net/http: replace z_last_test hack with testing.Main

LGTM=adg
R=rsc, adg
CC=golang-codereviews
https://golang.org/cl/144240043

src/net/http/z_last_test.go → src/net/http/main_test.go

@@ -5,7 +5,9 @@
 package http_test
 
 import (
+	"fmt"
 	"net/http"
+	"os"
 	"runtime"
 	"sort"
 	"strings"
@@ -13,6 +15,14 @@ import (
 	"time"
 )
 
+func TestMain(m *testing.M) {
+	v := m.Run()
+	if v == 0 && goroutineLeaked() {
+		os.Exit(1)
+	}
+	os.Exit(v)
+}
+
 func interestingGoroutines() (gs []string) {
 	buf := make([]byte, 2<<20)
 	buf = buf[:runtime.Stack(buf, true)]
@@ -30,6 +40,7 @@ func interestingGoroutines() (gs []string) {
 			// These only show up with GOTRACEBACK=2; Issue 5005 (comment 28)
 			strings.Contains(stack, "runtime.goexit") ||
 			strings.Contains(stack, "created by runtime.gc") ||
+			strings.Contains(stack, "net/http_test.interestingGoroutines") ||
 			strings.Contains(stack, "runtime.MHeap_Scavenger") {
 			continue
 		}
@@ -40,10 +51,10 @@ func interestingGoroutines() (gs []string) {
 }
 
 // Verify the other tests didn't leave any goroutines running.
-// This is in a file named z_last_test.go so it sorts at the end.
-func TestGoroutinesRunning(t *testing.T) {
+func goroutineLeaked() bool {
 	if testing.Short() {
-		t.Skip("not counting goroutines for leakage in -short mode")
+		// not counting goroutines for leakage in -short mode
+		return false
 	}
 	gs := interestingGoroutines()
 
@@ -54,13 +65,14 @@ func TestGoroutinesRunning(t *testing.T) {
 		n++
 	}
 
-	t.Logf("num goroutines = %d", n)
-	if n > 0 {
-		t.Error("Too many goroutines.")
-		for stack, count := range stackCount {
-			t.Logf("%d instances of:\n%s", count, stack)
-		}
+	if n == 0 {
+		return false
+	}
+	fmt.Fprintf(os.Stderr, "Too many goroutines running after net/http test(s).\n")
+	for stack, count := range stackCount {
+		fmt.Fprintf(os.Stderr, "%d instances of:\n%s", count, stack)
 	}
+	return true
 }
 
 func afterTest(t *testing.T) {