testing: don't start timing a Parallel test until it's actually starting

Fixes #5285.

R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/13045044

diff --git a/src/pkg/testing/testing.go b/src/pkg/testing/testing.go
index 4c81201a84b0410fa00a008cce79046b5d75c33a..5019e0762697b7656f438cae85eafdf679f4b8e2 100644 (file)
--- a/src/pkg/testing/testing.go
+++ b/src/pkg/testing/testing.go
@@ -357,6 +357,9 @@ func (c *common) Skipped() bool {
 func (t *T) Parallel() {
        t.signal <- (*T)(nil) // Release main testing loop
        <-t.startParallel     // Wait for serial tests to finish
+       // Assuming Parallel is the first thing a test does, which is reasonable,
+       // reinitialize the test's start time because it's actually starting now.
+       t.start = time.Now()
 }
 
 // An internal type but exported because it is cross-package; part of the implementation
@@ -367,8 +370,6 @@ type InternalTest struct {
 }
 
 func tRunner(t *T, test *InternalTest) {
-       t.start = time.Now()
-
        // When this goroutine is done, either because test.F(t)
        // returned normally or because a test failure triggered
        // a call to runtime.Goexit, record the duration and send
@@ -384,6 +385,7 @@ func tRunner(t *T, test *InternalTest) {
                t.signal <- t
        }()
 
+       t.start = time.Now()
        test.F(t)
 }