internal/testenv: remove RunWithTimout

For most tests, the test's deadline itself is more appropriate than an
arbitrary timeout layered atop of it (especially once golang#48157 is
implemented), and testenv.Command already adds cleaner timeout
behavior when a command would run too close to the test's deadline.

That makes RunWithTimeout something of an attractive nuisance. For
now, migrate the two existing uses of it to testenv.CommandContext,
with a shorter timeout implemented using context.WithTimeout.

As a followup, we may want to drop the extra timeouts from these
invocations entirely.

Updates golang#50436.
Updates golang#37405.

Change-Id: I16840fd36c0137b6da87ec54012b3e44661f0d08
Reviewed-on: https://go-review.googlesource.com/c/go/+/445597
Reviewed-by: Ian Lance Taylor <[email protected]>
Run-TryBot: Bryan Mills <[email protected]>
Auto-Submit: Bryan Mills <[email protected]>
Reviewed-by: Austin Clements <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: Bryan C. Mills

src/internal/testenv/testenv.go

@@ -11,7 +11,6 @@
 package testenv
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"flag"
@@ -505,62 +504,6 @@ func SkipIfOptimizationOff(t testing.TB) {
 	}
 }
 
-// RunWithTimeout runs cmd and returns its combined output. If the
-// subprocess exits with a non-zero status, it will log that status
-// and return a non-nil error, but this is not considered fatal.
-func RunWithTimeout(t testing.TB, cmd *exec.Cmd) ([]byte, error) {
-	args := cmd.Args
-	if args == nil {
-		args = []string{cmd.Path}
-	}
-
-	var b bytes.Buffer
-	cmd.Stdout = &b
-	cmd.Stderr = &b
-	if err := cmd.Start(); err != nil {
-		t.Fatalf("starting %s: %v", args, err)
-	}
-
-	// If the process doesn't complete within 1 minute,
-	// assume it is hanging and kill it to get a stack trace.
-	p := cmd.Process
-	done := make(chan bool)
-	go func() {
-		scale := 1
-		// This GOARCH/GOOS test is copied from cmd/dist/test.go.
-		// TODO(iant): Have cmd/dist update the environment variable.
-		if runtime.GOARCH == "arm" || runtime.GOOS == "windows" {
-			scale = 2
-		}
-		if s := os.Getenv("GO_TEST_TIMEOUT_SCALE"); s != "" {
-			if sc, err := strconv.Atoi(s); err == nil {
-				scale = sc
-			}
-		}
-
-		select {
-		case <-done:
-		case <-time.After(time.Duration(scale) * time.Minute):
-			p.Signal(Sigquit)
-			// If SIGQUIT doesn't do it after a little
-			// while, kill the process.
-			select {
-			case <-done:
-			case <-time.After(time.Duration(scale) * 30 * time.Second):
-				p.Signal(os.Kill)
-			}
-		}
-	}()
-
-	err := cmd.Wait()
-	if err != nil {
-		t.Logf("%s exit status: %v", args, err)
-	}
-	close(done)
-
-	return b.Bytes(), err
-}
-
 // WriteImportcfg writes an importcfg file used by the compiler or linker to
 // dstPath containing entries for the packages in std and cmd in addition
 // to the package to package file mappings in additionalPackageFiles.

src/runtime/crash_test.go

@@ -6,6 +6,7 @@ package runtime_test
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"flag"
 	"fmt"
@@ -18,6 +19,7 @@ import (
 	"strings"
 	"sync"
 	"testing"
+	"time"
 )
 
 var toRemove []string
@@ -58,18 +60,27 @@ func runTestProg(t *testing.T, binary, name string, env ...string) string {
 }
 
 func runBuiltTestProg(t *testing.T, exe, name string, env ...string) string {
+	t.Helper()
+
 	if *flagQuick {
 		t.Skip("-quick")
 	}
 
-	testenv.MustHaveGoBuild(t)
-
-	cmd := testenv.CleanCmdEnv(exec.Command(exe, name))
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+	cmd := testenv.CleanCmdEnv(testenv.CommandContext(t, ctx, exe, name))
 	cmd.Env = append(cmd.Env, env...)
 	if testing.Short() {
 		cmd.Env = append(cmd.Env, "RUNTIME_TEST_SHORT=1")
 	}
-	out, _ := testenv.RunWithTimeout(t, cmd)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		if _, ok := err.(*exec.ExitError); ok {
+			t.Logf("%v: %v", cmd, err)
+		} else {
+			t.Fatalf("%v failed to start: %v", cmd, err)
+		}
+	}
 	return string(out)
 }
 

src/runtime/runtime-gdb_test.go

@@ -6,6 +6,7 @@ package runtime_test
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"internal/testenv"
 	"os"
@@ -16,6 +17,7 @@ import (
 	"strconv"
 	"strings"
 	"testing"
+	"time"
 )
 
 // NOTE: In some configurations, GDB will segfault when sent a SIGWINCH signal.
@@ -428,7 +430,9 @@ func TestGdbBacktrace(t *testing.T) {
 		"-ex", "continue",
 		filepath.Join(dir, "a.exe"),
 	}
-	got, err := testenv.RunWithTimeout(t, exec.Command("gdb", args...))
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+	got, err := testenv.CommandContext(t, ctx, "gdb", args...).CombinedOutput()
 	t.Logf("gdb output:\n%s", got)
 	if err != nil {
 		if bytes.Contains(got, []byte("internal-error: wait returned unexpected status 0x0")) {