whatcanGOwrong

go/pkg/mod/go.starlark.net@v0.0.0-20231101134539-556fd59b42f6/starlark/profile_test.go

@@ -0,0 +1,81 @@
+// Copyright 2019 The Bazel Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package starlark_test
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+
+	"go.starlark.net/starlark"
+)
+
+// TestProfile is a simple integration test that the profiler
+// emits minimally plausible pprof-compatible output.
+func TestProfile(t *testing.T) {
+	prof, err := os.CreateTemp(t.TempDir(), "profile_test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer prof.Close()
+	if err := starlark.StartProfile(prof); err != nil {
+		t.Fatal(err)
+	}
+
+	const src = `
+def fibonacci(n):
+	x, y = 1, 1
+	for i in range(n):
+		x, y = y, x+y
+	return y
+
+fibonacci(100000)
+`
+
+	thread := new(starlark.Thread)
+	if _, err := starlark.ExecFile(thread, "foo.star", src, nil); err != nil {
+		_ = starlark.StopProfile()
+		t.Fatal(err)
+	}
+	if err := starlark.StopProfile(); err != nil {
+		t.Fatal(err)
+	}
+	prof.Sync()
+	cmd := exec.Command("go", "tool", "pprof", "-top", prof.Name())
+	cmd.Stderr = new(bytes.Buffer)
+	cmd.Stdout = new(bytes.Buffer)
+	if err := cmd.Run(); err != nil {
+		t.Fatalf("pprof failed: %v; output=<<%s>>", err, cmd.Stderr)
+	}
+
+	// Typical output (may vary by go release):
+	//
+	// Type: wall
+	// Time: Apr 4, 2019 at 11:10am (EDT)
+	// Duration: 251.62ms, Total samples = 250ms (99.36%)
+	// Showing nodes accounting for 250ms, 100% of 250ms total
+	//  flat  flat%   sum%        cum   cum%
+	// 320ms   100%   100%      320ms   100%  fibonacci
+	//     0     0%   100%      320ms   100%  foo.star
+	//
+	// We'll assert a few key substrings are present.
+	got := fmt.Sprint(cmd.Stdout)
+	for _, want := range []string{
+		"flat%",
+		"fibonacci",
+		"foo.star",
+	} {
+		if !strings.Contains(got, want) {
+			t.Errorf("output did not contain %q", want)
+		}
+	}
+	if t.Failed() {
+		t.Logf("stderr=%v", cmd.Stderr)
+		t.Logf("stdout=%v", cmd.Stdout)
+	}
+}