testing: stream log output in verbose mode

Fixes #24929

Change-Id: Icc426068cd73b75b78001f55e1e5d81ccebbe854
Reviewed-on: https://go-review.googlesource.com/c/go/+/127120
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

1 files changed, 10 insertions, 3 deletions

diff --git a/src/testing/testing.go b/src/testing/testing.go
index 6ab9b79196..bbb10263c3 100644
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -479,6 +479,9 @@ func (c *common) decorate(s string, skip int) string {
 	buf := new(strings.Builder)
 	// Every line is indented at least 4 spaces.
 	buf.WriteString("    ")
+	if c.chatty {
+		fmt.Fprintf(buf, "%s: ", c.name)
+	}
 	fmt.Fprintf(buf, "%s:%d: ", file, line)
 	lines := strings.Split(s, "\n")
 	if l := len(lines); l > 1 && lines[l-1] == "" {
@@ -662,9 +665,7 @@ func (c *common) log(s string) {
 func (c *common) logDepth(s string, depth int) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	if !c.done {
-		c.output = append(c.output, c.decorate(s, depth+1)...)
-	} else {
+	if c.done {
 		// This test has already finished. Try and log this message
 		// with our parent. If we don't have a parent, panic.
 		for parent := c.parent; parent != nil; parent = parent.parent {
@@ -676,6 +677,12 @@ func (c *common) logDepth(s string, depth int) {
 			}
 		}
 		panic("Log in goroutine after " + c.name + " has completed")
+	} else {
+		if c.chatty {
+			fmt.Print(c.decorate(s, depth+1))
+			return
+		}
+		c.output = append(c.output, c.decorate(s, depth+1)...)
 	}
 }