Function runTests

cmd/testwrapper/testwrapper.go:264–454

runTests runs the tests in pt and sends the results on ch. It sends a testAttempt for each test and a final testAttempt per pkg with pkgFinished set to true. Package build errors will not emit a testAttempt (as no valid JSON is produced) but the [os/exec.ExitError] will be returned. It calls close(c

(ctx context.Context, attempt int, pt *packageTests, goTestArgs, testArgs []string, ch chan<- *testAttempt)

// JSON is produced) but the [os/exec.ExitError] will be returned.
// It calls close(ch) when it's done.
func runTests(ctx context.Context, attempt int, pt *packageTests, goTestArgs, testArgs []string, ch chan<- *testAttempt) error {
	defer close(ch)
	args := []string{"test"}
	args = append(args, goTestArgs...)
	args = append(args, pt.Pattern)
	if len(pt.Tests) > 0 {
		// Specific tests requested (e.g. flaky test retry).
		runArg := strings.Join(pt.Tests, "|")
		args = append(args, "--run", runArg)
	} else if shardSpec := os.Getenv("TS_TEST_SHARD"); shardSpec != "" {
		// Automatic test-name sharding: list tests and filter by hash.
		shardTests, err := testsForShard(ctx, pt.Pattern, shardSpec)
		if err != nil {
			return err
		}
		if len(shardTests) == 0 {
			ch <- &testAttempt{pkg: pt.Pattern, outcome: outcomeSkip, pkgFinished: true}
			return nil
		}
		quoted := make([]string, len(shardTests))
		for i, name := range shardTests {
			quoted[i] = regexp.QuoteMeta(name)
		}
		args = append(args, "--run", "^("+strings.Join(quoted, "|")+")$")
	}
	args = append(args, testArgs...)
	args = append(args, "-json")
	if debug {
		fmt.Println("running", strings.Join(args, " "))
	}
	cmd := exec.CommandContext(ctx, "go", args...)
	r, err := cmd.StdoutPipe()
	if err != nil {
		log.Printf("error creating stdout pipe: %v", err)
	}
	defer r.Close()
	cmd.Stderr = os.Stderr

	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, attempt))

	if err := cmd.Start(); err != nil {
		log.Printf("error starting test: %v", err)
		os.Exit(1)
	}

	pkgCached := map[string]bool{}

	s := bufio.NewScanner(r)
	resultMap := make(map[string]map[string]*testAttempt) // pkg -> test -> testAttempt
	for s.Scan() {
		var goOutput goTestOutput
		if err := json.Unmarshal(s.Bytes(), &goOutput); err != nil {
			return fmt.Errorf("failed to parse go test output %q: %w", s.Bytes(), err)
		}
		pkg := cmp.Or(