diff --git a/go/analysis/internal/unitchecker/unitchecker_test.go b/go/analysis/internal/unitchecker/unitchecker_test.go
index 872275f1..a00ce4f2 100644
--- a/go/analysis/internal/unitchecker/unitchecker_test.go
+++ b/go/analysis/internal/unitchecker/unitchecker_test.go
@@ -2,8 +2,13 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build go1.12
+
 package unitchecker_test
 
+// This test depends on go1.12 features such as go vet's support for
+// GOVETTOOL, and the (*os/exec.ExitError).ExitCode method.
+
 import (
 	"flag"
 	"log"