diff --git a/cmd/prometheus/main_unix_test.go b/cmd/prometheus/main_unix_test.go
index 7e1ebb01b..393c6f952 100644
--- a/cmd/prometheus/main_unix_test.go
+++ b/cmd/prometheus/main_unix_test.go
@@ -37,7 +37,7 @@ func TestStartupInterrupt(t *testing.T) {
 		return
 	}
 
-	done := make(chan error)
+	done := make(chan error, 1)
 	go func() {
 		done <- prom.Wait()
 	}()