whatcanGOwrong

go/pkg/mod/golang.org/x/vuln@v1.0.4/internal/testenv/testenv.go

@@ -0,0 +1,128 @@
+// Copyright 2015 The Go 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 testenv
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"sync"
+	"testing"
+)
+
+var origEnv = os.Environ()
+
+// NeedsExec checks that the current system can start new processes
+// using os.StartProcess or (more commonly) exec.Command.
+// If not, NeedsExec calls t.Skip with an explanation.
+//
+// On some platforms NeedsExec checks for exec support by re-executing the
+// current executable, which must be a binary built by 'go test'.
+// We intentionally do not provide a HasExec function because of the risk of
+// inappropriate recursion in TestMain functions.
+func NeedsExec(t testing.TB) {
+	tryExecOnce.Do(func() {
+		tryExecErr = tryExec()
+	})
+	if tryExecErr != nil {
+		t.Helper()
+		t.Skipf("skipping test: cannot exec subprocess on %s/%s: %v", runtime.GOOS, runtime.GOARCH, tryExecErr)
+	}
+}
+
+var (
+	tryExecOnce sync.Once
+	tryExecErr  error
+)
+
+func tryExec() error {
+	switch runtime.GOOS {
+	case "aix",
+		"android",
+		"darwin",
+		"dragonfly",
+		"freebsd",
+		"illumos",
+		"linux",
+		"netbsd",
+		"openbsd",
+		"plan9",
+		"solaris",
+		"windows":
+		// Known OS that isn't ios or wasm; assume that exec works.
+		return nil
+	default:
+	}
+
+	// ios has an exec syscall but on real iOS devices it might return a
+	// permission error. In an emulated environment (such as a Corellium host)
+	// it might succeed, so if we need to exec we'll just have to try it and
+	// find out.
+	//
+	// As of 2023-04-19 wasip1 and js don't have exec syscalls at all, but we
+	// may as well use the same path so that this branch can be tested without
+	// an ios environment.
+
+	if flag.Lookup("test.list") == nil {
+		// This isn't a standard 'go test' binary, so we don't know how to
+		// self-exec in a way that should succeed without side effects.
+		// Just forget it.
+		return errors.New("can't probe for exec support with a non-test executable")
+	}
+
+	// We know that this is a test executable. We should be able to run it with a
+	// no-op flag to check for overall exec support.
+	exe, err := os.Executable()
+	if err != nil {
+		return fmt.Errorf("can't probe for exec support: %w", err)
+	}
+	cmd := exec.Command(exe, "-test.list=^$")
+	cmd.Env = origEnv
+	return cmd.Run()
+}
+
+func NeedsGoBuild(t testing.TB) {
+	goBuildOnce.Do(func() {
+		dir, err := os.MkdirTemp("", "testenv-*")
+		if err != nil {
+			goBuildErr = err
+			return
+		}
+		defer os.RemoveAll(dir)
+
+		mainGo := filepath.Join(dir, "main.go")
+		if err := os.WriteFile(mainGo, []byte("package main\nfunc main() {}\n"), 0644); err != nil {
+			t.Fatal(err)
+		}
+		cmd := exec.Command("go", "build", "-o", os.DevNull, mainGo)
+		cmd.Dir = dir
+		if err := cmd.Run(); err != nil {
+			goBuildErr = fmt.Errorf("%v: %v", cmd, err)
+		}
+	})
+
+	if goBuildErr != nil {
+		t.Helper()
+		t.Skipf("skipping test: 'go build' not supported on %s/%s", runtime.GOOS, runtime.GOARCH)
+	}
+}
+
+var (
+	goBuildOnce sync.Once
+	goBuildErr  error
+)
+
+// NeedsLocalhostNet skips t if networking does not work for ports opened
+// with "localhost".
+func NeedsLocalhostNet(t testing.TB) {
+	switch runtime.GOOS {
+	case "js", "wasip1":
+		t.Skipf(`Listening on "localhost" fails on %s; see https://go.dev/issue/59718`, runtime.GOOS)
+	}
+}