testing: use debug.SetTraceback("all") to show all goroutines at test timeout

Fixes #13681.

Change-Id: I308930f4d9200fbe0f09cd08c38392ca1bb0db67
Reviewed-on: https://go-review.googlesource.com/18044
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

src/go/build/deps_test.go

@@ -165,7 +165,7 @@ var pkgDeps = map[string][]string{
 	"runtime/trace":  {"L0"},
 	"text/tabwriter": {"L2"},
 
-	"testing":          {"L2", "flag", "fmt", "os", "runtime/pprof", "runtime/trace", "time"},
+	"testing":          {"L2", "flag", "fmt", "os", "runtime/debug", "runtime/pprof", "runtime/trace", "time"},
 	"testing/iotest":   {"L2", "log"},
 	"testing/quick":    {"L2", "flag", "fmt", "reflect"},
 	"internal/testenv": {"L2", "os", "testing"},

src/runtime/debug/garbage_test.go

@@ -2,10 +2,11 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package debug
+package debug_test
 
 import (
 	"runtime"
+	. "runtime/debug"
 	"testing"
 	"time"
 )

src/runtime/debug/heapdump_test.go

@@ -2,12 +2,13 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package debug
+package debug_test
 
 import (
 	"io/ioutil"
 	"os"
 	"runtime"
+	. "runtime/debug"
 	"testing"
 )
 

src/runtime/debug/stack_test.go

@@ -2,9 +2,10 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package debug
+package debug_test
 
 import (
+	. "runtime/debug"
 	"strings"
 	"testing"
 )
@@ -51,9 +52,9 @@ func TestStack(t *testing.T) {
 	}
 	n++
 	frame("src/runtime/debug/stack.go", "runtime/debug.Stack")
-	frame("src/runtime/debug/stack_test.go", "runtime/debug.(*T).ptrmethod")
-	frame("src/runtime/debug/stack_test.go", "runtime/debug.T.method")
-	frame("src/runtime/debug/stack_test.go", "runtime/debug.TestStack")
+	frame("src/runtime/debug/stack_test.go", "runtime/debug_test.(*T).ptrmethod")
+	frame("src/runtime/debug/stack_test.go", "runtime/debug_test.T.method")
+	frame("src/runtime/debug/stack_test.go", "runtime/debug_test.TestStack")
 	frame("src/testing/testing.go", "")
 }
 

src/testing/testing.go

@@ -149,6 +149,7 @@ import (
 	"fmt"
 	"os"
 	"runtime"
+	"runtime/debug"
 	"runtime/pprof"
 	"runtime/trace"
 	"strconv"
@@ -714,6 +715,7 @@ var timer *time.Timer
 func startAlarm() {
 	if *timeout > 0 {
 		timer = time.AfterFunc(*timeout, func() {
+			debug.SetTraceback("all")
 			panic(fmt.Sprintf("test timed out after %v", *timeout))
 		})
 	}