Function runOneTest

cmd/testwrapper/testwrapper.go:463–533

runOneTest runs a single test in a single package via `go test -run` with a per-attempt -timeout. It returns the test's outcome (outcomePass / outcomeFail / outcomeSkip), the wall-clock time spent on this attempt (used for the per-test retry budget), and any captured test logs. On panic, timeout, o

(ctx context.Context, pkg, testName string, perAttemptTimeout time.Duration, attemptNum int, goTestArgs, testArgs []string)

// On panic, timeout, or any other failure mode where the test does not emit a
// pass/fail/skip JSON event, outcome is reported as outcomeFail.
func runOneTest(ctx context.Context, pkg, testName string, perAttemptTimeout time.Duration, attemptNum int, goTestArgs, testArgs []string) (outcome testOutcome, wallDur time.Duration, logs bytes.Buffer, err error) {
	goTestArgs, perAttemptTimeout = extractTimeout(goTestArgs, perAttemptTimeout)
	testArgs, perAttemptTimeout = extractTimeout(testArgs, perAttemptTimeout)
	args := []string{"test", "-json"}
	args = append(args, goTestArgs...)
	args = append(args, "-timeout", perAttemptTimeout.String())
	args = append(args, pkg)
	args = append(args, "--run", "^("+regexp.QuoteMeta(testName)+")$")
	args = append(args, testArgs...)

	if debug {
		fmt.Println("running", strings.Join(args, " "))
	}
	cmd := exec.CommandContext(ctx, "go", args...)
	// Strip TS_TEST_SHARD so the child doesn't try to shard inside a
	// single-test retry — we are telling it exactly what to run.
	cmd.Env = slices.DeleteFunc(os.Environ(), func(s string) bool {
		return strings.HasPrefix(s, "TS_TEST_SHARD=")
	})
	cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%d", flakytest.FlakeAttemptEnv, attemptNum))
	r, perr := cmd.StdoutPipe()
	if perr != nil {
		return "", 0, logs, fmt.Errorf("stdout pipe: %w", perr)
	}
	defer r.Close()
	cmd.Stderr = os.Stderr

	wallStart := time.Now()
	if err := cmd.Start(); err != nil {
		return "", 0, logs, fmt.Errorf("starting go test: %w", err)
	}

	s := bufio.NewScanner(r)
	for s.Scan() {
		var ev goTestOutput
		if err := json.Unmarshal(s.Bytes(), &ev); err != nil {
			continue
		}
		if ev.Test == "" {
			continue // package-level events ignored for single-test runs
		}
		// Collapse subtests to parent.
		parent, _, _ := strings.Cut(ev.Test, "/")
		if parent != testName {
			continue
		}
		switch ev.Action {
		case "pass", "fail", "skip":
			if ev.Test == testName {
				outcome = testOutcome(ev.Action)
			}
		case "output":
			logs.WriteString(ev.Output)
		}
	}
	waitErr := cmd.Wait()
	wallDur = time.Since(wallStart)
	if scanErr := s.Err(); scanErr != nil && err == nil {