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// 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 provides information about what functionality
// is available in different testing environments run by the Go team.
//
// It is an internal package because these details are specific
// to the Go team's test setup (on build.golang.org) and not
// fundamental to tests in general.
package testenv
import (
"bytes"
"errors"
"flag"
"fmt"
"internal/cfg"
"internal/platform"
"os"
"os/exec"
"path/filepath"
"runtime"
"strconv"
"strings"
"sync"
"testing"
)
// Save the original environment during init for use in checks. A test
// binary may modify its environment before calling HasExec to change its
// behavior (such as mimicking a command-line tool), and that modified
// environment might cause environment checks to behave erratically.
var origEnv = os.Environ()
// Builder reports the name of the builder running this test
// (for example, "linux-amd64" or "windows-386-gce").
// If the test is not running on the build infrastructure,
// Builder returns the empty string.
func Builder() string {
return os.Getenv("GO_BUILDER_NAME")
}
// HasGoBuild reports whether the current system can build programs with “go build”
// and then run them with os.StartProcess or exec.Command.
func HasGoBuild() bool {
if os.Getenv("GO_GCFLAGS") != "" {
// It's too much work to require every caller of the go command
// to pass along "-gcflags="+os.Getenv("GO_GCFLAGS").
// For now, if $GO_GCFLAGS is set, report that we simply can't
// run go build.
return false
}
goBuildOnce.Do(func() {
// To run 'go build', we need to be able to exec a 'go' command.
// We somewhat arbitrarily choose to exec 'go tool -n compile' because that
// also confirms that cmd/go can find the compiler. (Before CL 472096,
// we sometimes ended up with cmd/go installed in the test environment
// without a cmd/compile it could use to actually build things.)
cmd := exec.Command("go", "tool", "-n", "compile")
cmd.Env = origEnv
out, err := cmd.Output()
if err != nil {
goBuildErr = fmt.Errorf("%v: %w", cmd, err)
return
}
out = bytes.TrimSpace(out)
if len(out) == 0 {
goBuildErr = fmt.Errorf("%v: no tool reported", cmd)
return
}
if _, err := exec.LookPath(string(out)); err != nil {
goBuildErr = err
return
}
if platform.MustLinkExternal(runtime.GOOS, runtime.GOARCH, false) {
// We can assume that we always have a complete Go toolchain available.
// However, this platform requires a C linker to build even pure Go
// programs, including tests. Do we have one in the test environment?
// (On Android, for example, the device running the test might not have a
// C toolchain installed.)
//
// If CC is set explicitly, assume that we do. Otherwise, use 'go env CC'
// to determine which toolchain it would use by default.
if os.Getenv("CC") == "" {
cmd := exec.Command("go", "env", "CC")
cmd.Env = origEnv
out, err := cmd.Output()
if err != nil {
goBuildErr = fmt.Errorf("%v: %w", cmd, err)
return
}
out = bytes.TrimSpace(out)
if len(out) == 0 {
goBuildErr = fmt.Errorf("%v: no CC reported", cmd)
return
}
_, goBuildErr = exec.LookPath(string(out))
}
}
})
return goBuildErr == nil
}
var (
goBuildOnce sync.Once
goBuildErr error
)
// MustHaveGoBuild checks that the current system can build programs with “go build”
// and then run them with os.StartProcess or exec.Command.
// If not, MustHaveGoBuild calls t.Skip with an explanation.
func MustHaveGoBuild(t testing.TB) {
if os.Getenv("GO_GCFLAGS") != "" {
t.Helper()
t.Skipf("skipping test: 'go build' not compatible with setting $GO_GCFLAGS")
}
if !HasGoBuild() {
t.Helper()
t.Skipf("skipping test: 'go build' unavailable: %v", goBuildErr)
}
}
// HasGoRun reports whether the current system can run programs with “go run”.
func HasGoRun() bool {
// For now, having go run and having go build are the same.
return HasGoBuild()
}
// MustHaveGoRun checks that the current system can run programs with “go run”.
// If not, MustHaveGoRun calls t.Skip with an explanation.
func MustHaveGoRun(t testing.TB) {
if !HasGoRun() {
t.Skipf("skipping test: 'go run' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
}
}
// HasParallelism reports whether the current system can execute multiple
// threads in parallel.
// There is a copy of this function in cmd/dist/test.go.
func HasParallelism() bool {
switch runtime.GOOS {
case "js", "wasip1":
return false
}
return true
}
// MustHaveParallelism checks that the current system can execute multiple
// threads in parallel. If not, MustHaveParallelism calls t.Skip with an explanation.
func MustHaveParallelism(t testing.TB) {
if !HasParallelism() {
t.Skipf("skipping test: no parallelism available on %s/%s", runtime.GOOS, runtime.GOARCH)
}
}
// GoToolPath reports the path to the Go tool.
// It is a convenience wrapper around GoTool.
// If the tool is unavailable GoToolPath calls t.Skip.
// If the tool should be available and isn't, GoToolPath calls t.Fatal.
func GoToolPath(t testing.TB) string {
MustHaveGoBuild(t)
path, err := GoTool()
if err != nil {
t.Fatal(err)
}
// Add all environment variables that affect the Go command to test metadata.
// Cached test results will be invalidate when these variables change.
// See golang.org/issue/32285.
for _, envVar := range strings.Fields(cfg.KnownEnv) {
os.Getenv(envVar)
}
return path
}
var (
gorootOnce sync.Once
gorootPath string
gorootErr error
)
func findGOROOT() (string, error) {
gorootOnce.Do(func() {
gorootPath = runtime.GOROOT()
if gorootPath != "" {
// If runtime.GOROOT() is non-empty, assume that it is valid.
//
// (It might not be: for example, the user may have explicitly set GOROOT
// to the wrong directory. But this case is
// rare, and if that happens the user can fix what they broke.)
return
}
// runtime.GOROOT doesn't know where GOROOT is (perhaps because the test
// binary was built with -trimpath).
//
// Since this is internal/testenv, we can cheat and assume that the caller
// is a test of some package in a subdirectory of GOROOT/src. ('go test'
// runs the test in the directory containing the packaged under test.) That
// means that if we start walking up the tree, we should eventually find
// GOROOT/src/go.mod, and we can report the parent directory of that.
//
// Notably, this works even if we can't run 'go env GOROOT' as a
// subprocess.
cwd, err := os.Getwd()
if err != nil {
gorootErr = fmt.Errorf("finding GOROOT: %w", err)
return
}
dir := cwd
for {
parent := filepath.Dir(dir)
if parent == dir {
// dir is either "." or only a volume name.
gorootErr = fmt.Errorf("failed to locate GOROOT/src in any parent directory")
return
}
if base := filepath.Base(dir); base != "src" {
dir = parent
continue // dir cannot be GOROOT/src if it doesn't end in "src".
}
b, err := os.ReadFile(filepath.Join(dir, "go.mod"))
if err != nil {
if os.IsNotExist(err) {
dir = parent
continue
}
gorootErr = fmt.Errorf("finding GOROOT: %w", err)
return
}
goMod := string(b)
for goMod != "" {
var line string
line, goMod, _ = strings.Cut(goMod, "\n")
fields := strings.Fields(line)
if len(fields) >= 2 && fields[0] == "module" && fields[1] == "std" {
// Found "module std", which is the module declaration in GOROOT/src!
gorootPath = parent
return
}
}
}
})
return gorootPath, gorootErr
}
// GOROOT reports the path to the directory containing the root of the Go
// project source tree. This is normally equivalent to runtime.GOROOT, but
// works even if the test binary was built with -trimpath and cannot exec
// 'go env GOROOT'.
//
// If GOROOT cannot be found, GOROOT skips t if t is non-nil,
// or panics otherwise.
func GOROOT(t testing.TB) string {
path, err := findGOROOT()
if err != nil {
if t == nil {
panic(err)
}
t.Helper()
t.Skip(err)
}
return path
}
// GoTool reports the path to the Go tool.
func GoTool() (string, error) {
if !HasGoBuild() {
return "", errors.New("platform cannot run go tool")
}
goToolOnce.Do(func() {
goToolPath, goToolErr = exec.LookPath("go")
})
return goToolPath, goToolErr
}
var (
goToolOnce sync.Once
goToolPath string
goToolErr error
)
// HasSrc reports whether the entire source tree is available under GOROOT.
func HasSrc() bool {
switch runtime.GOOS {
case "ios":
return false
}
return true
}
// HasExternalNetwork reports whether the current system can use
// external (non-localhost) networks.
func HasExternalNetwork() bool {
return !testing.Short() && runtime.GOOS != "js" && runtime.GOOS != "wasip1"
}
// MustHaveExternalNetwork checks that the current system can use
// external (non-localhost) networks.
// If not, MustHaveExternalNetwork calls t.Skip with an explanation.
func MustHaveExternalNetwork(t testing.TB) {
if runtime.GOOS == "js" || runtime.GOOS == "wasip1" {
t.Helper()
t.Skipf("skipping test: no external network on %s", runtime.GOOS)
}
if testing.Short() {
t.Helper()
t.Skipf("skipping test: no external network in -short mode")
}
}
// HasCGO reports whether the current system can use cgo.
func HasCGO() bool {
hasCgoOnce.Do(func() {
goTool, err := GoTool()
if err != nil {
return
}
cmd := exec.Command(goTool, "env", "CGO_ENABLED")
cmd.Env = origEnv
out, err := cmd.Output()
if err != nil {
panic(fmt.Sprintf("%v: %v", cmd, out))
}
hasCgo, err = strconv.ParseBool(string(bytes.TrimSpace(out)))
if err != nil {
panic(fmt.Sprintf("%v: non-boolean output %q", cmd, out))
}
})
return hasCgo
}
var (
hasCgoOnce sync.Once
hasCgo bool
)
// MustHaveCGO calls t.Skip if cgo is not available.
func MustHaveCGO(t testing.TB) {
if !HasCGO() {
t.Skipf("skipping test: no cgo")
}
}
// CanInternalLink reports whether the current system can link programs with
// internal linking.
func CanInternalLink(withCgo bool) bool {
return !platform.MustLinkExternal(runtime.GOOS, runtime.GOARCH, withCgo)
}
// MustInternalLink checks that the current system can link programs with internal
// linking.
// If not, MustInternalLink calls t.Skip with an explanation.
func MustInternalLink(t testing.TB, withCgo bool) {
if !CanInternalLink(withCgo) {
if withCgo && CanInternalLink(false) {
t.Skipf("skipping test: internal linking on %s/%s is not supported with cgo", runtime.GOOS, runtime.GOARCH)
}
t.Skipf("skipping test: internal linking on %s/%s is not supported", runtime.GOOS, runtime.GOARCH)
}
}
// MustInternalLinkPIE checks whether the current system can link PIE binary using
// internal linking.
// If not, MustInternalLinkPIE calls t.Skip with an explanation.
func MustInternalLinkPIE(t testing.TB) {
if !platform.InternalLinkPIESupported(runtime.GOOS, runtime.GOARCH) {
t.Skipf("skipping test: internal linking for buildmode=pie on %s/%s is not supported", runtime.GOOS, runtime.GOARCH)
}
}
// MustHaveBuildMode reports whether the current system can build programs in
// the given build mode.
// If not, MustHaveBuildMode calls t.Skip with an explanation.
func MustHaveBuildMode(t testing.TB, buildmode string) {
if !platform.BuildModeSupported(runtime.Compiler, buildmode, runtime.GOOS, runtime.GOARCH) {
t.Skipf("skipping test: build mode %s on %s/%s is not supported by the %s compiler", buildmode, runtime.GOOS, runtime.GOARCH, runtime.Compiler)
}
}
// HasSymlink reports whether the current system can use os.Symlink.
func HasSymlink() bool {
ok, _ := hasSymlink()
return ok
}
// MustHaveSymlink reports whether the current system can use os.Symlink.
// If not, MustHaveSymlink calls t.Skip with an explanation.
func MustHaveSymlink(t testing.TB) {
ok, reason := hasSymlink()
if !ok {
t.Skipf("skipping test: cannot make symlinks on %s/%s: %s", runtime.GOOS, runtime.GOARCH, reason)
}
}
// HasLink reports whether the current system can use os.Link.
func HasLink() bool {
// From Android release M (Marshmallow), hard linking files is blocked
// and an attempt to call link() on a file will return EACCES.
// - https://code.google.com/p/android-developer-preview/issues/detail?id=3150
return runtime.GOOS != "plan9" && runtime.GOOS != "android"
}
// MustHaveLink reports whether the current system can use os.Link.
// If not, MustHaveLink calls t.Skip with an explanation.
func MustHaveLink(t testing.TB) {
if !HasLink() {
t.Skipf("skipping test: hardlinks are not supported on %s/%s", runtime.GOOS, runtime.GOARCH)
}
}
var flaky = flag.Bool("flaky", false, "run known-flaky tests too")
func SkipFlaky(t testing.TB, issue int) {
t.Helper()
if !*flaky {
t.Skipf("skipping known flaky test without the -flaky flag; see golang.org/issue/%d", issue)
}
}
func SkipFlakyNet(t testing.TB) {
t.Helper()
if v, _ := strconv.ParseBool(os.Getenv("GO_BUILDER_FLAKY_NET")); v {
t.Skip("skipping test on builder known to have frequent network failures")
}
}
// CPUIsSlow reports whether the CPU running the test is suspected to be slow.
func CPUIsSlow() bool {
switch runtime.GOARCH {
case "arm", "mips", "mipsle", "mips64", "mips64le", "wasm":
return true
}
return false
}
// SkipIfShortAndSlow skips t if -short is set and the CPU running the test is
// suspected to be slow.
//
// (This is useful for CPU-intensive tests that otherwise complete quickly.)
func SkipIfShortAndSlow(t testing.TB) {
if testing.Short() && CPUIsSlow() {
t.Helper()
t.Skipf("skipping test in -short mode on %s", runtime.GOARCH)
}
}
// SkipIfOptimizationOff skips t if optimization is disabled.
func SkipIfOptimizationOff(t testing.TB) {
if OptimizationOff() {
t.Helper()
t.Skip("skipping test with optimization disabled")
}
}
// WriteImportcfg writes an importcfg file used by the compiler or linker to
// dstPath containing entries for the file mappings in packageFiles, as well
// as for the packages transitively imported by the package(s) in pkgs.
//
// pkgs may include any package pattern that is valid to pass to 'go list',
// so it may also be a list of Go source files all in the same directory.
func WriteImportcfg(t testing.TB, dstPath string, packageFiles map[string]string, pkgs ...string) {
t.Helper()
icfg := new(bytes.Buffer)
icfg.WriteString("# import config\n")
for k, v := range packageFiles {
fmt.Fprintf(icfg, "packagefile %s=%s\n", k, v)
}
if len(pkgs) > 0 {
// Use 'go list' to resolve any missing packages and rewrite the import map.
cmd := Command(t, GoToolPath(t), "list", "-export", "-deps", "-f", `{{if ne .ImportPath "command-line-arguments"}}{{if .Export}}{{.ImportPath}}={{.Export}}{{end}}{{end}}`)
cmd.Args = append(cmd.Args, pkgs...)
cmd.Stderr = new(strings.Builder)
out, err := cmd.Output()
if err != nil {
t.Fatalf("%v: %v\n%s", cmd, err, cmd.Stderr)
}
for _, line := range strings.Split(string(out), "\n") {
if line == "" {
continue
}
importPath, export, ok := strings.Cut(line, "=")
if !ok {
t.Fatalf("invalid line in output from %v:\n%s", cmd, line)
}
if packageFiles[importPath] == "" {
fmt.Fprintf(icfg, "packagefile %s=%s\n", importPath, export)
}
}
}
if err := os.WriteFile(dstPath, icfg.Bytes(), 0666); err != nil {
t.Fatal(err)
}
}
// SyscallIsNotSupported reports whether err may indicate that a system call is
// not supported by the current platform or execution environment.
func SyscallIsNotSupported(err error) bool {
return syscallIsNotSupported(err)
}