t.Skip("asynchronous preemption not supported on this platform")
	}
	output := runTestProg(t, "testprog", "AsyncPreempt")
	want := "OK\n"
	if output != want {
		t.Fatalf("want %s, got %s\n", want, output)
	}
}

func TestGCFairness(t *testing.T) {
	output := runTestProg(t, "testprog", "GCFairness")
	want := "OK\n"
	if output != want {
		t.Fatalf("want %s, got %s\n", want, output)
	}
}

	"fmt"
	"internal/trace/raw"
	"internal/trace/version"
	"io"
	"log"
	"os"
	"os/exec"
)

func main() {
	// Create command.
	var trace, stderr bytes.Buffer
	cmd := exec.Command("go", "run", "./testprog/main.go")
	cmd.Stdout = &trace
	cmd.Stderr = &stderr

	// Run trace program; the trace will appear in stdout.
	fmt.Fprintln(os.Stderr, "running trace program...")
	if err := cmd.Run(); err != nil {

)

func TestGcSys(t *testing.T) {
	t.Skip("skipping known-flaky test; golang.org/issue/37331")
	if os.Getenv("GOGC") == "off" {
		t.Skip("skipping test; GOGC=off in environment")
	}
	got := runTestProg(t, "testprog", "GCSys")
	want := "OK\n"
	if got != want {
		t.Fatalf("expected %q, but got %q", want, got)
	}
}

func TestGcDeepNesting(t *testing.T) {
	type T [2][2][2][2][2][2][2][2][2][2]*int
	a := new(T)

		// affect this test and this is itself a test of a debug mode, it's not
		// a high priority.
		testenv.SkipFlaky(t, 55160)
	}

	exe, err := buildTestProg(t, "testprog")
	if err != nil {
		t.Fatal(err)
	}

	cmd := testenv.Command(t, exe, "CrashDumpsAllThreads")
	cmd = testenv.CleanCmdEnv(cmd)
	cmd.Dir = t.TempDir() // put any core file in tempdir
	cmd.Env = append(cmd.Env,

func TestDebugLogBuild(t *testing.T) {
	testenv.MustHaveGoBuild(t)

	// It doesn't matter which program we build, anything will rebuild the
	// runtime.
	if _, err := buildTestProg(t, "testprog", "-tags=debuglog"); err != nil {
		t.Fatal(err)
	}

	}
}

func TestTracebackAncestors(t *testing.T) {
	goroutineRegex := regexp.MustCompile(`goroutine [0-9]+ \[`)
	for _, tracebackDepth := range []int{0, 1, 5, 50} {
		output := runTestProg(t, "testprog", "TracebackAncestors", fmt.Sprintf("GODEBUG=tracebackancestors=%d", tracebackDepth))

		numGoroutines := 3
		numFrames := 2
		ancestorsExpected := numGoroutines
		if numGoroutines > tracebackDepth {

	testenv.MustHaveGoRun(t)

	tmpdir := t.TempDir()

	src := filepath.Join(tmpdir, "a.go")
	file, err := os.Create(src)
	if err != nil {
		t.Fatal(err)
	}
	err = template.Must(template.New("main").Parse(testprog)).Execute(file, linktype != linkNoCgo)
	if err != nil {
		if err := file.Close(); err != nil {
			t.Error(err)
		}
		t.Fatal(err)
	}
	if err := file.Close(); err != nil {
		t.Fatal(err)
	}

	if !platform.ExecutableHasDWARF(runtime.GOOS, runtime.GOARCH) {
		t.Skipf("skipping on %s/%s: no DWARF symbol table in executables", runtime.GOOS, runtime.GOARCH)
	}

	t.Parallel()

	for _, prog := range []string{"testprog", "testprogcgo"} {
		prog := prog
		expectDWARF := expectDWARF
		if runtime.GOOS == "aix" && prog == "testprogcgo" {
			extld := os.Getenv("CC")
			if extld == "" {
				extld = "gcc"
			}

		type frame struct {
			fn   string
			line int
		}
		type evDesc struct {
			kind   trace.EventKind
			match  string
			frames []frame
		}
		// mainLine is the line number of `func main()` in testprog/stacks.go.
		const mainLine = 21
		want := []evDesc{
			{trace.EventStateTransition, "Goroutine Running->Runnable", []frame{
				{"main.main", mainLine + 82},
			}},

		testenv.SkipFlaky(t, 49681)
	}
	o := runTestProg(t, "testprog", "RaiseException")
	if strings.Contains(o, "RaiseException should not return") {
		t.Fatalf("RaiseException did not crash program: %v", o)
	}
	if !strings.Contains(o, "Exception 0xbad") {
		t.Fatalf("No stack trace: %v", o)
	}
}

func TestZeroDivisionException(t *testing.T) {
	o := runTestProg(t, "testprog", "ZeroDivisionException")