cmd/go/internal/test: pass default timeout to test programs if it is …

…not given from command line

Make 'go test' command to pass the default timeout (10m) to test programs if the value is not given from command line.

Fixes golang#28147

src/cmd/go/go_test.go

@@ -6272,3 +6272,11 @@ func TestCoverpkgTestOnly(t *testing.T) {
 	tg.grepStderrNot("no packages being tested depend on matches", "bad match message")
 	tg.grepStdout("coverage: 100", "no coverage")
 }
+
+// Issue 28147.
+func TestGoTestWithoutTimeout(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.run("test", "-v", "testdata/src/testtimeout/testtimeout_test.go")
+	tg.grepStdout("10m0s", "default timeout was not set")
+}

src/cmd/go/internal/test/test.go

@@ -1122,7 +1122,15 @@ func (c *runCache) builderRunTest(b *work.Builder, a *work.Action) error {
 		}
 	}
 
-	cmd := exec.Command(args[0], args[1:]...)
+	var cmd *exec.Cmd
+
+	// If a test timeout was not given, pass the default timeout (10s) to test programs.
+	if len(testTimeout) == 0 {
+		cmd = exec.Command(args[0], append(args[1:], "-test.timeout=10m")...)
+	} else {
+		cmd = exec.Command(args[0], args[1:]...)
+	}
+
 	cmd.Dir = a.Package.Dir
 	cmd.Env = base.EnvForDir(cmd.Dir, cfg.OrigEnv)
 	cmd.Stdout = stdout

src/cmd/go/testdata/src/testtimeout/testtimeout_test.go

@@ -0,0 +1,11 @@
+package testtimeout
+
+import (
+	"flag"
+	"fmt"
+	"testing"
+)
+
+func TestTimeout(t *testing.T) {
+	fmt.Println(flag.Lookup("test.timeout").Value)
+}