testing, testing/synctest: write bubble errors to parent test log

Ensure that log messages written to the testing.T created by
synctest.Test appear in the test output when a test fails.

Fixes #73902

Change-Id: Ie97f5efe54eb003e6c0a5394c2def4cac1520ecb
Reviewed-on: https://go-review.googlesource.com/c/go/+/676995
Reviewed-by: Alan Donovan <adonovan@google.com>
Auto-Submit: Damien Neil <dneil@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

2 files changed, 32 insertions, 13 deletions

diff --git a/src/testing/synctest/synctest_test.go b/src/testing/synctest/synctest_test.go
index 4897df999e..822fd6fe1c 100644
--- a/src/testing/synctest/synctest_test.go
+++ b/src/testing/synctest/synctest_test.go
@@ -22,37 +22,56 @@ func TestSuccess(t *testing.T) {
 }
 
 func TestFatal(t *testing.T) {
-	runTest(t, func() {
+	runTest(t, nil, func() {
 		synctest.Test(t, func(t *testing.T) {
 			t.Fatal("fatal")
 		})
-	}, `^=== RUN   TestFatal
+	}, `^--- FAIL: TestFatal.*
     synctest_test.go:.* fatal
---- FAIL: TestFatal.*
 FAIL
 $`)
 }
 
 func TestError(t *testing.T) {
-	runTest(t, func() {
+	runTest(t, nil, func() {
 		synctest.Test(t, func(t *testing.T) {
 			t.Error("error")
 		})
-	}, `^=== RUN   TestError
+	}, `^--- FAIL: TestError.*
     synctest_test.go:.* error
---- FAIL: TestError.*
+FAIL
+$`)
+}
+
+func TestVerboseError(t *testing.T) {
+	runTest(t, []string{"-test.v"}, func() {
+		synctest.Test(t, func(t *testing.T) {
+			t.Error("error")
+		})
+	}, `^=== RUN   TestVerboseError
+    synctest_test.go:.* error
+--- FAIL: TestVerboseError.*
 FAIL
 $`)
 }
 
 func TestSkip(t *testing.T) {
-	runTest(t, func() {
+	runTest(t, nil, func() {
+		synctest.Test(t, func(t *testing.T) {
+			t.Skip("skip")
+		})
+	}, `^PASS
+$`)
+}
+
+func TestVerboseSkip(t *testing.T) {
+	runTest(t, []string{"-test.v"}, func() {
 		synctest.Test(t, func(t *testing.T) {
 			t.Skip("skip")
 		})
-	}, `^=== RUN   TestSkip
+	}, `^=== RUN   TestVerboseSkip
     synctest_test.go:.* skip
---- PASS: TestSkip.*
+--- PASS: TestVerboseSkip.*
 PASS
 $`)
 }
@@ -131,7 +150,7 @@ func wantPanic(t *testing.T, want string) {
 	}
 }
 
-func runTest(t *testing.T, f func(), pattern string) {
+func runTest(t *testing.T, args []string, f func(), pattern string) {
 	if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
 		f()
 		return
@@ -139,7 +158,8 @@ func runTest(t *testing.T, f func(), pattern string) {
 	t.Helper()
 	re := regexp.MustCompile(pattern)
 	testenv.MustHaveExec(t)
-	cmd := testenv.Command(t, testenv.Executable(t), "-test.run=^"+t.Name()+"$", "-test.v", "-test.count=1")
+	cmd := testenv.Command(t, testenv.Executable(t), "-test.run=^"+regexp.QuoteMeta(t.Name())+"$", "-test.count=1")
+	cmd.Args = append(cmd.Args, args...)
 	cmd = testenv.CleanCmdEnv(cmd)
 	cmd.Env = append(cmd.Env, "GO_WANT_HELPER_PROCESS=1")
 	out, _ := cmd.CombinedOutput()
diff --git a/src/testing/testing.go b/src/testing/testing.go
index 85ac1aeb32..43ef9eef09 100644
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -1045,7 +1045,7 @@ func (c *common) destination() *common {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
-	if !c.done {
+	if !c.done && !c.isSynctest {
 		return c
 	}
 	for parent := c.parent; parent != nil; parent = parent.parent {
@@ -2037,7 +2037,6 @@ func testingSynctestTest(t *T, f func(*T)) {
 		},
 		tstate: t.tstate,
 	}
-	t2.setOutputWriter()
 
 	go tRunner(t2, f)
 	if !<-t2.signal {