate.py",
+    ],
+    data = glob(["*.txt", "test/*"]),
+)

hack/verify-boilerplate.sh

@@ -25,22 +25,6 @@ boiler="${boilerDir}/boilerplate.py"
 
 files_need_boilerplate=($(${boiler} "$@"))
 
-# Run boilerplate.py unit tests
-unitTestOut="$(mktemp)"
-trap cleanup EXIT
-cleanup() {
-	rm "${unitTestOut}"
-}
-
-pushd "${boilerDir}" >/dev/null
-if ! python -m unittest boilerplate_test 2>"${unitTestOut}"; then
-	echo "boilerplate_test.py failed"
-	echo
-	cat "${unitTestOut}"
-	exit 1
-fi
-popd >/dev/null
-
 # Run boilerplate check
 if [[ ${#files_need_boilerplate[@]} -gt 0 ]]; then
   for file in "${files_need_boilerplate[@]}"; do