Fix make unit_test_race such that it fails in case of errors.

Before this, the command always succeeded, even if races were found.

I'm grepping over the output of go test -race to check if there is race because there is no other way to distinguish between a found race and a flaky test.

Makefile

@@ -61,7 +61,7 @@ unit_test_cover: build
 	godep go test $(VT_GO_PARALLEL) -cover ./go/... | misc/parse_cover.py
 
 unit_test_race: build
-	godep go test $(VT_GO_PARALLEL) -race ./go/...
+	tools/unit_test_race.sh
 
 # Run coverage and upload to coveralls.io.
 # Requires the secret COVERALLS_TOKEN env variable to be set.

tools/unit_test_race.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+# Copyright 2015, Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+temp_log_file="$(mktemp --suffix .unit_test_race.log)"
+trap '[ -f "$temp_log_file" ] && rm $temp_log_file' EXIT
+
+# Wrapper around go test -race.
+
+# This script exists because the -race test doesn't allow to distinguish
+# between a failed (e.g. flaky) unit test and a found data race.
+# Although Go 1.5 says 'exit status 66' in case of a race, it exits with 1.
+# Therefore, we manually check the output of 'go test' for data races and
+# exit with an error if one was found.
+
+# NOTE: Go binaries <1.5 had a bug which prevented go test -race from exiting
+# with a non-zero code when a race is found.
+# The fix for the bug seems to be: https://go-review.googlesource.com/#/c/4371/
+# To work-around bugged go (<1.5) binaries, we enable "halt_on_error".
+GORACE=halt_on_error=1 go test $VT_GO_PARALLEL -race ./go/vt/... 2>&1 | tee $temp_log_file
+if [ ${PIPESTATUS[0]} -ne 0 ]; then
+  grep "WARNING: DATA RACE" -q $temp_log_file
+  if [ $? -eq 0 ]; then
+    echo
+    echo "ERROR: go test -race found a data race. See log above."
+    exit 2
+  fi
+fi
+
+echo
+echo "SUCCESS: No data race was found."