Adding upstream version 1.18.10.upstream/1.18.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2890 insertions, 0 deletions

diff --git a/src/cmd/go/go_test.go b/src/cmd/go/go_test.go
new file mode 100644
index 0000000..1ea347c
--- /dev/null
+++ b/src/cmd/go/go_test.go
@@ -0,0 +1,2890 @@
+// 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 main_test
+
+import (
+	"bytes"
+	"debug/elf"
+	"debug/macho"
+	"debug/pe"
+	"encoding/binary"
+	"flag"
+	"fmt"
+	"go/format"
+	"internal/godebug"
+	"internal/race"
+	"internal/testenv"
+	"io"
+	"io/fs"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"cmd/go/internal/cache"
+	"cmd/go/internal/cfg"
+	"cmd/go/internal/robustio"
+	"cmd/internal/sys"
+)
+
+func init() {
+	// GOVCS defaults to public:git|hg,private:all,
+	// which breaks many tests here - they can't use non-git, non-hg VCS at all!
+	// Change to fully permissive.
+	// The tests of the GOVCS setting itself are in ../../testdata/script/govcs.txt.
+	os.Setenv("GOVCS", "*:all")
+}
+
+var (
+	canRace          = false // whether we can run the race detector
+	canCgo           = false // whether we can use cgo
+	canMSan          = false // whether we can run the memory sanitizer
+	canASan          = false // whether we can run the address sanitizer
+	canFuzz          = false // whether we can search for new fuzz failures
+	fuzzInstrumented = false // whether fuzzing uses instrumentation
+)
+
+var exeSuffix string = func() string {
+	if runtime.GOOS == "windows" {
+		return ".exe"
+	}
+	return ""
+}()
+
+func tooSlow(t *testing.T) {
+	if testing.Short() {
+		// In -short mode; skip test, except run it on the {darwin,linux,windows}/amd64 builders.
+		if testenv.Builder() != "" && runtime.GOARCH == "amd64" && (runtime.GOOS == "linux" || runtime.GOOS == "darwin" || runtime.GOOS == "windows") {
+			return
+		}
+		t.Helper()
+		t.Skip("skipping test in -short mode")
+	}
+}
+
+// testGOROOT is the GOROOT to use when running testgo, a cmd/go binary
+// build from this process's current GOROOT, but run from a different
+// (temp) directory.
+var testGOROOT string
+
+var testGOCACHE string
+
+var testGo string
+var testTmpDir string
+var testBin string
+
+// The TestMain function creates a go command for testing purposes and
+// deletes it after the tests have been run.
+func TestMain(m *testing.M) {
+	// $GO_GCFLAGS a compiler debug flag known to cmd/dist, make.bash, etc.
+	// It is not a standard go command flag; use os.Getenv, not cfg.Getenv.
+	if os.Getenv("GO_GCFLAGS") != "" {
+		fmt.Fprintf(os.Stderr, "testing: warning: no tests to run\n") // magic string for cmd/go
+		fmt.Printf("cmd/go test is not compatible with $GO_GCFLAGS being set\n")
+		fmt.Printf("SKIP\n")
+		return
+	}
+
+	flag.Parse()
+
+	if *proxyAddr != "" {
+		StartProxy()
+		select {}
+	}
+
+	// Run with a temporary TMPDIR to check that the tests don't
+	// leave anything behind.
+	topTmpdir, err := os.MkdirTemp("", "cmd-go-test-")
+	if err != nil {
+		log.Fatal(err)
+	}
+	if !*testWork {
+		defer removeAll(topTmpdir)
+	}
+	os.Setenv(tempEnvName(), topTmpdir)
+
+	dir, err := os.MkdirTemp(topTmpdir, "tmpdir")
+	if err != nil {
+		log.Fatal(err)
+	}
+	testTmpDir = dir
+	if !*testWork {
+		defer removeAll(testTmpDir)
+	}
+
+	testGOCACHE = cache.DefaultDir()
+	if testenv.HasGoBuild() {
+		testBin = filepath.Join(testTmpDir, "testbin")
+		if err := os.Mkdir(testBin, 0777); err != nil {
+			log.Fatal(err)
+		}
+		testGo = filepath.Join(testBin, "go"+exeSuffix)
+		args := []string{"build", "-tags", "testgo", "-o", testGo}
+		if race.Enabled {
+			args = append(args, "-race")
+		}
+		gotool, err := testenv.GoTool()
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "locating go tool: ", err)
+			os.Exit(2)
+		}
+
+		goEnv := func(name string) string {
+			out, err := exec.Command(gotool, "env", name).CombinedOutput()
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "go env %s: %v\n%s", name, err, out)
+				os.Exit(2)
+			}
+			return strings.TrimSpace(string(out))
+		}
+		testGOROOT = goEnv("GOROOT")
+		os.Setenv("TESTGO_GOROOT", testGOROOT)
+		// Ensure that GOROOT is set explicitly.
+		// Otherwise, if the toolchain was built with GOROOT_FINAL set but has not
+		// yet been moved to its final location, programs that invoke runtime.GOROOT
+		// may accidentally use the wrong path.
+		os.Setenv("GOROOT", testGOROOT)
+
+		// The whole GOROOT/pkg tree was installed using the GOHOSTOS/GOHOSTARCH
+		// toolchain (installed in GOROOT/pkg/tool/GOHOSTOS_GOHOSTARCH).
+		// The testgo.exe we are about to create will be built for GOOS/GOARCH,
+		// which means it will use the GOOS/GOARCH toolchain
+		// (installed in GOROOT/pkg/tool/GOOS_GOARCH).
+		// If these are not the same toolchain, then the entire standard library
+		// will look out of date (the compilers in those two different tool directories
+		// are built for different architectures and have different build IDs),
+		// which will cause many tests to do unnecessary rebuilds and some
+		// tests to attempt to overwrite the installed standard library.
+		// Bail out entirely in this case.
+		hostGOOS := goEnv("GOHOSTOS")
+		hostGOARCH := goEnv("GOHOSTARCH")
+		if hostGOOS != runtime.GOOS || hostGOARCH != runtime.GOARCH {
+			fmt.Fprintf(os.Stderr, "testing: warning: no tests to run\n") // magic string for cmd/go
+			fmt.Printf("cmd/go test is not compatible with GOOS/GOARCH != GOHOSTOS/GOHOSTARCH (%s/%s != %s/%s)\n", runtime.GOOS, runtime.GOARCH, hostGOOS, hostGOARCH)
+			fmt.Printf("SKIP\n")
+			return
+		}
+
+		buildCmd := exec.Command(gotool, args...)
+		buildCmd.Env = append(os.Environ(), "GOFLAGS=-mod=vendor")
+		out, err := buildCmd.CombinedOutput()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "building testgo failed: %v\n%s", err, out)
+			os.Exit(2)
+		}
+
+		cmd := exec.Command(testGo, "env", "CGO_ENABLED")
+		cmd.Stderr = new(strings.Builder)
+		if out, err := cmd.Output(); err != nil {
+			fmt.Fprintf(os.Stderr, "running testgo failed: %v\n%s", err, cmd.Stderr)
+			os.Exit(2)
+		} else {
+			canCgo, err = strconv.ParseBool(strings.TrimSpace(string(out)))
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "can't parse go env CGO_ENABLED output: %v\n", strings.TrimSpace(string(out)))
+			}
+		}
+
+		out, err = exec.Command(gotool, "env", "GOCACHE").CombinedOutput()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "could not find testing GOCACHE: %v\n%s", err, out)
+			os.Exit(2)
+		}
+		testGOCACHE = strings.TrimSpace(string(out))
+
+		canMSan = canCgo && sys.MSanSupported(runtime.GOOS, runtime.GOARCH)
+		canASan = canCgo && sys.ASanSupported(runtime.GOOS, runtime.GOARCH)
+		canRace = canCgo && sys.RaceDetectorSupported(runtime.GOOS, runtime.GOARCH)
+		// The race detector doesn't work on Alpine Linux:
+		// golang.org/issue/14481
+		// gccgo does not support the race detector.
+		if isAlpineLinux() || runtime.Compiler == "gccgo" {
+			canRace = false
+		}
+		canFuzz = sys.FuzzSupported(runtime.GOOS, runtime.GOARCH)
+		fuzzInstrumented = sys.FuzzInstrumented(runtime.GOOS, runtime.GOARCH)
+	}
+	// Don't let these environment variables confuse the test.
+	os.Setenv("GOENV", "off")
+	os.Unsetenv("GOFLAGS")
+	os.Unsetenv("GOBIN")
+	os.Unsetenv("GOPATH")
+	os.Unsetenv("GIT_ALLOW_PROTOCOL")
+	os.Setenv("HOME", "/test-go-home-does-not-exist")
+	// On some systems the default C compiler is ccache.
+	// Setting HOME to a non-existent directory will break
+	// those systems. Disable ccache and use real compiler. Issue 17668.
+	os.Setenv("CCACHE_DISABLE", "1")
+	if cfg.Getenv("GOCACHE") == "" {
+		os.Setenv("GOCACHE", testGOCACHE) // because $HOME is gone
+	}
+
+	r := m.Run()
+	if !*testWork {
+		removeAll(testTmpDir) // os.Exit won't run defer
+	}
+
+	if !*testWork {
+		// There shouldn't be anything left in topTmpdir.
+		dirf, err := os.Open(topTmpdir)
+		if err != nil {
+			log.Fatal(err)
+		}
+		names, err := dirf.Readdirnames(0)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if len(names) > 0 {
+			log.Fatalf("unexpected files left in tmpdir: %v", names)
+		}
+
+		removeAll(topTmpdir)
+	}
+
+	os.Exit(r)
+}
+
+func isAlpineLinux() bool {
+	if runtime.GOOS != "linux" {
+		return false
+	}
+	fi, err := os.Lstat("/etc/alpine-release")
+	return err == nil && fi.Mode().IsRegular()
+}
+
+// The length of an mtime tick on this system. This is an estimate of
+// how long we need to sleep to ensure that the mtime of two files is
+// different.
+// We used to try to be clever but that didn't always work (see golang.org/issue/12205).
+var mtimeTick time.Duration = 1 * time.Second
+
+// Manage a single run of the testgo binary.
+type testgoData struct {
+	t              *testing.T
+	temps          []string
+	env            []string
+	tempdir        string
+	ran            bool
+	inParallel     bool
+	stdout, stderr bytes.Buffer
+	execDir        string // dir for tg.run
+}
+
+// skipIfGccgo skips the test if using gccgo.
+func skipIfGccgo(t *testing.T, msg string) {
+	if runtime.Compiler == "gccgo" {
+		t.Skipf("skipping test not supported on gccgo: %s", msg)
+	}
+}
+
+// testgo sets up for a test that runs testgo.
+func testgo(t *testing.T) *testgoData {
+	t.Helper()
+	testenv.MustHaveGoBuild(t)
+	testenv.SkipIfShortAndSlow(t)
+
+	return &testgoData{t: t}
+}
+
+// must gives a fatal error if err is not nil.
+func (tg *testgoData) must(err error) {
+	tg.t.Helper()
+	if err != nil {
+		tg.t.Fatal(err)
+	}
+}
+
+// check gives a test non-fatal error if err is not nil.
+func (tg *testgoData) check(err error) {
+	tg.t.Helper()
+	if err != nil {
+		tg.t.Error(err)
+	}
+}
+
+// parallel runs the test in parallel by calling t.Parallel.
+func (tg *testgoData) parallel() {
+	tg.t.Helper()
+	if tg.ran {
+		tg.t.Fatal("internal testsuite error: call to parallel after run")
+	}
+	for _, e := range tg.env {
+		if strings.HasPrefix(e, "GOROOT=") || strings.HasPrefix(e, "GOPATH=") || strings.HasPrefix(e, "GOBIN=") {
+			val := e[strings.Index(e, "=")+1:]
+			if strings.HasPrefix(val, "testdata") || strings.HasPrefix(val, "./testdata") {
+				tg.t.Fatalf("internal testsuite error: call to parallel with testdata in environment (%s)", e)
+			}
+		}
+	}
+	tg.inParallel = true
+	tg.t.Parallel()
+}
+
+// pwd returns the current directory.
+func (tg *testgoData) pwd() string {
+	tg.t.Helper()
+	wd, err := os.Getwd()
+	if err != nil {
+		tg.t.Fatalf("could not get working directory: %v", err)
+	}
+	return wd
+}
+
+// sleep sleeps for one tick, where a tick is a conservative estimate
+// of how long it takes for a file modification to get a different
+// mtime.
+func (tg *testgoData) sleep() {
+	time.Sleep(mtimeTick)
+}
+
+// setenv sets an environment variable to use when running the test go
+// command.
+func (tg *testgoData) setenv(name, val string) {
+	tg.t.Helper()
+	if tg.inParallel && (name == "GOROOT" || name == "GOPATH" || name == "GOBIN") && (strings.HasPrefix(val, "testdata") || strings.HasPrefix(val, "./testdata")) {
+		tg.t.Fatalf("internal testsuite error: call to setenv with testdata (%s=%s) after parallel", name, val)
+	}
+	tg.unsetenv(name)
+	tg.env = append(tg.env, name+"="+val)
+}
+
+// unsetenv removes an environment variable.
+func (tg *testgoData) unsetenv(name string) {
+	if tg.env == nil {
+		tg.env = append([]string(nil), os.Environ()...)
+		tg.env = append(tg.env, "GO111MODULE=off")
+	}
+	for i, v := range tg.env {
+		if strings.HasPrefix(v, name+"=") {
+			tg.env = append(tg.env[:i], tg.env[i+1:]...)
+			break
+		}
+	}
+}
+
+func (tg *testgoData) goTool() string {
+	return testGo
+}
+
+// doRun runs the test go command, recording stdout and stderr and
+// returning exit status.
+func (tg *testgoData) doRun(args []string) error {
+	tg.t.Helper()
+	if tg.inParallel {
+		for _, arg := range args {
+			if strings.HasPrefix(arg, "testdata") || strings.HasPrefix(arg, "./testdata") {
+				tg.t.Fatal("internal testsuite error: parallel run using testdata")
+			}
+		}
+	}
+
+	hasGoroot := false
+	for _, v := range tg.env {
+		if strings.HasPrefix(v, "GOROOT=") {
+			hasGoroot = true
+			break
+		}
+	}
+	prog := tg.goTool()
+	if !hasGoroot {
+		tg.setenv("GOROOT", testGOROOT)
+	}
+
+	tg.t.Logf("running testgo %v", args)
+	cmd := exec.Command(prog, args...)
+	tg.stdout.Reset()
+	tg.stderr.Reset()
+	cmd.Dir = tg.execDir
+	cmd.Stdout = &tg.stdout
+	cmd.Stderr = &tg.stderr
+	cmd.Env = tg.env
+	status := cmd.Run()
+	if tg.stdout.Len() > 0 {
+		tg.t.Log("standard output:")
+		tg.t.Log(tg.stdout.String())
+	}
+	if tg.stderr.Len() > 0 {
+		tg.t.Log("standard error:")
+		tg.t.Log(tg.stderr.String())
+	}
+	tg.ran = true
+	return status
+}
+
+// run runs the test go command, and expects it to succeed.
+func (tg *testgoData) run(args ...string) {
+	tg.t.Helper()
+	if status := tg.doRun(args); status != nil {
+		wd, _ := os.Getwd()
+		tg.t.Logf("go %v failed unexpectedly in %s: %v", args, wd, status)
+		tg.t.FailNow()
+	}
+}
+
+// runFail runs the test go command, and expects it to fail.
+func (tg *testgoData) runFail(args ...string) {
+	tg.t.Helper()
+	if status := tg.doRun(args); status == nil {
+		tg.t.Fatal("testgo succeeded unexpectedly")
+	} else {
+		tg.t.Log("testgo failed as expected:", status)
+	}
+}
+
+// runGit runs a git command, and expects it to succeed.
+func (tg *testgoData) runGit(dir string, args ...string) {
+	tg.t.Helper()
+	cmd := exec.Command("git", args...)
+	tg.stdout.Reset()
+	tg.stderr.Reset()
+	cmd.Stdout = &tg.stdout
+	cmd.Stderr = &tg.stderr
+	cmd.Dir = dir
+	cmd.Env = tg.env
+	status := cmd.Run()
+	if tg.stdout.Len() > 0 {
+		tg.t.Log("git standard output:")
+		tg.t.Log(tg.stdout.String())
+	}
+	if tg.stderr.Len() > 0 {
+		tg.t.Log("git standard error:")
+		tg.t.Log(tg.stderr.String())
+	}
+	if status != nil {
+		tg.t.Logf("git %v failed unexpectedly: %v", args, status)
+		tg.t.FailNow()
+	}
+}
+
+// getStdout returns standard output of the testgo run as a string.
+func (tg *testgoData) getStdout() string {
+	tg.t.Helper()
+	if !tg.ran {
+		tg.t.Fatal("internal testsuite error: stdout called before run")
+	}
+	return tg.stdout.String()
+}
+
+// getStderr returns standard error of the testgo run as a string.
+func (tg *testgoData) getStderr() string {
+	tg.t.Helper()
+	if !tg.ran {
+		tg.t.Fatal("internal testsuite error: stdout called before run")
+	}
+	return tg.stderr.String()
+}
+
+// doGrepMatch looks for a regular expression in a buffer, and returns
+// whether it is found. The regular expression is matched against
+// each line separately, as with the grep command.
+func (tg *testgoData) doGrepMatch(match string, b *bytes.Buffer) bool {
+	tg.t.Helper()
+	if !tg.ran {
+		tg.t.Fatal("internal testsuite error: grep called before run")
+	}
+	re := regexp.MustCompile(match)
+	for _, ln := range bytes.Split(b.Bytes(), []byte{'\n'}) {
+		if re.Match(ln) {
+			return true
+		}
+	}
+	return false
+}
+
+// doGrep looks for a regular expression in a buffer and fails if it
+// is not found. The name argument is the name of the output we are
+// searching, "output" or "error". The msg argument is logged on
+// failure.
+func (tg *testgoData) doGrep(match string, b *bytes.Buffer, name, msg string) {
+	tg.t.Helper()
+	if !tg.doGrepMatch(match, b) {
+		tg.t.Log(msg)
+		tg.t.Logf("pattern %v not found in standard %s", match, name)
+		tg.t.FailNow()
+	}
+}
+
+// grepStdout looks for a regular expression in the test run's
+// standard output and fails, logging msg, if it is not found.
+func (tg *testgoData) grepStdout(match, msg string) {
+	tg.t.Helper()
+	tg.doGrep(match, &tg.stdout, "output", msg)
+}
+
+// grepStderr looks for a regular expression in the test run's
+// standard error and fails, logging msg, if it is not found.
+func (tg *testgoData) grepStderr(match, msg string) {
+	tg.t.Helper()
+	tg.doGrep(match, &tg.stderr, "error", msg)
+}
+
+// grepBoth looks for a regular expression in the test run's standard
+// output or stand error and fails, logging msg, if it is not found.
+func (tg *testgoData) grepBoth(match, msg string) {
+	tg.t.Helper()
+	if !tg.doGrepMatch(match, &tg.stdout) && !tg.doGrepMatch(match, &tg.stderr) {
+		tg.t.Log(msg)
+		tg.t.Logf("pattern %v not found in standard output or standard error", match)
+		tg.t.FailNow()
+	}
+}
+
+// doGrepNot looks for a regular expression in a buffer and fails if
+// it is found. The name and msg arguments are as for doGrep.
+func (tg *testgoData) doGrepNot(match string, b *bytes.Buffer, name, msg string) {
+	tg.t.Helper()
+	if tg.doGrepMatch(match, b) {
+		tg.t.Log(msg)
+		tg.t.Logf("pattern %v found unexpectedly in standard %s", match, name)
+		tg.t.FailNow()
+	}
+}
+
+// grepStdoutNot looks for a regular expression in the test run's
+// standard output and fails, logging msg, if it is found.
+func (tg *testgoData) grepStdoutNot(match, msg string) {
+	tg.t.Helper()
+	tg.doGrepNot(match, &tg.stdout, "output", msg)
+}
+
+// grepStderrNot looks for a regular expression in the test run's
+// standard error and fails, logging msg, if it is found.
+func (tg *testgoData) grepStderrNot(match, msg string) {
+	tg.t.Helper()
+	tg.doGrepNot(match, &tg.stderr, "error", msg)
+}
+
+// grepBothNot looks for a regular expression in the test run's
+// standard output or standard error and fails, logging msg, if it is
+// found.
+func (tg *testgoData) grepBothNot(match, msg string) {
+	tg.t.Helper()
+	if tg.doGrepMatch(match, &tg.stdout) || tg.doGrepMatch(match, &tg.stderr) {
+		tg.t.Log(msg)
+		tg.t.Fatalf("pattern %v found unexpectedly in standard output or standard error", match)
+	}
+}
+
+// doGrepCount counts the number of times a regexp is seen in a buffer.
+func (tg *testgoData) doGrepCount(match string, b *bytes.Buffer) int {
+	tg.t.Helper()
+	if !tg.ran {
+		tg.t.Fatal("internal testsuite error: doGrepCount called before run")
+	}
+	re := regexp.MustCompile(match)
+	c := 0
+	for _, ln := range bytes.Split(b.Bytes(), []byte{'\n'}) {
+		if re.Match(ln) {
+			c++
+		}
+	}
+	return c
+}
+
+// grepCountBoth returns the number of times a regexp is seen in both
+// standard output and standard error.
+func (tg *testgoData) grepCountBoth(match string) int {
+	tg.t.Helper()
+	return tg.doGrepCount(match, &tg.stdout) + tg.doGrepCount(match, &tg.stderr)
+}
+
+// creatingTemp records that the test plans to create a temporary file
+// or directory. If the file or directory exists already, it will be
+// removed. When the test completes, the file or directory will be
+// removed if it exists.
+func (tg *testgoData) creatingTemp(path string) {
+	tg.t.Helper()
+	if filepath.IsAbs(path) && !strings.HasPrefix(path, tg.tempdir) {
+		tg.t.Fatalf("internal testsuite error: creatingTemp(%q) with absolute path not in temporary directory", path)
+	}
+	tg.must(robustio.RemoveAll(path))
+	tg.temps = append(tg.temps, path)
+}
+
+// makeTempdir makes a temporary directory for a run of testgo. If
+// the temporary directory was already created, this does nothing.
+func (tg *testgoData) makeTempdir() {
+	tg.t.Helper()
+	if tg.tempdir == "" {
+		var err error
+		tg.tempdir, err = os.MkdirTemp("", "gotest")
+		tg.must(err)
+	}
+}
+
+// tempFile adds a temporary file for a run of testgo.
+func (tg *testgoData) tempFile(path, contents string) {
+	tg.t.Helper()
+	tg.makeTempdir()
+	tg.must(os.MkdirAll(filepath.Join(tg.tempdir, filepath.Dir(path)), 0755))
+	bytes := []byte(contents)
+	if strings.HasSuffix(path, ".go") {
+		formatted, err := format.Source(bytes)
+		if err == nil {
+			bytes = formatted
+		}
+	}
+	tg.must(os.WriteFile(filepath.Join(tg.tempdir, path), bytes, 0644))
+}
+
+// tempDir adds a temporary directory for a run of testgo.
+func (tg *testgoData) tempDir(path string) {
+	tg.t.Helper()
+	tg.makeTempdir()
+	if err := os.MkdirAll(filepath.Join(tg.tempdir, path), 0755); err != nil && !os.IsExist(err) {
+		tg.t.Fatal(err)
+	}
+}
+
+// path returns the absolute pathname to file with the temporary
+// directory.
+func (tg *testgoData) path(name string) string {
+	tg.t.Helper()
+	if tg.tempdir == "" {
+		tg.t.Fatalf("internal testsuite error: path(%q) with no tempdir", name)
+	}
+	if name == "." {
+		return tg.tempdir
+	}
+	return filepath.Join(tg.tempdir, name)
+}
+
+// mustExist fails if path does not exist.
+func (tg *testgoData) mustExist(path string) {
+	tg.t.Helper()
+	if _, err := os.Stat(path); err != nil {
+		if os.IsNotExist(err) {
+			tg.t.Fatalf("%s does not exist but should", path)
+		}
+		tg.t.Fatalf("%s stat failed: %v", path, err)
+	}
+}
+
+// mustNotExist fails if path exists.
+func (tg *testgoData) mustNotExist(path string) {
+	tg.t.Helper()
+	if _, err := os.Stat(path); err == nil || !os.IsNotExist(err) {
+		tg.t.Fatalf("%s exists but should not (%v)", path, err)
+	}
+}
+
+// mustHaveContent succeeds if filePath is a path to a file,
+// and that file is readable and not empty.
+func (tg *testgoData) mustHaveContent(filePath string) {
+	tg.mustExist(filePath)
+	f, err := os.Stat(filePath)
+	if err != nil {
+		tg.t.Fatal(err)
+	}
+	if f.Size() == 0 {
+		tg.t.Fatalf("expected %s to have data, but is empty", filePath)
+	}
+}
+
+// wantExecutable fails with msg if path is not executable.
+func (tg *testgoData) wantExecutable(path, msg string) {
+	tg.t.Helper()
+	if st, err := os.Stat(path); err != nil {
+		if !os.IsNotExist(err) {
+			tg.t.Log(err)
+		}
+		tg.t.Fatal(msg)
+	} else {
+		if runtime.GOOS != "windows" && st.Mode()&0111 == 0 {
+			tg.t.Fatalf("binary %s exists but is not executable", path)
+		}
+	}
+}
+
+// isStale reports whether pkg is stale, and why
+func (tg *testgoData) isStale(pkg string) (bool, string) {
+	tg.t.Helper()
+	tg.run("list", "-f", "{{.Stale}}:{{.StaleReason}}", pkg)
+	v := strings.TrimSpace(tg.getStdout())
+	f := strings.SplitN(v, ":", 2)
+	if len(f) == 2 {
+		switch f[0] {
+		case "true":
+			return true, f[1]
+		case "false":
+			return false, f[1]
+		}
+	}
+	tg.t.Fatalf("unexpected output checking staleness of package %v: %v", pkg, v)
+	panic("unreachable")
+}
+
+// wantStale fails with msg if pkg is not stale.
+func (tg *testgoData) wantStale(pkg, reason, msg string) {
+	tg.t.Helper()
+	stale, why := tg.isStale(pkg)
+	if !stale {
+		tg.t.Fatal(msg)
+	}
+	// We always accept the reason as being "not installed but
+	// available in build cache", because when that is the case go
+	// list doesn't try to sort out the underlying reason why the
+	// package is not installed.
+	if reason == "" && why != "" || !strings.Contains(why, reason) && !strings.Contains(why, "not installed but available in build cache") {
+		tg.t.Errorf("wrong reason for Stale=true: %q, want %q", why, reason)
+	}
+}
+
+// wantNotStale fails with msg if pkg is stale.
+func (tg *testgoData) wantNotStale(pkg, reason, msg string) {
+	tg.t.Helper()
+	stale, why := tg.isStale(pkg)
+	if stale {
+		tg.t.Fatal(msg)
+	}
+	if reason == "" && why != "" || !strings.Contains(why, reason) {
+		tg.t.Errorf("wrong reason for Stale=false: %q, want %q", why, reason)
+	}
+}
+
+// If -testwork is specified, the test prints the name of the temp directory
+// and does not remove it when done, so that a programmer can
+// poke at the test file tree afterward.
+var testWork = flag.Bool("testwork", false, "")
+
+// cleanup cleans up a test that runs testgo.
+func (tg *testgoData) cleanup() {
+	tg.t.Helper()
+	if *testWork {
+		tg.t.Logf("TESTWORK=%s\n", tg.path("."))
+		return
+	}
+	for _, path := range tg.temps {
+		tg.check(removeAll(path))
+	}
+	if tg.tempdir != "" {
+		tg.check(removeAll(tg.tempdir))
+	}
+}
+
+func removeAll(dir string) error {
+	// module cache has 0444 directories;
+	// make them writable in order to remove content.
+	filepath.WalkDir(dir, func(path string, info fs.DirEntry, err error) error {
+		// chmod not only directories, but also things that we couldn't even stat
+		// due to permission errors: they may also be unreadable directories.
+		if err != nil || info.IsDir() {
+			os.Chmod(path, 0777)
+		}
+		return nil
+	})
+	return robustio.RemoveAll(dir)
+}
+
+// failSSH puts an ssh executable in the PATH that always fails.
+// This is to stub out uses of ssh by go get.
+func (tg *testgoData) failSSH() {
+	tg.t.Helper()
+	wd, err := os.Getwd()
+	if err != nil {
+		tg.t.Fatal(err)
+	}
+	fail := filepath.Join(wd, "testdata/failssh")
+	tg.setenv("PATH", fmt.Sprintf("%v%c%v", fail, filepath.ListSeparator, os.Getenv("PATH")))
+}
+
+func TestNewReleaseRebuildsStalePackagesInGOPATH(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping lengthy test in short mode")
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	// Copy the runtime packages into a temporary GOROOT
+	// so that we can change files.
+	for _, copydir := range []string{
+		"src/runtime",
+		"src/internal/abi",
+		"src/internal/bytealg",
+		"src/internal/cpu",
+		"src/internal/goarch",
+		"src/internal/goexperiment",
+		"src/internal/goos",
+		"src/math/bits",
+		"src/unsafe",
+		filepath.Join("pkg", runtime.GOOS+"_"+runtime.GOARCH),
+		filepath.Join("pkg/tool", runtime.GOOS+"_"+runtime.GOARCH),
+		"pkg/include",
+	} {
+		srcdir := filepath.Join(testGOROOT, copydir)
+		tg.tempDir(filepath.Join("goroot", copydir))
+		err := filepath.WalkDir(srcdir,
+			func(path string, info fs.DirEntry, err error) error {
+				if err != nil {
+					return err
+				}
+				if info.IsDir() {
+					return nil
+				}
+				srcrel, err := filepath.Rel(srcdir, path)
+				if err != nil {
+					return err
+				}
+				dest := filepath.Join("goroot", copydir, srcrel)
+				data, err := os.ReadFile(path)
+				if err != nil {
+					return err
+				}
+				tg.tempFile(dest, string(data))
+				if strings.Contains(copydir, filepath.Join("pkg", "tool")) {
+					os.Chmod(tg.path(dest), 0777)
+				}
+				return nil
+			})
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+	tg.setenv("GOROOT", tg.path("goroot"))
+
+	addVar := func(name string, idx int) (restore func()) {
+		data, err := os.ReadFile(name)
+		if err != nil {
+			t.Fatal(err)
+		}
+		old := data
+		data = append(data, fmt.Sprintf("var DummyUnusedVar%d bool\n", idx)...)
+		if err := os.WriteFile(name, append(data, '\n'), 0666); err != nil {
+			t.Fatal(err)
+		}
+		tg.sleep()
+		return func() {
+			if err := os.WriteFile(name, old, 0666); err != nil {
+				t.Fatal(err)
+			}
+		}
+	}
+
+	// Every main package depends on the "runtime".
+	tg.tempFile("d1/src/p1/p1.go", `package main; func main(){}`)
+	tg.setenv("GOPATH", tg.path("d1"))
+	// Pass -i flag to rebuild everything outdated.
+	tg.run("install", "-i", "p1")
+	tg.wantNotStale("p1", "", "./testgo list claims p1 is stale, incorrectly, before any changes")
+
+	// Changing mtime of runtime/internal/sys/sys.go
+	// should have no effect: only the content matters.
+	// In fact this should be true even outside a release branch.
+	sys := tg.path("goroot/src/runtime/internal/sys/sys.go")
+	tg.sleep()
+	restore := addVar(sys, 0)
+	restore()
+	tg.wantNotStale("p1", "", "./testgo list claims p1 is stale, incorrectly, after updating mtime of runtime/internal/sys/sys.go")
+
+	// But changing content of any file should have an effect.
+	// Previously zversion.go was the only one that mattered;
+	// now they all matter, so keep using sys.go.
+	restore = addVar(sys, 1)
+	defer restore()
+	tg.wantStale("p1", "stale dependency: runtime/internal/sys", "./testgo list claims p1 is NOT stale, incorrectly, after changing sys.go")
+	restore()
+	tg.wantNotStale("p1", "", "./testgo list claims p1 is stale, incorrectly, after changing back to old release")
+	addVar(sys, 2)
+	tg.wantStale("p1", "stale dependency: runtime", "./testgo list claims p1 is NOT stale, incorrectly, after changing sys.go again")
+	tg.run("install", "-i", "p1")
+	tg.wantNotStale("p1", "", "./testgo list claims p1 is stale after building with new release")
+
+	// Restore to "old" release.
+	restore()
+	tg.wantStale("p1", "stale dependency: runtime/internal/sys", "./testgo list claims p1 is NOT stale, incorrectly, after restoring sys.go")
+	tg.run("install", "-i", "p1")
+	tg.wantNotStale("p1", "", "./testgo list claims p1 is stale after building with old release")
+}
+
+// cmd/go: custom import path checking should not apply to Go packages without import comment.
+func TestIssue10952(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+	testenv.MustHaveExecPath(t, "git")
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempDir("src")
+	tg.setenv("GOPATH", tg.path("."))
+	const importPath = "github.com/zombiezen/go-get-issue-10952"
+	tg.run("get", "-d", "-u", importPath)
+	repoDir := tg.path("src/" + importPath)
+	tg.runGit(repoDir, "remote", "set-url", "origin", "https://"+importPath+".git")
+	tg.run("get", "-d", "-u", importPath)
+}
+
+func TestIssue16471(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+	testenv.MustHaveExecPath(t, "git")
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempDir("src")
+	tg.setenv("GOPATH", tg.path("."))
+	tg.must(os.MkdirAll(tg.path("src/rsc.io/go-get-issue-10952"), 0755))
+	tg.runGit(tg.path("src/rsc.io"), "clone", "https://github.com/zombiezen/go-get-issue-10952")
+	tg.runFail("get", "-u", "rsc.io/go-get-issue-10952")
+	tg.grepStderr("rsc.io/go-get-issue-10952 is a custom import path for https://github.com/rsc/go-get-issue-10952, but .* is checked out from https://github.com/zombiezen/go-get-issue-10952", "did not detect updated import path")
+}
+
+// Test git clone URL that uses SCP-like syntax and custom import path checking.
+func TestIssue11457(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+	testenv.MustHaveExecPath(t, "git")
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempDir("src")
+	tg.setenv("GOPATH", tg.path("."))
+	const importPath = "rsc.io/go-get-issue-11457"
+	tg.run("get", "-d", "-u", importPath)
+	repoDir := tg.path("src/" + importPath)
+	tg.runGit(repoDir, "remote", "set-url", "origin", "git@github.com:rsc/go-get-issue-11457")
+
+	// At this time, custom import path checking compares remotes verbatim (rather than
+	// just the host and path, skipping scheme and user), so we expect go get -u to fail.
+	// However, the goal of this test is to verify that gitRemoteRepo correctly parsed
+	// the SCP-like syntax, and we expect it to appear in the error message.
+	tg.runFail("get", "-d", "-u", importPath)
+	want := " is checked out from ssh://git@github.com/rsc/go-get-issue-11457"
+	if !strings.HasSuffix(strings.TrimSpace(tg.getStderr()), want) {
+		t.Error("expected clone URL to appear in stderr")
+	}
+}
+
+func TestGetGitDefaultBranch(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+	testenv.MustHaveExecPath(t, "git")
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempDir("src")
+	tg.setenv("GOPATH", tg.path("."))
+
+	// This repo has two branches, master and another-branch.
+	// The another-branch is the default that you get from 'git clone'.
+	// The go get command variants should not override this.
+	const importPath = "github.com/rsc/go-get-default-branch"
+
+	tg.run("get", "-d", importPath)
+	repoDir := tg.path("src/" + importPath)
+	tg.runGit(repoDir, "branch", "--contains", "HEAD")
+	tg.grepStdout(`\* another-branch`, "not on correct default branch")
+
+	tg.run("get", "-d", "-u", importPath)
+	tg.runGit(repoDir, "branch", "--contains", "HEAD")
+	tg.grepStdout(`\* another-branch`, "not on correct default branch")
+}
+
+// Security issue. Don't disable. See golang.org/issue/22125.
+func TestAccidentalGitCheckout(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+	testenv.MustHaveExecPath(t, "git")
+	testenv.MustHaveExecPath(t, "svn")
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempDir("src")
+
+	tg.setenv("GOPATH", tg.path("."))
+
+	tg.runFail("get", "-u", "vcs-test.golang.org/go/test1-svn-git")
+	tg.grepStderr("src[\\\\/]vcs-test.* uses git, but parent .*src[\\\\/]vcs-test.* uses svn", "get did not fail for right reason")
+
+	if _, err := os.Stat(tg.path("SrC")); err == nil {
+		// This case only triggers on a case-insensitive file system.
+		tg.runFail("get", "-u", "vcs-test.golang.org/go/test2-svn-git/test2main")
+		tg.grepStderr("src[\\\\/]vcs-test.* uses git, but parent .*src[\\\\/]vcs-test.* uses svn", "get did not fail for right reason")
+	}
+}
+
+func TestPackageMainTestCompilerFlags(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOPATH", tg.path("."))
+	tg.tempFile("src/p1/p1.go", "package main\n")
+	tg.tempFile("src/p1/p1_test.go", "package main\nimport \"testing\"\nfunc Test(t *testing.T){}\n")
+	tg.run("test", "-c", "-n", "p1")
+	tg.grepBothNot(`([\\/]compile|gccgo).* (-p main|-fgo-pkgpath=main).*p1\.go`, "should not have run compile -p main p1.go")
+	tg.grepStderr(`([\\/]compile|gccgo).* (-p p1|-fgo-pkgpath=p1).*p1\.go`, "should have run compile -p p1 p1.go")
+}
+
+// Issue 4104.
+func TestGoTestWithPackageListedMultipleTimes(t *testing.T) {
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.run("test", "errors", "errors", "errors", "errors", "errors")
+	if strings.Contains(strings.TrimSpace(tg.getStdout()), "\n") {
+		t.Error("go test errors errors errors errors errors tested the same package multiple times")
+	}
+}
+
+func TestGoListHasAConsistentOrder(t *testing.T) {
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.run("list", "std")
+	first := tg.getStdout()
+	tg.run("list", "std")
+	if first != tg.getStdout() {
+		t.Error("go list std ordering is inconsistent")
+	}
+}
+
+func TestGoListStdDoesNotIncludeCommands(t *testing.T) {
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.run("list", "std")
+	tg.grepStdoutNot("cmd/", "go list std shows commands")
+}
+
+func TestGoListCmdOnlyShowsCommands(t *testing.T) {
+	skipIfGccgo(t, "gccgo does not have GOROOT")
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.run("list", "cmd")
+	out := strings.TrimSpace(tg.getStdout())
+	for _, line := range strings.Split(out, "\n") {
+		if !strings.Contains(line, "cmd/") {
+			t.Error("go list cmd shows non-commands")
+			break
+		}
+	}
+}
+
+func TestGoListDeps(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempDir("src/p1/p2/p3/p4")
+	tg.setenv("GOPATH", tg.path("."))
+	tg.tempFile("src/p1/p.go", "package p1\nimport _ \"p1/p2\"\n")
+	tg.tempFile("src/p1/p2/p.go", "package p2\nimport _ \"p1/p2/p3\"\n")
+	tg.tempFile("src/p1/p2/p3/p.go", "package p3\nimport _ \"p1/p2/p3/p4\"\n")
+	tg.tempFile("src/p1/p2/p3/p4/p.go", "package p4\n")
+	tg.run("list", "-f", "{{.Deps}}", "p1")
+	tg.grepStdout("p1/p2/p3/p4", "Deps(p1) does not mention p4")
+
+	tg.run("list", "-deps", "p1")
+	tg.grepStdout("p1/p2/p3/p4", "-deps p1 does not mention p4")
+
+	if runtime.Compiler != "gccgo" {
+		// Check the list is in dependency order.
+		tg.run("list", "-deps", "math")
+		want := "internal/cpu\nunsafe\nmath/bits\nmath\n"
+		out := tg.stdout.String()
+		if !strings.Contains(out, "internal/cpu") {
+			// Some systems don't use internal/cpu.
+			want = "unsafe\nmath/bits\nmath\n"
+		}
+		if tg.stdout.String() != want {
+			t.Fatalf("list -deps math: wrong order\nhave %q\nwant %q", tg.stdout.String(), want)
+		}
+	}
+}
+
+func TestGoListTest(t *testing.T) {
+	skipIfGccgo(t, "gccgo does not have standard packages")
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOCACHE", tg.tempdir)
+
+	tg.run("list", "-test", "-deps", "sort")
+	tg.grepStdout(`^sort.test$`, "missing test main")
+	tg.grepStdout(`^sort$`, "missing real sort")
+	tg.grepStdout(`^sort \[sort.test\]$`, "missing test copy of sort")
+	tg.grepStdout(`^testing \[sort.test\]$`, "missing test copy of testing")
+	tg.grepStdoutNot(`^testing$`, "unexpected real copy of testing")
+
+	tg.run("list", "-test", "sort")
+	tg.grepStdout(`^sort.test$`, "missing test main")
+	tg.grepStdout(`^sort$`, "missing real sort")
+	tg.grepStdout(`^sort \[sort.test\]$`, "unexpected test copy of sort")
+	tg.grepStdoutNot(`^testing \[sort.test\]$`, "unexpected test copy of testing")
+	tg.grepStdoutNot(`^testing$`, "unexpected real copy of testing")
+
+	tg.run("list", "-test", "cmd/buildid", "cmd/doc")
+	tg.grepStdout(`^cmd/buildid$`, "missing cmd/buildid")
+	tg.grepStdout(`^cmd/doc$`, "missing cmd/doc")
+	tg.grepStdout(`^cmd/doc\.test$`, "missing cmd/doc test")
+	tg.grepStdoutNot(`^cmd/buildid\.test$`, "unexpected cmd/buildid test")
+	tg.grepStdoutNot(`^testing`, "unexpected testing")
+
+	tg.run("list", "-test", "runtime/cgo")
+	tg.grepStdout(`^runtime/cgo$`, "missing runtime/cgo")
+
+	tg.run("list", "-deps", "-f", "{{if .DepOnly}}{{.ImportPath}}{{end}}", "sort")
+	tg.grepStdout(`^internal/reflectlite$`, "missing internal/reflectlite")
+	tg.grepStdoutNot(`^sort`, "unexpected sort")
+}
+
+func TestGoListCompiledCgo(t *testing.T) {
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOCACHE", tg.tempdir)
+
+	tg.run("list", "-f", `{{join .CgoFiles "\n"}}`, "net")
+	if tg.stdout.String() == "" {
+		t.Skip("net does not use cgo")
+	}
+	if strings.Contains(tg.stdout.String(), tg.tempdir) {
+		t.Fatalf(".CgoFiles unexpectedly mentioned cache %s", tg.tempdir)
+	}
+	tg.run("list", "-compiled", "-f", `{{.Dir}}{{"\n"}}{{join .CompiledGoFiles "\n"}}`, "net")
+	if !strings.Contains(tg.stdout.String(), tg.tempdir) {
+		t.Fatalf(".CompiledGoFiles with -compiled did not mention cache %s", tg.tempdir)
+	}
+	dir := ""
+	for _, file := range strings.Split(tg.stdout.String(), "\n") {
+		if file == "" {
+			continue
+		}
+		if dir == "" {
+			dir = file
+			continue
+		}
+		if !strings.Contains(file, "/") && !strings.Contains(file, `\`) {
+			file = filepath.Join(dir, file)
+		}
+		if _, err := os.Stat(file); err != nil {
+			t.Fatalf("cannot find .CompiledGoFiles result %s: %v", file, err)
+		}
+	}
+}
+
+func TestGoListExport(t *testing.T) {
+	skipIfGccgo(t, "gccgo does not have standard packages")
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOCACHE", tg.tempdir)
+
+	tg.run("list", "-f", "{{.Export}}", "strings")
+	if tg.stdout.String() != "" {
+		t.Fatalf(".Export without -export unexpectedly set")
+	}
+	tg.run("list", "-export", "-f", "{{.Export}}", "strings")
+	file := strings.TrimSpace(tg.stdout.String())
+	if file == "" {
+		t.Fatalf(".Export with -export was empty")
+	}
+	if _, err := os.Stat(file); err != nil {
+		t.Fatalf("cannot find .Export result %s: %v", file, err)
+	}
+
+	tg.run("list", "-export", "-f", "{{.BuildID}}", "strings")
+	buildID := strings.TrimSpace(tg.stdout.String())
+	if buildID == "" {
+		t.Fatalf(".BuildID with -export was empty")
+	}
+
+	tg.run("tool", "buildid", file)
+	toolBuildID := strings.TrimSpace(tg.stdout.String())
+	if buildID != toolBuildID {
+		t.Fatalf(".BuildID with -export %q disagrees with 'go tool buildid' %q", buildID, toolBuildID)
+	}
+}
+
+// Issue 4096. Validate the output of unsuccessful go install foo/quxx.
+func TestUnsuccessfulGoInstallShouldMentionMissingPackage(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.runFail("install", "foo/quxx")
+	if tg.grepCountBoth(`cannot find package "foo/quxx" in any of`) != 1 {
+		t.Error(`go install foo/quxx expected error: .*cannot find package "foo/quxx" in any of`)
+	}
+}
+
+func TestGOROOTSearchFailureReporting(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.runFail("install", "foo/quxx")
+	if tg.grepCountBoth(regexp.QuoteMeta(filepath.Join("foo", "quxx"))+` \(from \$GOROOT\)$`) != 1 {
+		t.Error(`go install foo/quxx expected error: .*foo/quxx (from $GOROOT)`)
+	}
+}
+
+func TestMultipleGOPATHEntriesReportedSeparately(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	sep := string(filepath.ListSeparator)
+	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata", "a")+sep+filepath.Join(tg.pwd(), "testdata", "b"))
+	tg.runFail("install", "foo/quxx")
+	if tg.grepCountBoth(`testdata[/\\].[/\\]src[/\\]foo[/\\]quxx`) != 2 {
+		t.Error(`go install foo/quxx expected error: .*testdata/a/src/foo/quxx (from $GOPATH)\n.*testdata/b/src/foo/quxx`)
+	}
+}
+
+// Test (from $GOPATH) annotation is reported for the first GOPATH entry,
+func TestMentionGOPATHInFirstGOPATHEntry(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	sep := string(filepath.ListSeparator)
+	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata", "a")+sep+filepath.Join(tg.pwd(), "testdata", "b"))
+	tg.runFail("install", "foo/quxx")
+	if tg.grepCountBoth(regexp.QuoteMeta(filepath.Join("testdata", "a", "src", "foo", "quxx"))+` \(from \$GOPATH\)$`) != 1 {
+		t.Error(`go install foo/quxx expected error: .*testdata/a/src/foo/quxx (from $GOPATH)`)
+	}
+}
+
+// but not on the second.
+func TestMentionGOPATHNotOnSecondEntry(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	sep := string(filepath.ListSeparator)
+	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata", "a")+sep+filepath.Join(tg.pwd(), "testdata", "b"))
+	tg.runFail("install", "foo/quxx")
+	if tg.grepCountBoth(regexp.QuoteMeta(filepath.Join("testdata", "b", "src", "foo", "quxx"))+`$`) != 1 {
+		t.Error(`go install foo/quxx expected error: .*testdata/b/src/foo/quxx`)
+	}
+}
+
+func homeEnvName() string {
+	switch runtime.GOOS {
+	case "windows":
+		return "USERPROFILE"
+	case "plan9":
+		return "home"
+	default:
+		return "HOME"
+	}
+}
+
+func tempEnvName() string {
+	switch runtime.GOOS {
+	case "windows":
+		return "TMP"
+	case "plan9":
+		return "TMPDIR" // actually plan 9 doesn't have one at all but this is fine
+	default:
+		return "TMPDIR"
+	}
+}
+
+func TestDefaultGOPATH(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempDir("home/go")
+	tg.setenv(homeEnvName(), tg.path("home"))
+
+	tg.run("env", "GOPATH")
+	tg.grepStdout(regexp.QuoteMeta(tg.path("home/go")), "want GOPATH=$HOME/go")
+
+	tg.setenv("GOROOT", tg.path("home/go"))
+	tg.run("env", "GOPATH")
+	tg.grepStdoutNot(".", "want unset GOPATH because GOROOT=$HOME/go")
+
+	tg.setenv("GOROOT", tg.path("home/go")+"/")
+	tg.run("env", "GOPATH")
+	tg.grepStdoutNot(".", "want unset GOPATH because GOROOT=$HOME/go/")
+}
+
+func TestDefaultGOPATHGet(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+	testenv.MustHaveExecPath(t, "git")
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.setenv("GOPATH", "")
+	tg.tempDir("home")
+	tg.setenv(homeEnvName(), tg.path("home"))
+
+	// warn for creating directory
+	tg.run("get", "-v", "github.com/golang/example/hello")
+	tg.grepStderr("created GOPATH="+regexp.QuoteMeta(tg.path("home/go"))+"; see 'go help gopath'", "did not create GOPATH")
+
+	// no warning if directory already exists
+	tg.must(robustio.RemoveAll(tg.path("home/go")))
+	tg.tempDir("home/go")
+	tg.run("get", "github.com/golang/example/hello")
+	tg.grepStderrNot(".", "expected no output on standard error")
+
+	// error if $HOME/go is a file
+	tg.must(robustio.RemoveAll(tg.path("home/go")))
+	tg.tempFile("home/go", "")
+	tg.runFail("get", "github.com/golang/example/hello")
+	tg.grepStderr(`mkdir .*[/\\]go: .*(not a directory|cannot find the path)`, "expected error because $HOME/go is a file")
+}
+
+func TestDefaultGOPATHPrintedSearchList(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.setenv("GOPATH", "")
+	tg.tempDir("home")
+	tg.setenv(homeEnvName(), tg.path("home"))
+
+	tg.runFail("install", "github.com/golang/example/hello")
+	tg.grepStderr(regexp.QuoteMeta(tg.path("home/go/src/github.com/golang/example/hello"))+`.*from \$GOPATH`, "expected default GOPATH")
+}
+
+func TestLdflagsArgumentsWithSpacesIssue3941(t *testing.T) {
+	skipIfGccgo(t, "gccgo does not support -ldflags -X")
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("main.go", `package main
+		var extern string
+		func main() {
+			println(extern)
+		}`)
+	tg.run("run", "-ldflags", `-X "main.extern=hello world"`, tg.path("main.go"))
+	tg.grepStderr("^hello world", `ldflags -X "main.extern=hello world"' failed`)
+}
+
+func TestLdFlagsLongArgumentsIssue42295(t *testing.T) {
+	// Test the extremely long command line arguments that contain '\n' characters
+	// get encoded and passed correctly.
+	skipIfGccgo(t, "gccgo does not support -ldflags -X")
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("main.go", `package main
+		var extern string
+		func main() {
+			print(extern)
+		}`)
+	testStr := "test test test test test \n\\ "
+	var buf bytes.Buffer
+	for buf.Len() < sys.ExecArgLengthLimit+1 {
+		buf.WriteString(testStr)
+	}
+	tg.run("run", "-ldflags", fmt.Sprintf(`-X "main.extern=%s"`, buf.String()), tg.path("main.go"))
+	if tg.stderr.String() != buf.String() {
+		t.Errorf("strings differ")
+	}
+}
+
+func TestGoTestDashCDashOControlsBinaryLocation(t *testing.T) {
+	skipIfGccgo(t, "gccgo has no standard packages")
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.run("test", "-c", "-o", tg.path("myerrors.test"+exeSuffix), "errors")
+	tg.wantExecutable(tg.path("myerrors.test"+exeSuffix), "go test -c -o myerrors.test did not create myerrors.test")
+}
+
+func TestGoTestDashOWritesBinary(t *testing.T) {
+	skipIfGccgo(t, "gccgo has no standard packages")
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.run("test", "-o", tg.path("myerrors.test"+exeSuffix), "errors")
+	tg.wantExecutable(tg.path("myerrors.test"+exeSuffix), "go test -o myerrors.test did not create myerrors.test")
+}
+
+func TestGoTestDashIDashOWritesBinary(t *testing.T) {
+	skipIfGccgo(t, "gccgo has no standard packages")
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+
+	// don't let test -i overwrite runtime
+	tg.wantNotStale("runtime", "", "must be non-stale before test -i")
+
+	tg.run("test", "-v", "-i", "-o", tg.path("myerrors.test"+exeSuffix), "errors")
+	tg.grepBothNot("PASS|FAIL", "test should not have run")
+	tg.wantExecutable(tg.path("myerrors.test"+exeSuffix), "go test -o myerrors.test did not create myerrors.test")
+}
+
+// Issue 4515.
+func TestInstallWithTags(t *testing.T) {
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempDir("bin")
+	tg.tempFile("src/example/a/main.go", `package main
+		func main() {}`)
+	tg.tempFile("src/example/b/main.go", `// +build mytag
+
+		package main
+		func main() {}`)
+	tg.setenv("GOPATH", tg.path("."))
+	tg.run("install", "-tags", "mytag", "example/a", "example/b")
+	tg.wantExecutable(tg.path("bin/a"+exeSuffix), "go install example/a example/b did not install binaries")
+	tg.wantExecutable(tg.path("bin/b"+exeSuffix), "go install example/a example/b did not install binaries")
+	tg.must(os.Remove(tg.path("bin/a" + exeSuffix)))
+	tg.must(os.Remove(tg.path("bin/b" + exeSuffix)))
+	tg.run("install", "-tags", "mytag", "example/...")
+	tg.wantExecutable(tg.path("bin/a"+exeSuffix), "go install example/... did not install binaries")
+	tg.wantExecutable(tg.path("bin/b"+exeSuffix), "go install example/... did not install binaries")
+	tg.run("list", "-tags", "mytag", "example/b...")
+	if strings.TrimSpace(tg.getStdout()) != "example/b" {
+		t.Error("go list example/b did not find example/b")
+	}
+}
+
+// Issue 17451, 17662.
+func TestSymlinkWarning(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOPATH", tg.path("."))
+
+	tg.tempDir("src/example/xx")
+	tg.tempDir("yy/zz")
+	tg.tempFile("yy/zz/zz.go", "package zz\n")
+	if err := os.Symlink(tg.path("yy"), tg.path("src/example/xx/yy")); err != nil {
+		t.Skipf("symlink failed: %v", err)
+	}
+	tg.run("list", "example/xx/z...")
+	tg.grepStdoutNot(".", "list should not have matched anything")
+	tg.grepStderr("matched no packages", "list should have reported that pattern matched no packages")
+	tg.grepStderrNot("symlink", "list should not have reported symlink")
+
+	tg.run("list", "example/xx/...")
+	tg.grepStdoutNot(".", "list should not have matched anything")
+	tg.grepStderr("matched no packages", "list should have reported that pattern matched no packages")
+	tg.grepStderr("ignoring symlink", "list should have reported symlink")
+}
+
+func TestCgoShowsFullPathNames(t *testing.T) {
+	if !canCgo {
+		t.Skip("skipping because cgo not enabled")
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("src/x/y/dirname/foo.go", `
+		package foo
+		import "C"
+		func f() {`)
+	tg.setenv("GOPATH", tg.path("."))
+	tg.runFail("build", "x/y/dirname")
+	tg.grepBoth("x/y/dirname", "error did not use full path")
+}
+
+func TestCgoHandlesWlORIGIN(t *testing.T) {
+	tooSlow(t)
+	if !canCgo {
+		t.Skip("skipping because cgo not enabled")
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("src/origin/origin.go", `package origin
+		// #cgo !darwin LDFLAGS: -Wl,-rpath,$ORIGIN
+		// void f(void) {}
+		import "C"
+		func f() { C.f() }`)
+	tg.setenv("GOPATH", tg.path("."))
+	tg.run("build", "origin")
+}
+
+func TestCgoPkgConfig(t *testing.T) {
+	tooSlow(t)
+	if !canCgo {
+		t.Skip("skipping because cgo not enabled")
+	}
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	tg.run("env", "PKG_CONFIG")
+	pkgConfig := strings.TrimSpace(tg.getStdout())
+	testenv.MustHaveExecPath(t, pkgConfig)
+	if out, err := exec.Command(pkgConfig, "--atleast-pkgconfig-version", "0.24").CombinedOutput(); err != nil {
+		t.Skipf("%s --atleast-pkgconfig-version 0.24: %v\n%s", pkgConfig, err, out)
+	}
+
+	// OpenBSD's pkg-config is strict about whitespace and only
+	// supports backslash-escaped whitespace. It does not support
+	// quotes, which the normal freedesktop.org pkg-config does
+	// support. See https://man.openbsd.org/pkg-config.1
+	tg.tempFile("foo.pc", `
+Name: foo
+Description: The foo library
+Version: 1.0.0
+Cflags: -Dhello=10 -Dworld=+32 -DDEFINED_FROM_PKG_CONFIG=hello\ world
+`)
+	tg.tempFile("foo.go", `package main
+
+/*
+#cgo pkg-config: foo
+int value() {
+	return DEFINED_FROM_PKG_CONFIG;
+}
+*/
+import "C"
+import "os"
+
+func main() {
+	if C.value() != 42 {
+		println("value() =", C.value(), "wanted 42")
+		os.Exit(1)
+	}
+}
+`)
+	tg.setenv("PKG_CONFIG_PATH", tg.path("."))
+	tg.run("run", tg.path("foo.go"))
+}
+
+func TestListTemplateContextFunction(t *testing.T) {
+	t.Parallel()
+	for _, tt := range []struct {
+		v    string
+		want string
+	}{
+		{"GOARCH", runtime.GOARCH},
+		{"GOOS", runtime.GOOS},
+		{"GOROOT", filepath.Clean(runtime.GOROOT())},
+		{"GOPATH", os.Getenv("GOPATH")},
+		{"CgoEnabled", ""},
+		{"UseAllFiles", ""},
+		{"Compiler", ""},
+		{"BuildTags", ""},
+		{"ReleaseTags", ""},
+		{"InstallSuffix", ""},
+	} {
+		tt := tt
+		t.Run(tt.v, func(t *testing.T) {
+			tg := testgo(t)
+			tg.parallel()
+			defer tg.cleanup()
+			tmpl := "{{context." + tt.v + "}}"
+			tg.run("list", "-f", tmpl)
+			if tt.want == "" {
+				return
+			}
+			if got := strings.TrimSpace(tg.getStdout()); got != tt.want {
+				t.Errorf("go list -f %q: got %q; want %q", tmpl, got, tt.want)
+			}
+		})
+	}
+}
+
+// Test that you cannot use a local import in a package
+// accessed by a non-local import (found in a GOPATH/GOROOT).
+// See golang.org/issue/17475.
+func TestImportLocal(t *testing.T) {
+	tooSlow(t)
+
+	tg := testgo(t)
+	tg.parallel()
+	defer tg.cleanup()
+
+	tg.tempFile("src/dir/x/x.go", `package x
+		var X int
+	`)
+	tg.setenv("GOPATH", tg.path("."))
+	tg.run("build", "dir/x")
+
+	// Ordinary import should work.
+	tg.tempFile("src/dir/p0/p.go", `package p0
+		import "dir/x"
+		var _ = x.X
+	`)
+	tg.run("build", "dir/p0")
+
+	// Relative import should not.
+	tg.tempFile("src/dir/p1/p.go", `package p1
+		import "../x"
+		var _ = x.X
+	`)
+	tg.runFail("build", "dir/p1")
+	tg.grepStderr("local import.*in non-local package", "did not diagnose local import")
+
+	// ... even in a test.
+	tg.tempFile("src/dir/p2/p.go", `package p2
+	`)
+	tg.tempFile("src/dir/p2/p_test.go", `package p2
+		import "../x"
+		import "testing"
+		var _ = x.X
+		func TestFoo(t *testing.T) {}
+	`)
+	tg.run("build", "dir/p2")
+	tg.runFail("test", "dir/p2")
+	tg.grepStderr("local import.*in non-local package", "did not diagnose local import")
+
+	// ... even in an xtest.
+	tg.tempFile("src/dir/p2/p_test.go", `package p2_test
+		import "../x"
+		import "testing"
+		var _ = x.X
+		func TestFoo(t *testing.T) {}
+	`)
+	tg.run("build", "dir/p2")
+	tg.runFail("test", "dir/p2")
+	tg.grepStderr("local import.*in non-local package", "did not diagnose local import")
+
+	// Relative import starting with ./ should not work either.
+	tg.tempFile("src/dir/d.go", `package dir
+		import "./x"
+		var _ = x.X
+	`)
+	tg.runFail("build", "dir")
+	tg.grepStderr("local import.*in non-local package", "did not diagnose local import")
+
+	// ... even in a test.
+	tg.tempFile("src/dir/d.go", `package dir
+	`)
+	tg.tempFile("src/dir/d_test.go", `package dir
+		import "./x"
+		import "testing"
+		var _ = x.X
+		func TestFoo(t *testing.T) {}
+	`)
+	tg.run("build", "dir")
+	tg.runFail("test", "dir")
+	tg.grepStderr("local import.*in non-local package", "did not diagnose local import")
+
+	// ... even in an xtest.
+	tg.tempFile("src/dir/d_test.go", `package dir_test
+		import "./x"
+		import "testing"
+		var _ = x.X
+		func TestFoo(t *testing.T) {}
+	`)
+	tg.run("build", "dir")
+	tg.runFail("test", "dir")
+	tg.grepStderr("local import.*in non-local package", "did not diagnose local import")
+
+	// Relative import plain ".." should not work.
+	tg.tempFile("src/dir/x/y/y.go", `package dir
+		import ".."
+		var _ = x.X
+	`)
+	tg.runFail("build", "dir/x/y")
+	tg.grepStderr("local import.*in non-local package", "did not diagnose local import")
+
+	// ... even in a test.
+	tg.tempFile("src/dir/x/y/y.go", `package y
+	`)
+	tg.tempFile("src/dir/x/y/y_test.go", `package y
+		import ".."
+		import "testing"
+		var _ = x.X
+		func TestFoo(t *testing.T) {}
+	`)
+	tg.run("build", "dir/x/y")
+	tg.runFail("test", "dir/x/y")
+	tg.grepStderr("local import.*in non-local package", "did not diagnose local import")
+
+	// ... even in an x test.
+	tg.tempFile("src/dir/x/y/y_test.go", `package y_test
+		import ".."
+		import "testing"
+		var _ = x.X
+		func TestFoo(t *testing.T) {}
+	`)
+	tg.run("build", "dir/x/y")
+	tg.runFail("test", "dir/x/y")
+	tg.grepStderr("local import.*in non-local package", "did not diagnose local import")
+
+	// Relative import "." should not work.
+	tg.tempFile("src/dir/x/xx.go", `package x
+		import "."
+		var _ = x.X
+	`)
+	tg.runFail("build", "dir/x")
+	tg.grepStderr("cannot import current directory", "did not diagnose import current directory")
+
+	// ... even in a test.
+	tg.tempFile("src/dir/x/xx.go", `package x
+	`)
+	tg.tempFile("src/dir/x/xx_test.go", `package x
+		import "."
+		import "testing"
+		var _ = x.X
+		func TestFoo(t *testing.T) {}
+	`)
+	tg.run("build", "dir/x")
+	tg.runFail("test", "dir/x")
+	tg.grepStderr("cannot import current directory", "did not diagnose import current directory")
+
+	// ... even in an xtest.
+	tg.tempFile("src/dir/x/xx.go", `package x
+	`)
+	tg.tempFile("src/dir/x/xx_test.go", `package x_test
+		import "."
+		import "testing"
+		var _ = x.X
+		func TestFoo(t *testing.T) {}
+	`)
+	tg.run("build", "dir/x")
+	tg.runFail("test", "dir/x")
+	tg.grepStderr("cannot import current directory", "did not diagnose import current directory")
+}
+
+func TestGoInstallPkgdir(t *testing.T) {
+	skipIfGccgo(t, "gccgo has no standard packages")
+	tooSlow(t)
+
+	tg := testgo(t)
+	tg.parallel()
+	defer tg.cleanup()
+	tg.makeTempdir()
+	pkg := tg.path(".")
+	tg.run("install", "-pkgdir", pkg, "sync")
+	tg.mustExist(filepath.Join(pkg, "sync.a"))
+	tg.mustNotExist(filepath.Join(pkg, "sync/atomic.a"))
+	tg.run("install", "-i", "-pkgdir", pkg, "sync")
+	tg.mustExist(filepath.Join(pkg, "sync.a"))
+	tg.mustExist(filepath.Join(pkg, "sync/atomic.a"))
+}
+
+// For issue 14337.
+func TestParallelTest(t *testing.T) {
+	tooSlow(t)
+	tg := testgo(t)
+	tg.parallel()
+	defer tg.cleanup()
+	tg.makeTempdir()
+	const testSrc = `package package_test
+		import (
+			"testing"
+		)
+		func TestTest(t *testing.T) {
+		}`
+	tg.tempFile("src/p1/p1_test.go", strings.Replace(testSrc, "package_test", "p1_test", 1))
+	tg.tempFile("src/p2/p2_test.go", strings.Replace(testSrc, "package_test", "p2_test", 1))
+	tg.tempFile("src/p3/p3_test.go", strings.Replace(testSrc, "package_test", "p3_test", 1))
+	tg.tempFile("src/p4/p4_test.go", strings.Replace(testSrc, "package_test", "p4_test", 1))
+	tg.setenv("GOPATH", tg.path("."))
+	tg.run("test", "-p=4", "p1", "p2", "p3", "p4")
+}
+
+func TestBinaryOnlyPackages(t *testing.T) {
+	tooSlow(t)
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOPATH", tg.path("."))
+
+	tg.tempFile("src/p1/p1.go", `//go:binary-only-package
+
+		package p1
+	`)
+	tg.wantStale("p1", "binary-only packages are no longer supported", "p1 is binary-only, and this message should always be printed")
+	tg.runFail("install", "p1")
+	tg.grepStderr("binary-only packages are no longer supported", "did not report attempt to compile binary-only package")
+
+	tg.tempFile("src/p1/p1.go", `
+		package p1
+		import "fmt"
+		func F(b bool) { fmt.Printf("hello from p1\n"); if b { F(false) } }
+	`)
+	tg.run("install", "p1")
+	os.Remove(tg.path("src/p1/p1.go"))
+	tg.mustNotExist(tg.path("src/p1/p1.go"))
+
+	tg.tempFile("src/p2/p2.go", `//go:binary-only-packages-are-not-great
+
+		package p2
+		import "p1"
+		func F() { p1.F(true) }
+	`)
+	tg.runFail("install", "p2")
+	tg.grepStderr("no Go files", "did not complain about missing sources")
+
+	tg.tempFile("src/p1/missing.go", `//go:binary-only-package
+
+		package p1
+		import _ "fmt"
+		func G()
+	`)
+	tg.wantStale("p1", "binary-only package", "should NOT want to rebuild p1 (first)")
+	tg.runFail("install", "p2")
+	tg.grepStderr("p1: binary-only packages are no longer supported", "did not report error for binary-only p1")
+
+	tg.run("list", "-deps", "-f", "{{.ImportPath}}: {{.BinaryOnly}}", "p2")
+	tg.grepStdout("p1: true", "p1 not listed as BinaryOnly")
+	tg.grepStdout("p2: false", "p2 listed as BinaryOnly")
+}
+
+// Issue 16050.
+func TestAlwaysLinkSysoFiles(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempDir("src/syso")
+	tg.tempFile("src/syso/a.syso", ``)
+	tg.tempFile("src/syso/b.go", `package syso`)
+	tg.setenv("GOPATH", tg.path("."))
+
+	// We should see the .syso file regardless of the setting of
+	// CGO_ENABLED.
+
+	tg.setenv("CGO_ENABLED", "1")
+	tg.run("list", "-f", "{{.SysoFiles}}", "syso")
+	tg.grepStdout("a.syso", "missing syso file with CGO_ENABLED=1")
+
+	tg.setenv("CGO_ENABLED", "0")
+	tg.run("list", "-f", "{{.SysoFiles}}", "syso")
+	tg.grepStdout("a.syso", "missing syso file with CGO_ENABLED=0")
+}
+
+// Issue 16120.
+func TestGenerateUsesBuildContext(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("this test won't run under Windows")
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempDir("src/gen")
+	tg.tempFile("src/gen/gen.go", "package gen\n//go:generate echo $GOOS $GOARCH\n")
+	tg.setenv("GOPATH", tg.path("."))
+
+	tg.setenv("GOOS", "linux")
+	tg.setenv("GOARCH", "amd64")
+	tg.run("generate", "gen")
+	tg.grepStdout("linux amd64", "unexpected GOOS/GOARCH combination")
+
+	tg.setenv("GOOS", "darwin")
+	tg.setenv("GOARCH", "arm64")
+	tg.run("generate", "gen")
+	tg.grepStdout("darwin arm64", "unexpected GOOS/GOARCH combination")
+}
+
+func TestGoEnv(t *testing.T) {
+	tg := testgo(t)
+	tg.parallel()
+	defer tg.cleanup()
+	tg.setenv("GOOS", "freebsd") // to avoid invalid pair errors
+	tg.setenv("GOARCH", "arm")
+	tg.run("env", "GOARCH")
+	tg.grepStdout("^arm$", "GOARCH not honored")
+
+	tg.run("env", "GCCGO")
+	tg.grepStdout(".", "GCCGO unexpectedly empty")
+
+	tg.run("env", "CGO_CFLAGS")
+	tg.grepStdout(".", "default CGO_CFLAGS unexpectedly empty")
+
+	tg.setenv("CGO_CFLAGS", "-foobar")
+	tg.run("env", "CGO_CFLAGS")
+	tg.grepStdout("^-foobar$", "CGO_CFLAGS not honored")
+
+	tg.setenv("CC", "gcc -fmust -fgo -ffaster")
+	tg.run("env", "CC")
+	tg.grepStdout("gcc", "CC not found")
+	tg.run("env", "GOGCCFLAGS")
+	tg.grepStdout("-ffaster", "CC arguments not found")
+
+	tg.run("env", "GOVERSION")
+	envVersion := strings.TrimSpace(tg.stdout.String())
+
+	tg.run("version")
+	cmdVersion := strings.TrimSpace(tg.stdout.String())
+
+	// If 'go version' is "go version <version> <goos>/<goarch>", then
+	// 'go env GOVERSION' is just "<version>".
+	if cmdVersion == envVersion || !strings.Contains(cmdVersion, envVersion) {
+		t.Fatalf("'go env GOVERSION' %q should be a shorter substring of 'go version' %q", envVersion, cmdVersion)
+	}
+}
+
+const (
+	noMatchesPattern = `(?m)^ok.*\[no tests to run\]`
+	okPattern        = `(?m)^ok`
+)
+
+// Issue 18044.
+func TestLdBindNow(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.setenv("LD_BIND_NOW", "1")
+	tg.run("help")
+}
+
+// Issue 18225.
+// This is really a cmd/asm issue but this is a convenient place to test it.
+func TestConcurrentAsm(t *testing.T) {
+	skipIfGccgo(t, "gccgo does not use cmd/asm")
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	asm := `DATA ·constants<>+0x0(SB)/8,$0
+GLOBL ·constants<>(SB),8,$8
+`
+	tg.tempFile("go/src/p/a.s", asm)
+	tg.tempFile("go/src/p/b.s", asm)
+	tg.tempFile("go/src/p/p.go", `package p`)
+	tg.setenv("GOPATH", tg.path("go"))
+	tg.run("build", "p")
+}
+
+// Issue 18975.
+func TestFFLAGS(t *testing.T) {
+	if !canCgo {
+		t.Skip("skipping because cgo not enabled")
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	tg.tempFile("p/src/p/main.go", `package main
+		// #cgo FFLAGS: -no-such-fortran-flag
+		import "C"
+		func main() {}
+	`)
+	tg.tempFile("p/src/p/a.f", `! comment`)
+	tg.setenv("GOPATH", tg.path("p"))
+
+	// This should normally fail because we are passing an unknown flag,
+	// but issue #19080 points to Fortran compilers that succeed anyhow.
+	// To work either way we call doRun directly rather than run or runFail.
+	tg.doRun([]string{"build", "-x", "p"})
+
+	tg.grepStderr("no-such-fortran-flag", `missing expected "-no-such-fortran-flag"`)
+}
+
+// Issue 19198.
+// This is really a cmd/link issue but this is a convenient place to test it.
+func TestDuplicateGlobalAsmSymbols(t *testing.T) {
+	skipIfGccgo(t, "gccgo does not use cmd/asm")
+	tooSlow(t)
+	if runtime.GOARCH != "386" && runtime.GOARCH != "amd64" {
+		t.Skipf("skipping test on %s", runtime.GOARCH)
+	}
+	if !canCgo {
+		t.Skip("skipping because cgo not enabled")
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	asm := `
+#include "textflag.h"
+
+DATA sym<>+0x0(SB)/8,$0
+GLOBL sym<>(SB),(NOPTR+RODATA),$8
+
+TEXT ·Data(SB),NOSPLIT,$0
+	MOVB sym<>(SB), AX
+	MOVB AX, ret+0(FP)
+	RET
+`
+	tg.tempFile("go/src/a/a.s", asm)
+	tg.tempFile("go/src/a/a.go", `package a; func Data() uint8`)
+	tg.tempFile("go/src/b/b.s", asm)
+	tg.tempFile("go/src/b/b.go", `package b; func Data() uint8`)
+	tg.tempFile("go/src/p/p.go", `
+package main
+import "a"
+import "b"
+import "C"
+func main() {
+	_ = a.Data() + b.Data()
+}
+`)
+	tg.setenv("GOPATH", tg.path("go"))
+	exe := tg.path("p.exe")
+	tg.creatingTemp(exe)
+	tg.run("build", "-o", exe, "p")
+}
+
+func copyFile(src, dst string, perm fs.FileMode) error {
+	sf, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer sf.Close()
+
+	df, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm)
+	if err != nil {
+		return err
+	}
+
+	_, err = io.Copy(df, sf)
+	err2 := df.Close()
+	if err != nil {
+		return err
+	}
+	return err2
+}
+
+func TestNeedVersion(t *testing.T) {
+	skipIfGccgo(t, "gccgo does not use cmd/compile")
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("goversion.go", `package main; func main() {}`)
+	path := tg.path("goversion.go")
+	tg.setenv("TESTGO_VERSION", "go1.testgo")
+	tg.runFail("run", path)
+	tg.grepStderr("compile", "does not match go tool version")
+}
+
+func TestBuildmodePIE(t *testing.T) {
+	if testing.Short() && testenv.Builder() == "" {
+		t.Skipf("skipping in -short mode on non-builder")
+	}
+
+	platform := fmt.Sprintf("%s/%s", runtime.GOOS, runtime.GOARCH)
+	switch platform {
+	case "linux/386", "linux/amd64", "linux/arm", "linux/arm64", "linux/ppc64le", "linux/riscv64", "linux/s390x",
+		"android/amd64", "android/arm", "android/arm64", "android/386",
+		"freebsd/amd64",
+		"windows/386", "windows/amd64", "windows/arm":
+	case "darwin/amd64":
+	default:
+		t.Skipf("skipping test because buildmode=pie is not supported on %s", platform)
+	}
+	t.Run("non-cgo", func(t *testing.T) {
+		testBuildmodePIE(t, false, true)
+	})
+	if canCgo {
+		switch runtime.GOOS {
+		case "darwin", "freebsd", "linux", "windows":
+			t.Run("cgo", func(t *testing.T) {
+				testBuildmodePIE(t, true, true)
+			})
+		}
+	}
+}
+
+func TestWindowsDefaultBuildmodIsPIE(t *testing.T) {
+	if testing.Short() && testenv.Builder() == "" {
+		t.Skipf("skipping in -short mode on non-builder")
+	}
+
+	if runtime.GOOS != "windows" {
+		t.Skip("skipping windows only test")
+	}
+
+	t.Run("non-cgo", func(t *testing.T) {
+		testBuildmodePIE(t, false, false)
+	})
+	if canCgo {
+		t.Run("cgo", func(t *testing.T) {
+			testBuildmodePIE(t, true, false)
+		})
+	}
+}
+
+func testBuildmodePIE(t *testing.T, useCgo, setBuildmodeToPIE bool) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	var s string
+	if useCgo {
+		s = `import "C";`
+	}
+	tg.tempFile("main.go", fmt.Sprintf(`package main;%s func main() { print("hello") }`, s))
+	src := tg.path("main.go")
+	obj := tg.path("main.exe")
+	args := []string{"build"}
+	if setBuildmodeToPIE {
+		args = append(args, "-buildmode=pie")
+	}
+	args = append(args, "-o", obj, src)
+	tg.run(args...)
+
+	switch runtime.GOOS {
+	case "linux", "android", "freebsd":
+		f, err := elf.Open(obj)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer f.Close()
+		if f.Type != elf.ET_DYN {
+			t.Errorf("PIE type must be ET_DYN, but %s", f.Type)
+		}
+	case "darwin":
+		f, err := macho.Open(obj)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer f.Close()
+		if f.Flags&macho.FlagDyldLink == 0 {
+			t.Error("PIE must have DyldLink flag, but not")
+		}
+		if f.Flags&macho.FlagPIE == 0 {
+			t.Error("PIE must have PIE flag, but not")
+		}
+	case "windows":
+		f, err := pe.Open(obj)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer f.Close()
+		if f.Section(".reloc") == nil {
+			t.Error(".reloc section is not present")
+		}
+		if (f.FileHeader.Characteristics & pe.IMAGE_FILE_RELOCS_STRIPPED) != 0 {
+			t.Error("IMAGE_FILE_RELOCS_STRIPPED flag is set")
+		}
+		var dc uint16
+		switch oh := f.OptionalHeader.(type) {
+		case *pe.OptionalHeader32:
+			dc = oh.DllCharacteristics
+		case *pe.OptionalHeader64:
+			dc = oh.DllCharacteristics
+			if (dc & pe.IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA) == 0 {
+				t.Error("IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA flag is not set")
+			}
+		default:
+			t.Fatalf("unexpected optional header type of %T", f.OptionalHeader)
+		}
+		if (dc & pe.IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE) == 0 {
+			t.Error("IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE flag is not set")
+		}
+		if useCgo {
+			// Test that only one symbol is exported (#40795).
+			// PIE binaries don´t require .edata section but unfortunately
+			// binutils doesn´t generate a .reloc section unless there is
+			// at least one symbol exported.
+			// See https://sourceware.org/bugzilla/show_bug.cgi?id=19011
+			section := f.Section(".edata")
+			if section == nil {
+				t.Skip(".edata section is not present")
+			}
+			// TODO: deduplicate this struct from cmd/link/internal/ld/pe.go
+			type IMAGE_EXPORT_DIRECTORY struct {
+				_                 [2]uint32
+				_                 [2]uint16
+				_                 [2]uint32
+				NumberOfFunctions uint32
+				NumberOfNames     uint32
+				_                 [3]uint32
+			}
+			var e IMAGE_EXPORT_DIRECTORY
+			if err := binary.Read(section.Open(), binary.LittleEndian, &e); err != nil {
+				t.Fatalf("binary.Read failed: %v", err)
+			}
+
+			// Only _cgo_dummy_export should be exported
+			if e.NumberOfFunctions != 1 {
+				t.Fatalf("got %d exported functions; want 1", e.NumberOfFunctions)
+			}
+			if e.NumberOfNames != 1 {
+				t.Fatalf("got %d exported names; want 1", e.NumberOfNames)
+			}
+		}
+	default:
+		panic("unreachable")
+	}
+
+	out, err := exec.Command(obj).CombinedOutput()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if string(out) != "hello" {
+		t.Errorf("got %q; want %q", out, "hello")
+	}
+}
+
+func TestUpxCompression(t *testing.T) {
+	if runtime.GOOS != "linux" ||
+		(runtime.GOARCH != "amd64" && runtime.GOARCH != "386") {
+		t.Skipf("skipping upx test on %s/%s", runtime.GOOS, runtime.GOARCH)
+	}
+
+	testenv.MustHaveExecPath(t, "upx")
+	out, err := exec.Command("upx", "--version").CombinedOutput()
+	if err != nil {
+		t.Fatalf("upx --version failed: %v", err)
+	}
+
+	// upx --version prints `upx <version>` in the first line of output:
+	//   upx 3.94
+	//   [...]
+	re := regexp.MustCompile(`([[:digit:]]+)\.([[:digit:]]+)`)
+	upxVersion := re.FindStringSubmatch(string(out))
+	if len(upxVersion) != 3 {
+		t.Fatalf("bad upx version string: %s", upxVersion)
+	}
+
+	major, err1 := strconv.Atoi(upxVersion[1])
+	minor, err2 := strconv.Atoi(upxVersion[2])
+	if err1 != nil || err2 != nil {
+		t.Fatalf("bad upx version string: %s", upxVersion[0])
+	}
+
+	// Anything below 3.94 is known not to work with go binaries
+	if (major < 3) || (major == 3 && minor < 94) {
+		t.Skipf("skipping because upx version %v.%v is too old", major, minor)
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	tg.tempFile("main.go", `package main; import "fmt"; func main() { fmt.Print("hello upx") }`)
+	src := tg.path("main.go")
+	obj := tg.path("main")
+	tg.run("build", "-o", obj, src)
+
+	out, err = exec.Command("upx", obj).CombinedOutput()
+	if err != nil {
+		t.Logf("executing upx\n%s\n", out)
+		t.Fatalf("upx failed with %v", err)
+	}
+
+	out, err = exec.Command(obj).CombinedOutput()
+	if err != nil {
+		t.Logf("%s", out)
+		t.Fatalf("running compressed go binary failed with error %s", err)
+	}
+	if string(out) != "hello upx" {
+		t.Fatalf("bad output from compressed go binary:\ngot %q; want %q", out, "hello upx")
+	}
+}
+
+func TestCacheListStale(t *testing.T) {
+	tooSlow(t)
+	if godebug.Get("gocacheverify") == "1" {
+		t.Skip("GODEBUG gocacheverify")
+	}
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOCACHE", tg.path("cache"))
+	tg.tempFile("gopath/src/p/p.go", "package p; import _ \"q\"; func F(){}\n")
+	tg.tempFile("gopath/src/q/q.go", "package q; func F(){}\n")
+	tg.tempFile("gopath/src/m/m.go", "package main; import _ \"q\"; func main(){}\n")
+
+	tg.setenv("GOPATH", tg.path("gopath"))
+	tg.run("install", "p", "m")
+	tg.run("list", "-f={{.ImportPath}} {{.Stale}}", "m", "q", "p")
+	tg.grepStdout("^m false", "m should not be stale")
+	tg.grepStdout("^q true", "q should be stale")
+	tg.grepStdout("^p false", "p should not be stale")
+}
+
+func TestCacheCoverage(t *testing.T) {
+	tooSlow(t)
+
+	if godebug.Get("gocacheverify") == "1" {
+		t.Skip("GODEBUG gocacheverify")
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
+	tg.makeTempdir()
+
+	tg.setenv("GOCACHE", tg.path("c1"))
+	tg.run("test", "-cover", "-short", "strings")
+	tg.run("test", "-cover", "-short", "math", "strings")
+}
+
+func TestIssue22588(t *testing.T) {
+	// Don't get confused by stderr coming from tools.
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	if _, err := os.Stat("/usr/bin/time"); err != nil {
+		t.Skip(err)
+	}
+
+	tg.run("list", "-f={{.Stale}}", "runtime")
+	tg.run("list", "-toolexec=/usr/bin/time", "-f={{.Stale}}", "runtime")
+	tg.grepStdout("false", "incorrectly reported runtime as stale")
+}
+
+func TestIssue22531(t *testing.T) {
+	tooSlow(t)
+	if godebug.Get("gocacheverify") == "1" {
+		t.Skip("GODEBUG gocacheverify")
+	}
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOPATH", tg.tempdir)
+	tg.setenv("GOCACHE", tg.path("cache"))
+	tg.tempFile("src/m/main.go", "package main /* c1 */; func main() {}\n")
+	tg.run("install", "-x", "m")
+	tg.run("list", "-f", "{{.Stale}}", "m")
+	tg.grepStdout("false", "reported m as stale after install")
+	tg.run("tool", "buildid", tg.path("bin/m"+exeSuffix))
+
+	// The link action ID did not include the full main build ID,
+	// even though the full main build ID is written into the
+	// eventual binary. That caused the following install to
+	// be a no-op, thinking the gofmt binary was up-to-date,
+	// even though .Stale could see it was not.
+	tg.tempFile("src/m/main.go", "package main /* c2 */; func main() {}\n")
+	tg.run("install", "-x", "m")
+	tg.run("list", "-f", "{{.Stale}}", "m")
+	tg.grepStdout("false", "reported m as stale after reinstall")
+	tg.run("tool", "buildid", tg.path("bin/m"+exeSuffix))
+}
+
+func TestIssue22596(t *testing.T) {
+	tooSlow(t)
+	if godebug.Get("gocacheverify") == "1" {
+		t.Skip("GODEBUG gocacheverify")
+	}
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOCACHE", tg.path("cache"))
+	tg.tempFile("gopath1/src/p/p.go", "package p; func F(){}\n")
+	tg.tempFile("gopath2/src/p/p.go", "package p; func F(){}\n")
+
+	tg.setenv("GOPATH", tg.path("gopath1"))
+	tg.run("list", "-f={{.Target}}", "p")
+	target1 := strings.TrimSpace(tg.getStdout())
+	tg.run("install", "p")
+	tg.wantNotStale("p", "", "p stale after install")
+
+	tg.setenv("GOPATH", tg.path("gopath2"))
+	tg.run("list", "-f={{.Target}}", "p")
+	target2 := strings.TrimSpace(tg.getStdout())
+	tg.must(os.MkdirAll(filepath.Dir(target2), 0777))
+	tg.must(copyFile(target1, target2, 0666))
+	tg.wantStale("p", "build ID mismatch", "p not stale after copy from gopath1")
+	tg.run("install", "p")
+	tg.wantNotStale("p", "", "p stale after install2")
+}
+
+func TestTestCache(t *testing.T) {
+	tooSlow(t)
+
+	if godebug.Get("gocacheverify") == "1" {
+		t.Skip("GODEBUG gocacheverify")
+	}
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOPATH", tg.tempdir)
+	tg.setenv("GOCACHE", tg.path("cache"))
+
+	// The -p=1 in the commands below just makes the -x output easier to read.
+
+	t.Log("\n\nINITIAL\n\n")
+
+	tg.tempFile("src/p1/p1.go", "package p1\nvar X =  1\n")
+	tg.tempFile("src/p2/p2.go", "package p2\nimport _ \"p1\"\nvar X = 1\n")
+	tg.tempFile("src/t/t1/t1_test.go", "package t\nimport \"testing\"\nfunc Test1(*testing.T) {}\n")
+	tg.tempFile("src/t/t2/t2_test.go", "package t\nimport _ \"p1\"\nimport \"testing\"\nfunc Test2(*testing.T) {}\n")
+	tg.tempFile("src/t/t3/t3_test.go", "package t\nimport \"p1\"\nimport \"testing\"\nfunc Test3(t *testing.T) {t.Log(p1.X)}\n")
+	tg.tempFile("src/t/t4/t4_test.go", "package t\nimport \"p2\"\nimport \"testing\"\nfunc Test4(t *testing.T) {t.Log(p2.X)}")
+	tg.run("test", "-x", "-v", "-short", "t/...")
+
+	t.Log("\n\nREPEAT\n\n")
+
+	tg.run("test", "-x", "-v", "-short", "t/...")
+	tg.grepStdout(`ok  \tt/t1\t\(cached\)`, "did not cache t1")
+	tg.grepStdout(`ok  \tt/t2\t\(cached\)`, "did not cache t2")
+	tg.grepStdout(`ok  \tt/t3\t\(cached\)`, "did not cache t3")
+	tg.grepStdout(`ok  \tt/t4\t\(cached\)`, "did not cache t4")
+	tg.grepStderrNot(`[\\/](compile|gccgo) `, "incorrectly ran compiler")
+	tg.grepStderrNot(`[\\/](link|gccgo) `, "incorrectly ran linker")
+	tg.grepStderrNot(`p[0-9]\.test`, "incorrectly ran test")
+
+	t.Log("\n\nCOMMENT\n\n")
+
+	// Changing the program text without affecting the compiled package
+	// should result in the package being rebuilt but nothing more.
+	tg.tempFile("src/p1/p1.go", "package p1\nvar X = 01\n")
+	tg.run("test", "-p=1", "-x", "-v", "-short", "t/...")
+	tg.grepStdout(`ok  \tt/t1\t\(cached\)`, "did not cache t1")
+	tg.grepStdout(`ok  \tt/t2\t\(cached\)`, "did not cache t2")
+	tg.grepStdout(`ok  \tt/t3\t\(cached\)`, "did not cache t3")
+	tg.grepStdout(`ok  \tt/t4\t\(cached\)`, "did not cache t4")
+	tg.grepStderrNot(`([\\/](compile|gccgo) ).*t[0-9]_test\.go`, "incorrectly ran compiler")
+	tg.grepStderrNot(`[\\/](link|gccgo) `, "incorrectly ran linker")
+	tg.grepStderrNot(`t[0-9]\.test.*test\.short`, "incorrectly ran test")
+
+	t.Log("\n\nCHANGE\n\n")
+
+	// Changing the actual package should have limited effects.
+	tg.tempFile("src/p1/p1.go", "package p1\nvar X = 02\n")
+	tg.run("test", "-p=1", "-x", "-v", "-short", "t/...")
+
+	// p2 should have been rebuilt.
+	tg.grepStderr(`([\\/]compile|gccgo).*p2.go`, "did not recompile p2")
+
+	// t1 does not import anything, should not have been rebuilt.
+	tg.grepStderrNot(`([\\/]compile|gccgo).*t1_test.go`, "incorrectly recompiled t1")
+	tg.grepStderrNot(`([\\/]link|gccgo).*t1_test`, "incorrectly relinked t1_test")
+	tg.grepStdout(`ok  \tt/t1\t\(cached\)`, "did not cache t/t1")
+
+	// t2 imports p1 and must be rebuilt and relinked,
+	// but the change should not have any effect on the test binary,
+	// so the test should not have been rerun.
+	tg.grepStderr(`([\\/]compile|gccgo).*t2_test.go`, "did not recompile t2")
+	tg.grepStderr(`([\\/]link|gccgo).*t2\.test`, "did not relink t2_test")
+	// This check does not currently work with gccgo, as garbage
+	// collection of unused variables is not turned on by default.
+	if runtime.Compiler != "gccgo" {
+		tg.grepStdout(`ok  \tt/t2\t\(cached\)`, "did not cache t/t2")
+	}
+
+	// t3 imports p1, and changing X changes t3's test binary.
+	tg.grepStderr(`([\\/]compile|gccgo).*t3_test.go`, "did not recompile t3")
+	tg.grepStderr(`([\\/]link|gccgo).*t3\.test`, "did not relink t3_test")
+	tg.grepStderr(`t3\.test.*-test.short`, "did not rerun t3_test")
+	tg.grepStdoutNot(`ok  \tt/t3\t\(cached\)`, "reported cached t3_test result")
+
+	// t4 imports p2, but p2 did not change, so t4 should be relinked, not recompiled,
+	// and not rerun.
+	tg.grepStderrNot(`([\\/]compile|gccgo).*t4_test.go`, "incorrectly recompiled t4")
+	tg.grepStderr(`([\\/]link|gccgo).*t4\.test`, "did not relink t4_test")
+	// This check does not currently work with gccgo, as garbage
+	// collection of unused variables is not turned on by default.
+	if runtime.Compiler != "gccgo" {
+		tg.grepStdout(`ok  \tt/t4\t\(cached\)`, "did not cache t/t4")
+	}
+}
+
+func TestTestSkipVetAfterFailedBuild(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	tg.tempFile("x_test.go", `package x
+		func f() {
+			return 1
+		}
+	`)
+
+	tg.runFail("test", tg.path("x_test.go"))
+	tg.grepStderrNot(`vet`, "vet should be skipped after the failed build")
+}
+
+func TestTestVetRebuild(t *testing.T) {
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	// golang.org/issue/23701.
+	// b_test imports b with augmented method from export_test.go.
+	// b_test also imports a, which imports b.
+	// Must not accidentally see un-augmented b propagate through a to b_test.
+	tg.tempFile("src/a/a.go", `package a
+		import "b"
+		type Type struct{}
+		func (*Type) M() b.T {return 0}
+	`)
+	tg.tempFile("src/b/b.go", `package b
+		type T int
+		type I interface {M() T}
+	`)
+	tg.tempFile("src/b/export_test.go", `package b
+		func (*T) Method() *T { return nil }
+	`)
+	tg.tempFile("src/b/b_test.go", `package b_test
+		import (
+			"testing"
+			"a"
+			. "b"
+		)
+		func TestBroken(t *testing.T) {
+			x := new(T)
+			x.Method()
+			_ = new(a.Type)
+		}
+	`)
+
+	tg.setenv("GOPATH", tg.path("."))
+	tg.run("test", "b")
+	tg.run("vet", "b")
+}
+
+func TestInstallDeps(t *testing.T) {
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.makeTempdir()
+	tg.setenv("GOPATH", tg.tempdir)
+
+	tg.tempFile("src/p1/p1.go", "package p1\nvar X =  1\n")
+	tg.tempFile("src/p2/p2.go", "package p2\nimport _ \"p1\"\n")
+	tg.tempFile("src/main1/main.go", "package main\nimport _ \"p2\"\nfunc main() {}\n")
+
+	tg.run("list", "-f={{.Target}}", "p1")
+	p1 := strings.TrimSpace(tg.getStdout())
+	tg.run("list", "-f={{.Target}}", "p2")
+	p2 := strings.TrimSpace(tg.getStdout())
+	tg.run("list", "-f={{.Target}}", "main1")
+	main1 := strings.TrimSpace(tg.getStdout())
+
+	tg.run("install", "main1")
+
+	tg.mustExist(main1)
+	tg.mustNotExist(p2)
+	tg.mustNotExist(p1)
+
+	tg.run("install", "p2")
+	tg.mustExist(p2)
+	tg.mustNotExist(p1)
+
+	// don't let install -i overwrite runtime
+	tg.wantNotStale("runtime", "", "must be non-stale before install -i")
+
+	tg.run("install", "-i", "main1")
+	tg.mustExist(p1)
+	tg.must(os.Remove(p1))
+
+	tg.run("install", "-i", "p2")
+	tg.mustExist(p1)
+}
+
+// Issue 22986.
+func TestImportPath(t *testing.T) {
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	tg.tempFile("src/a/a.go", `
+package main
+
+import (
+	"log"
+	p "a/p-1.0"
+)
+
+func main() {
+	if !p.V {
+		log.Fatal("false")
+	}
+}`)
+
+	tg.tempFile("src/a/a_test.go", `
+package main_test
+
+import (
+	p "a/p-1.0"
+	"testing"
+)
+
+func TestV(t *testing.T) {
+	if !p.V {
+		t.Fatal("false")
+	}
+}`)
+
+	tg.tempFile("src/a/p-1.0/p.go", `
+package p
+
+var V = true
+
+func init() {}
+`)
+
+	tg.setenv("GOPATH", tg.path("."))
+	tg.run("build", "-o", tg.path("a.exe"), "a")
+	tg.run("test", "a")
+}
+
+func TestBadCommandLines(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+
+	tg.tempFile("src/x/x.go", "package x\n")
+	tg.setenv("GOPATH", tg.path("."))
+
+	tg.run("build", "x")
+
+	tg.tempFile("src/x/@y.go", "package x\n")
+	tg.runFail("build", "x")
+	tg.grepStderr("invalid input file name \"@y.go\"", "did not reject @y.go")
+	tg.must(os.Remove(tg.path("src/x/@y.go")))
+
+	tg.tempFile("src/x/-y.go", "package x\n")
+	tg.runFail("build", "x")
+	tg.grepStderr("invalid input file name \"-y.go\"", "did not reject -y.go")
+	tg.must(os.Remove(tg.path("src/x/-y.go")))
+
+	if runtime.Compiler == "gccgo" {
+		tg.runFail("build", "-gccgoflags=all=@x", "x")
+	} else {
+		tg.runFail("build", "-gcflags=all=@x", "x")
+	}
+	tg.grepStderr("invalid command-line argument @x in command", "did not reject @x during exec")
+
+	tg.tempFile("src/@x/x.go", "package x\n")
+	tg.setenv("GOPATH", tg.path("."))
+	tg.runFail("build", "@x")
+	tg.grepStderr("invalid input directory name \"@x\"|can only use path@version syntax with 'go get' and 'go install' in module-aware mode", "did not reject @x directory")
+
+	tg.tempFile("src/@x/y/y.go", "package y\n")
+	tg.setenv("GOPATH", tg.path("."))
+	tg.runFail("build", "@x/y")
+	tg.grepStderr("invalid import path \"@x/y\"|can only use path@version syntax with 'go get' and 'go install' in module-aware mode", "did not reject @x/y import path")
+
+	tg.tempFile("src/-x/x.go", "package x\n")
+	tg.setenv("GOPATH", tg.path("."))
+	tg.runFail("build", "--", "-x")
+	tg.grepStderr("invalid import path \"-x\"", "did not reject -x import path")
+
+	tg.tempFile("src/-x/y/y.go", "package y\n")
+	tg.setenv("GOPATH", tg.path("."))
+	tg.runFail("build", "--", "-x/y")
+	tg.grepStderr("invalid import path \"-x/y\"", "did not reject -x/y import path")
+}
+
+func TestTwoPkgConfigs(t *testing.T) {
+	if !canCgo {
+		t.Skip("no cgo")
+	}
+	if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
+		t.Skipf("no shell scripts on %s", runtime.GOOS)
+	}
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("src/x/a.go", `package x
+		// #cgo pkg-config: --static a
+		import "C"
+	`)
+	tg.tempFile("src/x/b.go", `package x
+		// #cgo pkg-config: --static a
+		import "C"
+	`)
+	tg.tempFile("pkg-config.sh", `#!/bin/sh
+echo $* >>`+tg.path("pkg-config.out"))
+	tg.must(os.Chmod(tg.path("pkg-config.sh"), 0755))
+	tg.setenv("GOPATH", tg.path("."))
+	tg.setenv("PKG_CONFIG", tg.path("pkg-config.sh"))
+	tg.run("build", "x")
+	out, err := os.ReadFile(tg.path("pkg-config.out"))
+	tg.must(err)
+	out = bytes.TrimSpace(out)
+	want := "--cflags --static --static -- a a\n--libs --static --static -- a a"
+	if !bytes.Equal(out, []byte(want)) {
+		t.Errorf("got %q want %q", out, want)
+	}
+}
+
+func TestCgoCache(t *testing.T) {
+	if !canCgo {
+		t.Skip("no cgo")
+	}
+	tooSlow(t)
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("src/x/a.go", `package main
+		// #ifndef VAL
+		// #define VAL 0
+		// #endif
+		// int val = VAL;
+		import "C"
+		import "fmt"
+		func main() { fmt.Println(C.val) }
+	`)
+	tg.setenv("GOPATH", tg.path("."))
+	exe := tg.path("x.exe")
+	tg.run("build", "-o", exe, "x")
+	tg.setenv("CGO_LDFLAGS", "-lnosuchlibraryexists")
+	tg.runFail("build", "-o", exe, "x")
+	tg.grepStderr(`nosuchlibraryexists`, "did not run linker with changed CGO_LDFLAGS")
+}
+
+// Issue 23982
+func TestFilepathUnderCwdFormat(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.run("test", "-x", "-cover", "log")
+	tg.grepStderrNot(`\.log\.cover\.go`, "-x output should contain correctly formatted filepath under cwd")
+}
+
+// Issue 24396.
+func TestDontReportRemoveOfEmptyDir(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("src/a/a.go", `package a`)
+	tg.setenv("GOPATH", tg.path("."))
+	tg.run("install", "-x", "a")
+	tg.run("install", "-x", "a")
+	// The second install should have printed only a WORK= line,
+	// nothing else.
+	if bytes.Count(tg.stdout.Bytes(), []byte{'\n'})+bytes.Count(tg.stderr.Bytes(), []byte{'\n'}) > 1 {
+		t.Error("unnecessary output when installing installed package")
+	}
+}
+
+// Issue 24704.
+func TestLinkerTmpDirIsDeleted(t *testing.T) {
+	skipIfGccgo(t, "gccgo does not use cmd/link")
+	if !canCgo {
+		t.Skip("skipping because cgo not enabled")
+	}
+	tooSlow(t)
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("a.go", `package main; import "C"; func main() {}`)
+	tg.run("build", "-ldflags", "-v", "-o", os.DevNull, tg.path("a.go"))
+	// Find line that has "host link:" in linker output.
+	stderr := tg.getStderr()
+	var hostLinkLine string
+	for _, line := range strings.Split(stderr, "\n") {
+		if !strings.Contains(line, "host link:") {
+			continue
+		}
+		hostLinkLine = line
+		break
+	}
+	if hostLinkLine == "" {
+		t.Fatal(`fail to find with "host link:" string in linker output`)
+	}
+	// Find parameter, like "/tmp/go-link-408556474/go.o" inside of
+	// "host link:" line, and extract temp directory /tmp/go-link-408556474
+	// out of it.
+	tmpdir := hostLinkLine
+	i := strings.Index(tmpdir, `go.o"`)
+	if i == -1 {
+		t.Fatalf(`fail to find "go.o" in "host link:" line %q`, hostLinkLine)
+	}
+	tmpdir = tmpdir[:i-1]
+	i = strings.LastIndex(tmpdir, `"`)
+	if i == -1 {
+		t.Fatalf(`fail to find " in "host link:" line %q`, hostLinkLine)
+	}
+	tmpdir = tmpdir[i+1:]
+	// Verify that temp directory has been removed.
+	_, err := os.Stat(tmpdir)
+	if err == nil {
+		t.Fatalf("temp directory %q has not been removed", tmpdir)
+	}
+	if !os.IsNotExist(err) {
+		t.Fatalf("Stat(%q) returns unexpected error: %v", tmpdir, err)
+	}
+}
+
+// Issue 25093.
+func TestCoverpkgTestOnly(t *testing.T) {
+	skipIfGccgo(t, "gccgo has no cover tool")
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("src/a/a.go", `package a
+		func F(i int) int {
+			return i*i
+		}`)
+	tg.tempFile("src/atest/a_test.go", `
+		package a_test
+		import ( "a"; "testing" )
+		func TestF(t *testing.T) { a.F(2) }
+	`)
+	tg.setenv("GOPATH", tg.path("."))
+	tg.run("test", "-coverpkg=a", "atest")
+	tg.grepStderrNot("no packages being tested depend on matches", "bad match message")
+	tg.grepStdout("coverage: 100", "no coverage")
+}
+
+// Regression test for golang.org/issue/34499: version command should not crash
+// when executed in a deleted directory on Linux.
+func TestExecInDeletedDir(t *testing.T) {
+	switch runtime.GOOS {
+	case "windows", "plan9",
+		"aix",                // Fails with "device busy".
+		"solaris", "illumos": // Fails with "invalid argument".
+		t.Skipf("%v does not support removing the current working directory", runtime.GOOS)
+	}
+	tg := testgo(t)
+	defer tg.cleanup()
+
+	wd, err := os.Getwd()
+	tg.check(err)
+	tg.makeTempdir()
+	tg.check(os.Chdir(tg.tempdir))
+	defer func() { tg.check(os.Chdir(wd)) }()
+
+	tg.check(os.Remove(tg.tempdir))
+
+	// `go version` should not fail
+	tg.run("version")
+}
+
+// A missing C compiler should not force the net package to be stale.
+// Issue 47215.
+func TestMissingCC(t *testing.T) {
+	if !canCgo {
+		t.Skip("test is only meaningful on systems with cgo")
+	}
+	cc := os.Getenv("CC")
+	if cc == "" {
+		cc = "gcc"
+	}
+	if filepath.IsAbs(cc) {
+		t.Skipf(`"CC" (%s) is an absolute path`, cc)
+	}
+	_, err := exec.LookPath(cc)
+	if err != nil {
+		t.Skipf(`"CC" (%s) not on PATH`, cc)
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	netStale, _ := tg.isStale("net")
+	if netStale {
+		t.Skip(`skipping test because "net" package is currently stale`)
+	}
+
+	tg.setenv("PATH", "") // No C compiler on PATH.
+	netStale, _ = tg.isStale("net")
+	if netStale {
+		t.Error(`clearing "PATH" causes "net" to be stale`)
+	}
+}