Adding upstream version 1.22.1.upstream/1.22.1

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

10 files changed, 2969 insertions, 0 deletions

diff --git a/src/cmd/go/internal/test/cover.go b/src/cmd/go/internal/test/cover.go
new file mode 100644
index 0000000..f614458
--- /dev/null
+++ b/src/cmd/go/internal/test/cover.go
@@ -0,0 +1,85 @@
+// Copyright 2017 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 test
+
+import (
+	"cmd/go/internal/base"
+	"cmd/go/internal/cfg"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sync"
+)
+
+var coverMerge struct {
+	f          *os.File
+	sync.Mutex // for f.Write
+}
+
+// initCoverProfile initializes the test coverage profile.
+// It must be run before any calls to mergeCoverProfile or closeCoverProfile.
+// Using this function clears the profile in case it existed from a previous run,
+// or in case it doesn't exist and the test is going to fail to create it (or not run).
+func initCoverProfile() {
+	if testCoverProfile == "" || testC {
+		return
+	}
+	if !filepath.IsAbs(testCoverProfile) {
+		testCoverProfile = filepath.Join(testOutputDir.getAbs(), testCoverProfile)
+	}
+
+	// No mutex - caller's responsibility to call with no racing goroutines.
+	f, err := os.Create(testCoverProfile)
+	if err != nil {
+		base.Fatalf("%v", err)
+	}
+	_, err = fmt.Fprintf(f, "mode: %s\n", cfg.BuildCoverMode)
+	if err != nil {
+		base.Fatalf("%v", err)
+	}
+	coverMerge.f = f
+}
+
+// mergeCoverProfile merges file into the profile stored in testCoverProfile.
+// It prints any errors it encounters to ew.
+func mergeCoverProfile(ew io.Writer, file string) {
+	if coverMerge.f == nil {
+		return
+	}
+	coverMerge.Lock()
+	defer coverMerge.Unlock()
+
+	expect := fmt.Sprintf("mode: %s\n", cfg.BuildCoverMode)
+	buf := make([]byte, len(expect))
+	r, err := os.Open(file)
+	if err != nil {
+		// Test did not create profile, which is OK.
+		return
+	}
+	defer r.Close()
+
+	n, err := io.ReadFull(r, buf)
+	if n == 0 {
+		return
+	}
+	if err != nil || string(buf) != expect {
+		fmt.Fprintf(ew, "error: test wrote malformed coverage profile %s.\n", file)
+		return
+	}
+	_, err = io.Copy(coverMerge.f, r)
+	if err != nil {
+		fmt.Fprintf(ew, "error: saving coverage profile: %v\n", err)
+	}
+}
+
+func closeCoverProfile() {
+	if coverMerge.f == nil {
+		return
+	}
+	if err := coverMerge.f.Close(); err != nil {
+		base.Errorf("closing coverage profile: %v", err)
+	}
+}
diff --git a/src/cmd/go/internal/test/flagdefs.go b/src/cmd/go/internal/test/flagdefs.go
new file mode 100644
index 0000000..baa0cdf
--- /dev/null
+++ b/src/cmd/go/internal/test/flagdefs.go
@@ -0,0 +1,79 @@
+// Copyright 2019 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.
+
+// Code generated by genflags.go — DO NOT EDIT.
+
+package test
+
+// passFlagToTest contains the flags that should be forwarded to
+// the test binary with the prefix "test.".
+var passFlagToTest = map[string]bool{
+	"bench":                true,
+	"benchmem":             true,
+	"benchtime":            true,
+	"blockprofile":         true,
+	"blockprofilerate":     true,
+	"count":                true,
+	"coverprofile":         true,
+	"cpu":                  true,
+	"cpuprofile":           true,
+	"failfast":             true,
+	"fullpath":             true,
+	"fuzz":                 true,
+	"fuzzminimizetime":     true,
+	"fuzztime":             true,
+	"list":                 true,
+	"memprofile":           true,
+	"memprofilerate":       true,
+	"mutexprofile":         true,
+	"mutexprofilefraction": true,
+	"outputdir":            true,
+	"parallel":             true,
+	"run":                  true,
+	"short":                true,
+	"shuffle":              true,
+	"skip":                 true,
+	"timeout":              true,
+	"trace":                true,
+	"v":                    true,
+}
+
+var passAnalyzersToVet = map[string]bool{
+	"appends":          true,
+	"asmdecl":          true,
+	"assign":           true,
+	"atomic":           true,
+	"bool":             true,
+	"bools":            true,
+	"buildtag":         true,
+	"buildtags":        true,
+	"cgocall":          true,
+	"composites":       true,
+	"copylocks":        true,
+	"defers":           true,
+	"directive":        true,
+	"errorsas":         true,
+	"framepointer":     true,
+	"httpresponse":     true,
+	"ifaceassert":      true,
+	"loopclosure":      true,
+	"lostcancel":       true,
+	"methods":          true,
+	"nilfunc":          true,
+	"printf":           true,
+	"rangeloops":       true,
+	"shift":            true,
+	"sigchanyzer":      true,
+	"slog":             true,
+	"stdmethods":       true,
+	"stringintconv":    true,
+	"structtag":        true,
+	"testinggoroutine": true,
+	"tests":            true,
+	"timeformat":       true,
+	"unmarshal":        true,
+	"unreachable":      true,
+	"unsafeptr":        true,
+	"unusedresult":     true,
+}
diff --git a/src/cmd/go/internal/test/flagdefs_test.go b/src/cmd/go/internal/test/flagdefs_test.go
new file mode 100644
index 0000000..5461b2d
--- /dev/null
+++ b/src/cmd/go/internal/test/flagdefs_test.go
@@ -0,0 +1,76 @@
+// Copyright 2019 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 test
+
+import (
+	"cmd/go/internal/cfg"
+	"cmd/go/internal/test/internal/genflags"
+	"internal/testenv"
+	"maps"
+	"os"
+	"testing"
+)
+
+func TestMain(m *testing.M) {
+	cfg.SetGOROOT(testenv.GOROOT(nil), false)
+	os.Exit(m.Run())
+}
+
+func TestPassFlagToTest(t *testing.T) {
+	wantNames := genflags.ShortTestFlags()
+
+	missing := map[string]bool{}
+	for _, name := range wantNames {
+		if !passFlagToTest[name] {
+			missing[name] = true
+		}
+	}
+	if len(missing) > 0 {
+		t.Errorf("passFlagToTest is missing entries: %v", missing)
+	}
+
+	extra := maps.Clone(passFlagToTest)
+	for _, name := range wantNames {
+		delete(extra, name)
+	}
+	if len(extra) > 0 {
+		t.Errorf("passFlagToTest contains extra entries: %v", extra)
+	}
+
+	if t.Failed() {
+		t.Logf("To regenerate:\n\tgo generate cmd/go/internal/test")
+	}
+}
+
+func TestPassAnalyzersToVet(t *testing.T) {
+	testenv.MustHaveGoBuild(t) // runs 'go tool vet -flags'
+
+	wantNames, err := genflags.VetAnalyzers()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	missing := map[string]bool{}
+	for _, name := range wantNames {
+		if !passAnalyzersToVet[name] {
+			missing[name] = true
+		}
+	}
+	if len(missing) > 0 {
+		t.Errorf("passAnalyzersToVet is missing entries: %v", missing)
+	}
+
+	extra := maps.Clone(passAnalyzersToVet)
+	for _, name := range wantNames {
+		delete(extra, name)
+	}
+	if len(extra) > 0 {
+		t.Errorf("passFlagToTest contains extra entries: %v", extra)
+	}
+
+	if t.Failed() {
+		t.Logf("To regenerate:\n\tgo generate cmd/go/internal/test")
+	}
+}
diff --git a/src/cmd/go/internal/test/genflags.go b/src/cmd/go/internal/test/genflags.go
new file mode 100644
index 0000000..bb5ceb6
--- /dev/null
+++ b/src/cmd/go/internal/test/genflags.go
@@ -0,0 +1,84 @@
+// Copyright 2019 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.
+
+//go:build ignore
+
+package main
+
+import (
+	"bytes"
+	"log"
+	"os"
+	"os/exec"
+	"text/template"
+
+	"cmd/go/internal/test/internal/genflags"
+)
+
+func main() {
+	if err := regenerate(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func regenerate() error {
+	vetAnalyzers, err := genflags.VetAnalyzers()
+	if err != nil {
+		return err
+	}
+
+	t := template.Must(template.New("fileTemplate").Parse(fileTemplate))
+	tData := map[string][]string{
+		"testFlags":    genflags.ShortTestFlags(),
+		"vetAnalyzers": vetAnalyzers,
+	}
+	buf := bytes.NewBuffer(nil)
+	if err := t.Execute(buf, tData); err != nil {
+		return err
+	}
+
+	f, err := os.Create("flagdefs.go")
+	if err != nil {
+		return err
+	}
+
+	cmd := exec.Command("gofmt")
+	cmd.Stdin = buf
+	cmd.Stdout = f
+	cmd.Stderr = os.Stderr
+	cmdErr := cmd.Run()
+
+	if err := f.Close(); err != nil {
+		return err
+	}
+	if cmdErr != nil {
+		os.Remove(f.Name())
+		return cmdErr
+	}
+
+	return nil
+}
+
+const fileTemplate = `// Copyright 2019 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.
+
+// Code generated by genflags.go — DO NOT EDIT.
+
+package test
+
+// passFlagToTest contains the flags that should be forwarded to
+// the test binary with the prefix "test.".
+var passFlagToTest = map[string]bool {
+{{- range .testFlags}}
+	"{{.}}": true,
+{{- end }}
+}
+
+var passAnalyzersToVet = map[string]bool {
+{{- range .vetAnalyzers}}
+	"{{.}}": true,
+{{- end }}
+}
+`
diff --git a/src/cmd/go/internal/test/internal/genflags/testflag.go b/src/cmd/go/internal/test/internal/genflags/testflag.go
new file mode 100644
index 0000000..712428d
--- /dev/null
+++ b/src/cmd/go/internal/test/internal/genflags/testflag.go
@@ -0,0 +1,35 @@
+// Copyright 2023 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 genflags
+
+import (
+	"flag"
+	"strings"
+	"testing"
+)
+
+// ShortTestFlags returns the set of "-test." flag shorthand names that end
+// users may pass to 'go test'.
+func ShortTestFlags() []string {
+	testing.Init()
+
+	var names []string
+	flag.VisitAll(func(f *flag.Flag) {
+		var name string
+		var found bool
+		if name, found = strings.CutPrefix(f.Name, "test."); !found {
+			return
+		}
+
+		switch name {
+		case "testlogfile", "paniconexit0", "fuzzcachedir", "fuzzworker", "gocoverdir":
+			// These flags are only for use by cmd/go.
+		default:
+			names = append(names, name)
+		}
+	})
+
+	return names
+}
diff --git a/src/cmd/go/internal/test/internal/genflags/vetflag.go b/src/cmd/go/internal/test/internal/genflags/vetflag.go
new file mode 100644
index 0000000..1448811
--- /dev/null
+++ b/src/cmd/go/internal/test/internal/genflags/vetflag.go
@@ -0,0 +1,68 @@
+// Copyright 2019 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 genflags
+
+import (
+	"bytes"
+	"cmd/go/internal/base"
+	"encoding/json"
+	"fmt"
+	"os/exec"
+	"regexp"
+	"sort"
+)
+
+// VetAnalyzers computes analyzers and their aliases supported by vet.
+func VetAnalyzers() ([]string, error) {
+	// get supported vet flag information
+	tool := base.Tool("vet")
+	vetcmd := exec.Command(tool, "-flags")
+	out := new(bytes.Buffer)
+	vetcmd.Stdout = out
+	if err := vetcmd.Run(); err != nil {
+		return nil, fmt.Errorf("go vet: can't execute %s -flags: %v\n", tool, err)
+	}
+	var analysisFlags []struct {
+		Name  string
+		Bool  bool
+		Usage string
+	}
+	if err := json.Unmarshal(out.Bytes(), &analysisFlags); err != nil {
+		return nil, fmt.Errorf("go vet: can't unmarshal JSON from %s -flags: %v", tool, err)
+	}
+
+	// parse the flags to figure out which ones stand for analyses
+	analyzerSet := make(map[string]bool)
+	rEnable := regexp.MustCompile("^enable .+ analysis$")
+	for _, flag := range analysisFlags {
+		if rEnable.MatchString(flag.Usage) {
+			analyzerSet[flag.Name] = true
+		}
+	}
+
+	rDeprecated := regexp.MustCompile("^deprecated alias for -(?P<analyzer>(.+))$")
+	// Returns the original value matched by rDeprecated on input value.
+	// If there is no match, "" is returned.
+	originalValue := func(value string) string {
+		match := rDeprecated.FindStringSubmatch(value)
+		if len(match) < 2 {
+			return ""
+		}
+		return match[1]
+	}
+	// extract deprecated aliases for existing analyses
+	for _, flag := range analysisFlags {
+		if o := originalValue(flag.Usage); analyzerSet[o] {
+			analyzerSet[flag.Name] = true
+		}
+	}
+
+	var analyzers []string
+	for a := range analyzerSet {
+		analyzers = append(analyzers, a)
+	}
+	sort.Strings(analyzers)
+	return analyzers, nil
+}
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
new file mode 100644
index 0000000..8a40547
--- /dev/null
+++ b/src/cmd/go/internal/test/test.go
@@ -0,0 +1,2098 @@
+// Copyright 2011 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 test
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"internal/coverage"
+	"internal/platform"
+	"io"
+	"io/fs"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"slices"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"cmd/go/internal/base"
+	"cmd/go/internal/cache"
+	"cmd/go/internal/cfg"
+	"cmd/go/internal/load"
+	"cmd/go/internal/lockedfile"
+	"cmd/go/internal/modload"
+	"cmd/go/internal/search"
+	"cmd/go/internal/str"
+	"cmd/go/internal/trace"
+	"cmd/go/internal/work"
+	"cmd/internal/test2json"
+
+	"golang.org/x/mod/module"
+)
+
+// Break init loop.
+func init() {
+	CmdTest.Run = runTest
+}
+
+const testUsage = "go test [build/test flags] [packages] [build/test flags & test binary flags]"
+
+var CmdTest = &base.Command{
+	CustomFlags: true,
+	UsageLine:   testUsage,
+	Short:       "test packages",
+	Long: `
+'Go test' automates testing the packages named by the import paths.
+It prints a summary of the test results in the format:
+
+	ok   archive/tar   0.011s
+	FAIL archive/zip   0.022s
+	ok   compress/gzip 0.033s
+	...
+
+followed by detailed output for each failed package.
+
+'Go test' recompiles each package along with any files with names matching
+the file pattern "*_test.go".
+These additional files can contain test functions, benchmark functions, fuzz
+tests and example functions. See 'go help testfunc' for more.
+Each listed package causes the execution of a separate test binary.
+Files whose names begin with "_" (including "_test.go") or "." are ignored.
+
+Test files that declare a package with the suffix "_test" will be compiled as a
+separate package, and then linked and run with the main test binary.
+
+The go tool will ignore a directory named "testdata", making it available
+to hold ancillary data needed by the tests.
+
+As part of building a test binary, go test runs go vet on the package
+and its test source files to identify significant problems. If go vet
+finds any problems, go test reports those and does not run the test
+binary. Only a high-confidence subset of the default go vet checks are
+used. That subset is: atomic, bool, buildtags, directive, errorsas,
+ifaceassert, nilfunc, printf, and stringintconv. You can see
+the documentation for these and other vet tests via "go doc cmd/vet".
+To disable the running of go vet, use the -vet=off flag. To run all
+checks, use the -vet=all flag.
+
+All test output and summary lines are printed to the go command's
+standard output, even if the test printed them to its own standard
+error. (The go command's standard error is reserved for printing
+errors building the tests.)
+
+The go command places $GOROOT/bin at the beginning of $PATH
+in the test's environment, so that tests that execute
+'go' commands use the same 'go' as the parent 'go test' command.
+
+Go test runs in two different modes:
+
+The first, called local directory mode, occurs when go test is
+invoked with no package arguments (for example, 'go test' or 'go
+test -v'). In this mode, go test compiles the package sources and
+tests found in the current directory and then runs the resulting
+test binary. In this mode, caching (discussed below) is disabled.
+After the package test finishes, go test prints a summary line
+showing the test status ('ok' or 'FAIL'), package name, and elapsed
+time.
+
+The second, called package list mode, occurs when go test is invoked
+with explicit package arguments (for example 'go test math', 'go
+test ./...', and even 'go test .'). In this mode, go test compiles
+and tests each of the packages listed on the command line. If a
+package test passes, go test prints only the final 'ok' summary
+line. If a package test fails, go test prints the full test output.
+If invoked with the -bench or -v flag, go test prints the full
+output even for passing package tests, in order to display the
+requested benchmark results or verbose logging. After the package
+tests for all of the listed packages finish, and their output is
+printed, go test prints a final 'FAIL' status if any package test
+has failed.
+
+In package list mode only, go test caches successful package test
+results to avoid unnecessary repeated running of tests. When the
+result of a test can be recovered from the cache, go test will
+redisplay the previous output instead of running the test binary
+again. When this happens, go test prints '(cached)' in place of the
+elapsed time in the summary line.
+
+The rule for a match in the cache is that the run involves the same
+test binary and the flags on the command line come entirely from a
+restricted set of 'cacheable' test flags, defined as -benchtime, -cpu,
+-list, -parallel, -run, -short, -timeout, -failfast, and -v.
+If a run of go test has any test or non-test flags outside this set,
+the result is not cached. To disable test caching, use any test flag
+or argument other than the cacheable flags. The idiomatic way to disable
+test caching explicitly is to use -count=1. Tests that open files within
+the package's source root (usually $GOPATH) or that consult environment
+variables only match future runs in which the files and environment
+variables are unchanged. A cached test result is treated as executing
+in no time at all, so a successful package test result will be cached and
+reused regardless of -timeout setting.
+
+In addition to the build flags, the flags handled by 'go test' itself are:
+
+	-args
+	    Pass the remainder of the command line (everything after -args)
+	    to the test binary, uninterpreted and unchanged.
+	    Because this flag consumes the remainder of the command line,
+	    the package list (if present) must appear before this flag.
+
+	-c
+	    Compile the test binary to pkg.test in the current directory but do not run it
+	    (where pkg is the last element of the package's import path).
+	    The file name or target directory can be changed with the -o flag.
+
+	-exec xprog
+	    Run the test binary using xprog. The behavior is the same as
+	    in 'go run'. See 'go help run' for details.
+
+	-json
+	    Convert test output to JSON suitable for automated processing.
+	    See 'go doc test2json' for the encoding details.
+
+	-o file
+	    Compile the test binary to the named file.
+	    The test still runs (unless -c or -i is specified).
+	    If file ends in a slash or names an existing directory,
+	    the test is written to pkg.test in that directory.
+
+The test binary also accepts flags that control execution of the test; these
+flags are also accessible by 'go test'. See 'go help testflag' for details.
+
+For more about build flags, see 'go help build'.
+For more about specifying packages, see 'go help packages'.
+
+See also: go build, go vet.
+`,
+}
+
+var HelpTestflag = &base.Command{
+	UsageLine: "testflag",
+	Short:     "testing flags",
+	Long: `
+The 'go test' command takes both flags that apply to 'go test' itself
+and flags that apply to the resulting test binary.
+
+Several of the flags control profiling and write an execution profile
+suitable for "go tool pprof"; run "go tool pprof -h" for more
+information. The --alloc_space, --alloc_objects, and --show_bytes
+options of pprof control how the information is presented.
+
+The following flags are recognized by the 'go test' command and
+control the execution of any test:
+
+	-bench regexp
+	    Run only those benchmarks matching a regular expression.
+	    By default, no benchmarks are run.
+	    To run all benchmarks, use '-bench .' or '-bench=.'.
+	    The regular expression is split by unbracketed slash (/)
+	    characters into a sequence of regular expressions, and each
+	    part of a benchmark's identifier must match the corresponding
+	    element in the sequence, if any. Possible parents of matches
+	    are run with b.N=1 to identify sub-benchmarks. For example,
+	    given -bench=X/Y, top-level benchmarks matching X are run
+	    with b.N=1 to find any sub-benchmarks matching Y, which are
+	    then run in full.
+
+	-benchtime t
+	    Run enough iterations of each benchmark to take t, specified
+	    as a time.Duration (for example, -benchtime 1h30s).
+	    The default is 1 second (1s).
+	    The special syntax Nx means to run the benchmark N times
+	    (for example, -benchtime 100x).
+
+	-count n
+	    Run each test, benchmark, and fuzz seed n times (default 1).
+	    If -cpu is set, run n times for each GOMAXPROCS value.
+	    Examples are always run once. -count does not apply to
+	    fuzz tests matched by -fuzz.
+
+	-cover
+	    Enable coverage analysis.
+	    Note that because coverage works by annotating the source
+	    code before compilation, compilation and test failures with
+	    coverage enabled may report line numbers that don't correspond
+	    to the original sources.
+
+	-covermode set,count,atomic
+	    Set the mode for coverage analysis for the package[s]
+	    being tested. The default is "set" unless -race is enabled,
+	    in which case it is "atomic".
+	    The values:
+		set: bool: does this statement run?
+		count: int: how many times does this statement run?
+		atomic: int: count, but correct in multithreaded tests;
+			significantly more expensive.
+	    Sets -cover.
+
+	-coverpkg pattern1,pattern2,pattern3
+	    Apply coverage analysis in each test to packages matching the patterns.
+	    The default is for each test to analyze only the package being tested.
+	    See 'go help packages' for a description of package patterns.
+	    Sets -cover.
+
+	-cpu 1,2,4
+	    Specify a list of GOMAXPROCS values for which the tests, benchmarks or
+	    fuzz tests should be executed. The default is the current value
+	    of GOMAXPROCS. -cpu does not apply to fuzz tests matched by -fuzz.
+
+	-failfast
+	    Do not start new tests after the first test failure.
+
+	-fullpath
+	    Show full file names in the error messages.
+
+	-fuzz regexp
+	    Run the fuzz test matching the regular expression. When specified,
+	    the command line argument must match exactly one package within the
+	    main module, and regexp must match exactly one fuzz test within
+	    that package. Fuzzing will occur after tests, benchmarks, seed corpora
+	    of other fuzz tests, and examples have completed. See the Fuzzing
+	    section of the testing package documentation for details.
+
+	-fuzztime t
+	    Run enough iterations of the fuzz target during fuzzing to take t,
+	    specified as a time.Duration (for example, -fuzztime 1h30s).
+		The default is to run forever.
+	    The special syntax Nx means to run the fuzz target N times
+	    (for example, -fuzztime 1000x).
+
+	-fuzzminimizetime t
+	    Run enough iterations of the fuzz target during each minimization
+	    attempt to take t, as specified as a time.Duration (for example,
+	    -fuzzminimizetime 30s).
+		The default is 60s.
+	    The special syntax Nx means to run the fuzz target N times
+	    (for example, -fuzzminimizetime 100x).
+
+	-json
+	    Log verbose output and test results in JSON. This presents the
+	    same information as the -v flag in a machine-readable format.
+
+	-list regexp
+	    List tests, benchmarks, fuzz tests, or examples matching the regular
+	    expression. No tests, benchmarks, fuzz tests, or examples will be run.
+	    This will only list top-level tests. No subtest or subbenchmarks will be
+	    shown.
+
+	-parallel n
+	    Allow parallel execution of test functions that call t.Parallel, and
+	    fuzz targets that call t.Parallel when running the seed corpus.
+	    The value of this flag is the maximum number of tests to run
+	    simultaneously.
+	    While fuzzing, the value of this flag is the maximum number of
+	    subprocesses that may call the fuzz function simultaneously, regardless of
+	    whether T.Parallel is called.
+	    By default, -parallel is set to the value of GOMAXPROCS.
+	    Setting -parallel to values higher than GOMAXPROCS may cause degraded
+	    performance due to CPU contention, especially when fuzzing.
+	    Note that -parallel only applies within a single test binary.
+	    The 'go test' command may run tests for different packages
+	    in parallel as well, according to the setting of the -p flag
+	    (see 'go help build').
+
+	-run regexp
+	    Run only those tests, examples, and fuzz tests matching the regular
+	    expression. For tests, the regular expression is split by unbracketed
+	    slash (/) characters into a sequence of regular expressions, and each
+	    part of a test's identifier must match the corresponding element in
+	    the sequence, if any. Note that possible parents of matches are
+	    run too, so that -run=X/Y matches and runs and reports the result
+	    of all tests matching X, even those without sub-tests matching Y,
+	    because it must run them to look for those sub-tests.
+	    See also -skip.
+
+	-short
+	    Tell long-running tests to shorten their run time.
+	    It is off by default but set during all.bash so that installing
+	    the Go tree can run a sanity check but not spend time running
+	    exhaustive tests.
+
+	-shuffle off,on,N
+	    Randomize the execution order of tests and benchmarks.
+	    It is off by default. If -shuffle is set to on, then it will seed
+	    the randomizer using the system clock. If -shuffle is set to an
+	    integer N, then N will be used as the seed value. In both cases,
+	    the seed will be reported for reproducibility.
+
+	-skip regexp
+	    Run only those tests, examples, fuzz tests, and benchmarks that
+	    do not match the regular expression. Like for -run and -bench,
+	    for tests and benchmarks, the regular expression is split by unbracketed
+	    slash (/) characters into a sequence of regular expressions, and each
+	    part of a test's identifier must match the corresponding element in
+	    the sequence, if any.
+
+	-timeout d
+	    If a test binary runs longer than duration d, panic.
+	    If d is 0, the timeout is disabled.
+	    The default is 10 minutes (10m).
+
+	-v
+	    Verbose output: log all tests as they are run. Also print all
+	    text from Log and Logf calls even if the test succeeds.
+
+	-vet list
+	    Configure the invocation of "go vet" during "go test"
+	    to use the comma-separated list of vet checks.
+	    If list is empty, "go test" runs "go vet" with a curated list of
+	    checks believed to be always worth addressing.
+	    If list is "off", "go test" does not run "go vet" at all.
+
+The following flags are also recognized by 'go test' and can be used to
+profile the tests during execution:
+
+	-benchmem
+	    Print memory allocation statistics for benchmarks.
+
+	-blockprofile block.out
+	    Write a goroutine blocking profile to the specified file
+	    when all tests are complete.
+	    Writes test binary as -c would.
+
+	-blockprofilerate n
+	    Control the detail provided in goroutine blocking profiles by
+	    calling runtime.SetBlockProfileRate with n.
+	    See 'go doc runtime.SetBlockProfileRate'.
+	    The profiler aims to sample, on average, one blocking event every
+	    n nanoseconds the program spends blocked. By default,
+	    if -test.blockprofile is set without this flag, all blocking events
+	    are recorded, equivalent to -test.blockprofilerate=1.
+
+	-coverprofile cover.out
+	    Write a coverage profile to the file after all tests have passed.
+	    Sets -cover.
+
+	-cpuprofile cpu.out
+	    Write a CPU profile to the specified file before exiting.
+	    Writes test binary as -c would.
+
+	-memprofile mem.out
+	    Write an allocation profile to the file after all tests have passed.
+	    Writes test binary as -c would.
+
+	-memprofilerate n
+	    Enable more precise (and expensive) memory allocation profiles by
+	    setting runtime.MemProfileRate. See 'go doc runtime.MemProfileRate'.
+	    To profile all memory allocations, use -test.memprofilerate=1.
+
+	-mutexprofile mutex.out
+	    Write a mutex contention profile to the specified file
+	    when all tests are complete.
+	    Writes test binary as -c would.
+
+	-mutexprofilefraction n
+	    Sample 1 in n stack traces of goroutines holding a
+	    contended mutex.
+
+	-outputdir directory
+	    Place output files from profiling in the specified directory,
+	    by default the directory in which "go test" is running.
+
+	-trace trace.out
+	    Write an execution trace to the specified file before exiting.
+
+Each of these flags is also recognized with an optional 'test.' prefix,
+as in -test.v. When invoking the generated test binary (the result of
+'go test -c') directly, however, the prefix is mandatory.
+
+The 'go test' command rewrites or removes recognized flags,
+as appropriate, both before and after the optional package list,
+before invoking the test binary.
+
+For instance, the command
+
+	go test -v -myflag testdata -cpuprofile=prof.out -x
+
+will compile the test binary and then run it as
+
+	pkg.test -test.v -myflag testdata -test.cpuprofile=prof.out
+
+(The -x flag is removed because it applies only to the go command's
+execution, not to the test itself.)
+
+The test flags that generate profiles (other than for coverage) also
+leave the test binary in pkg.test for use when analyzing the profiles.
+
+When 'go test' runs a test binary, it does so from within the
+corresponding package's source code directory. Depending on the test,
+it may be necessary to do the same when invoking a generated test
+binary directly. Because that directory may be located within the
+module cache, which may be read-only and is verified by checksums, the
+test must not write to it or any other directory within the module
+unless explicitly requested by the user (such as with the -fuzz flag,
+which writes failures to testdata/fuzz).
+
+The command-line package list, if present, must appear before any
+flag not known to the go test command. Continuing the example above,
+the package list would have to appear before -myflag, but could appear
+on either side of -v.
+
+When 'go test' runs in package list mode, 'go test' caches successful
+package test results to avoid unnecessary repeated running of tests. To
+disable test caching, use any test flag or argument other than the
+cacheable flags. The idiomatic way to disable test caching explicitly
+is to use -count=1.
+
+To keep an argument for a test binary from being interpreted as a
+known flag or a package name, use -args (see 'go help test') which
+passes the remainder of the command line through to the test binary
+uninterpreted and unaltered.
+
+For instance, the command
+
+	go test -v -args -x -v
+
+will compile the test binary and then run it as
+
+	pkg.test -test.v -x -v
+
+Similarly,
+
+	go test -args math
+
+will compile the test binary and then run it as
+
+	pkg.test math
+
+In the first example, the -x and the second -v are passed through to the
+test binary unchanged and with no effect on the go command itself.
+In the second example, the argument math is passed through to the test
+binary, instead of being interpreted as the package list.
+`,
+}
+
+var HelpTestfunc = &base.Command{
+	UsageLine: "testfunc",
+	Short:     "testing functions",
+	Long: `
+The 'go test' command expects to find test, benchmark, and example functions
+in the "*_test.go" files corresponding to the package under test.
+
+A test function is one named TestXxx (where Xxx does not start with a
+lower case letter) and should have the signature,
+
+	func TestXxx(t *testing.T) { ... }
+
+A benchmark function is one named BenchmarkXxx and should have the signature,
+
+	func BenchmarkXxx(b *testing.B) { ... }
+
+A fuzz test is one named FuzzXxx and should have the signature,
+
+	func FuzzXxx(f *testing.F) { ... }
+
+An example function is similar to a test function but, instead of using
+*testing.T to report success or failure, prints output to os.Stdout.
+If the last comment in the function starts with "Output:" then the output
+is compared exactly against the comment (see examples below). If the last
+comment begins with "Unordered output:" then the output is compared to the
+comment, however the order of the lines is ignored. An example with no such
+comment is compiled but not executed. An example with no text after
+"Output:" is compiled, executed, and expected to produce no output.
+
+Godoc displays the body of ExampleXxx to demonstrate the use
+of the function, constant, or variable Xxx. An example of a method M with
+receiver type T or *T is named ExampleT_M. There may be multiple examples
+for a given function, constant, or variable, distinguished by a trailing _xxx,
+where xxx is a suffix not beginning with an upper case letter.
+
+Here is an example of an example:
+
+	func ExamplePrintln() {
+		Println("The output of\nthis example.")
+		// Output: The output of
+		// this example.
+	}
+
+Here is another example where the ordering of the output is ignored:
+
+	func ExamplePerm() {
+		for _, value := range Perm(4) {
+			fmt.Println(value)
+		}
+
+		// Unordered output: 4
+		// 2
+		// 1
+		// 3
+		// 0
+	}
+
+The entire test file is presented as the example when it contains a single
+example function, at least one other function, type, variable, or constant
+declaration, and no tests, benchmarks, or fuzz tests.
+
+See the documentation of the testing package for more information.
+`,
+}
+
+var (
+	testBench        string                            // -bench flag
+	testC            bool                              // -c flag
+	testCoverPkgs    []*load.Package                   // -coverpkg flag
+	testCoverProfile string                            // -coverprofile flag
+	testFuzz         string                            // -fuzz flag
+	testJSON         bool                              // -json flag
+	testList         string                            // -list flag
+	testO            string                            // -o flag
+	testOutputDir    outputdirFlag                     // -outputdir flag
+	testShuffle      shuffleFlag                       // -shuffle flag
+	testTimeout      time.Duration                     // -timeout flag
+	testV            testVFlag                         // -v flag
+	testVet          = vetFlag{flags: defaultVetFlags} // -vet flag
+)
+
+type testVFlag struct {
+	on   bool // -v is set in some form
+	json bool // -v=test2json is set, to make output better for test2json
+}
+
+func (*testVFlag) IsBoolFlag() bool { return true }
+
+func (f *testVFlag) Set(arg string) error {
+	if v, err := strconv.ParseBool(arg); err == nil {
+		f.on = v
+		f.json = false
+		return nil
+	}
+	if arg == "test2json" {
+		f.on = true
+		f.json = arg == "test2json"
+		return nil
+	}
+	return fmt.Errorf("invalid flag -test.v=%s", arg)
+}
+
+func (f *testVFlag) String() string {
+	if f.json {
+		return "test2json"
+	}
+	if f.on {
+		return "true"
+	}
+	return "false"
+}
+
+var (
+	testArgs []string
+	pkgArgs  []string
+	pkgs     []*load.Package
+
+	testHelp bool // -help option passed to test via -args
+
+	testKillTimeout = 100 * 365 * 24 * time.Hour // backup alarm; defaults to about a century if no timeout is set
+	testWaitDelay   time.Duration                // how long to wait for output to close after a test binary exits; zero means unlimited
+	testCacheExpire time.Time                    // ignore cached test results before this time
+
+	testBlockProfile, testCPUProfile, testMemProfile, testMutexProfile, testTrace string // profiling flag that limits test to one package
+
+	testODir = false
+)
+
+// testProfile returns the name of an arbitrary single-package profiling flag
+// that is set, if any.
+func testProfile() string {
+	switch {
+	case testBlockProfile != "":
+		return "-blockprofile"
+	case testCPUProfile != "":
+		return "-cpuprofile"
+	case testMemProfile != "":
+		return "-memprofile"
+	case testMutexProfile != "":
+		return "-mutexprofile"
+	case testTrace != "":
+		return "-trace"
+	default:
+		return ""
+	}
+}
+
+// testNeedBinary reports whether the test needs to keep the binary around.
+func testNeedBinary() bool {
+	switch {
+	case testBlockProfile != "":
+		return true
+	case testCPUProfile != "":
+		return true
+	case testMemProfile != "":
+		return true
+	case testMutexProfile != "":
+		return true
+	case testO != "":
+		return true
+	default:
+		return false
+	}
+}
+
+// testShowPass reports whether the output for a passing test should be shown.
+func testShowPass() bool {
+	return testV.on || testList != "" || testHelp
+}
+
+var defaultVetFlags = []string{
+	// TODO(rsc): Decide which tests are enabled by default.
+	// See golang.org/issue/18085.
+	// "-asmdecl",
+	// "-assign",
+	"-atomic",
+	"-bool",
+	"-buildtags",
+	// "-cgocall",
+	// "-composites",
+	// "-copylocks",
+	"-directive",
+	"-errorsas",
+	// "-httpresponse",
+	"-ifaceassert",
+	// "-lostcancel",
+	// "-methods",
+	"-nilfunc",
+	"-printf",
+	// "-rangeloops",
+	// "-shift",
+	"-slog",
+	"-stringintconv",
+	// "-structtags",
+	// "-tests",
+	// "-unreachable",
+	// "-unsafeptr",
+	// "-unusedresult",
+}
+
+func runTest(ctx context.Context, cmd *base.Command, args []string) {
+	pkgArgs, testArgs = testFlags(args)
+	modload.InitWorkfile() // The test command does custom flag processing; initialize workspaces after that.
+
+	if cfg.DebugTrace != "" {
+		var close func() error
+		var err error
+		ctx, close, err = trace.Start(ctx, cfg.DebugTrace)
+		if err != nil {
+			base.Fatalf("failed to start trace: %v", err)
+		}
+		defer func() {
+			if err := close(); err != nil {
+				base.Fatalf("failed to stop trace: %v", err)
+			}
+		}()
+	}
+
+	ctx, span := trace.StartSpan(ctx, fmt.Sprint("Running ", cmd.Name(), " command"))
+	defer span.Done()
+
+	work.FindExecCmd() // initialize cached result
+
+	work.BuildInit()
+	work.VetFlags = testVet.flags
+	work.VetExplicit = testVet.explicit
+
+	pkgOpts := load.PackageOpts{ModResolveTests: true}
+	pkgs = load.PackagesAndErrors(ctx, pkgOpts, pkgArgs)
+	load.CheckPackageErrors(pkgs)
+	if len(pkgs) == 0 {
+		base.Fatalf("no packages to test")
+	}
+
+	if testFuzz != "" {
+		if !platform.FuzzSupported(cfg.Goos, cfg.Goarch) {
+			base.Fatalf("-fuzz flag is not supported on %s/%s", cfg.Goos, cfg.Goarch)
+		}
+		if len(pkgs) != 1 {
+			base.Fatalf("cannot use -fuzz flag with multiple packages")
+		}
+		if testCoverProfile != "" {
+			base.Fatalf("cannot use -coverprofile flag with -fuzz flag")
+		}
+		if profileFlag := testProfile(); profileFlag != "" {
+			base.Fatalf("cannot use %s flag with -fuzz flag", profileFlag)
+		}
+
+		// Reject the '-fuzz' flag if the package is outside the main module.
+		// Otherwise, if fuzzing identifies a failure it could corrupt checksums in
+		// the module cache (or permanently alter the behavior of std tests for all
+		// users) by writing the failing input to the package's testdata directory.
+		// (See https://golang.org/issue/48495 and test_fuzz_modcache.txt.)
+		mainMods := modload.MainModules
+		if m := pkgs[0].Module; m != nil && m.Path != "" {
+			if !mainMods.Contains(m.Path) {
+				base.Fatalf("cannot use -fuzz flag on package outside the main module")
+			}
+		} else if pkgs[0].Standard && modload.Enabled() {
+			// Because packages in 'std' and 'cmd' are part of the standard library,
+			// they are only treated as part of a module in 'go mod' subcommands and
+			// 'go get'. However, we still don't want to accidentally corrupt their
+			// testdata during fuzzing, nor do we want to fail with surprising errors
+			// if GOROOT isn't writable (as is often the case for Go toolchains
+			// installed through package managers).
+			//
+			// If the user is requesting to fuzz a standard-library package, ensure
+			// that they are in the same module as that package (just like when
+			// fuzzing any other package).
+			if strings.HasPrefix(pkgs[0].ImportPath, "cmd/") {
+				if !mainMods.Contains("cmd") || !mainMods.InGorootSrc(module.Version{Path: "cmd"}) {
+					base.Fatalf("cannot use -fuzz flag on package outside the main module")
+				}
+			} else {
+				if !mainMods.Contains("std") || !mainMods.InGorootSrc(module.Version{Path: "std"}) {
+					base.Fatalf("cannot use -fuzz flag on package outside the main module")
+				}
+			}
+		}
+	}
+	if testProfile() != "" && len(pkgs) != 1 {
+		base.Fatalf("cannot use %s flag with multiple packages", testProfile())
+	}
+
+	if testO != "" {
+		if strings.HasSuffix(testO, "/") || strings.HasSuffix(testO, string(os.PathSeparator)) {
+			testODir = true
+		} else if fi, err := os.Stat(testO); err == nil && fi.IsDir() {
+			testODir = true
+		}
+	}
+
+	if len(pkgs) > 1 && (testC || testO != "") && !base.IsNull(testO) {
+		if testO != "" && !testODir {
+			base.Fatalf("with multiple packages, -o must refer to a directory or %s", os.DevNull)
+		}
+
+		pkgsForBinary := map[string][]*load.Package{}
+
+		for _, p := range pkgs {
+			testBinary := testBinaryName(p)
+			pkgsForBinary[testBinary] = append(pkgsForBinary[testBinary], p)
+		}
+
+		for testBinary, pkgs := range pkgsForBinary {
+			if len(pkgs) > 1 {
+				var buf strings.Builder
+				for _, pkg := range pkgs {
+					buf.WriteString(pkg.ImportPath)
+					buf.WriteString("\n")
+				}
+
+				base.Errorf("cannot write test binary %s for multiple packages:\n%s", testBinary, buf.String())
+			}
+		}
+
+		base.ExitIfErrors()
+	}
+
+	initCoverProfile()
+	defer closeCoverProfile()
+
+	// If a test timeout is finite, set our kill timeout
+	// to that timeout plus one minute. This is a backup alarm in case
+	// the test wedges with a goroutine spinning and its background
+	// timer does not get a chance to fire.
+	// Don't set this if fuzzing, since it should be able to run
+	// indefinitely.
+	if testTimeout > 0 && testFuzz == "" {
+		// The WaitDelay for the test process depends on both the OS I/O and
+		// scheduling overhead and the amount of I/O generated by the test just
+		// before it exits. We set the minimum at 5 seconds to account for the OS
+		// overhead, and scale it up from there proportional to the overall test
+		// timeout on the assumption that the time to write and read a goroutine
+		// dump from a timed-out test process scales roughly with the overall
+		// running time of the test.
+		//
+		// This is probably too generous when the timeout is very long, but it seems
+		// better to hard-code a scale factor than to hard-code a constant delay.
+		if wd := testTimeout / 10; wd < 5*time.Second {
+			testWaitDelay = 5 * time.Second
+		} else {
+			testWaitDelay = wd
+		}
+
+		// We expect the test binary to terminate itself (and dump stacks) after
+		// exactly testTimeout. We give it up to one WaitDelay or one minute,
+		// whichever is longer, to finish dumping stacks before we send it an
+		// external signal: if the process has a lot of goroutines, dumping stacks
+		// after the timeout can take a while.
+		//
+		// After the signal is delivered, the test process may have up to one
+		// additional WaitDelay to finish writing its output streams.
+		if testWaitDelay < 1*time.Minute {
+			testKillTimeout = testTimeout + 1*time.Minute
+		} else {
+			testKillTimeout = testTimeout + testWaitDelay
+		}
+	}
+
+	// Read testcache expiration time, if present.
+	// (We implement go clean -testcache by writing an expiration date
+	// instead of searching out and deleting test result cache entries.)
+	if dir := cache.DefaultDir(); dir != "off" {
+		if data, _ := lockedfile.Read(filepath.Join(dir, "testexpire.txt")); len(data) > 0 && data[len(data)-1] == '\n' {
+			if t, err := strconv.ParseInt(string(data[:len(data)-1]), 10, 64); err == nil {
+				testCacheExpire = time.Unix(0, t)
+			}
+		}
+	}
+
+	b := work.NewBuilder("")
+	defer func() {
+		if err := b.Close(); err != nil {
+			base.Fatal(err)
+		}
+	}()
+
+	var builds, runs, prints []*work.Action
+	var writeCoverMetaAct *work.Action
+
+	if cfg.BuildCoverPkg != nil {
+		match := make([]func(*load.Package) bool, len(cfg.BuildCoverPkg))
+		for i := range cfg.BuildCoverPkg {
+			match[i] = load.MatchPackage(cfg.BuildCoverPkg[i], base.Cwd())
+		}
+
+		// Select for coverage all dependencies matching the -coverpkg
+		// patterns.
+		plist := load.TestPackageList(ctx, pkgOpts, pkgs)
+		testCoverPkgs = load.SelectCoverPackages(plist, match, "test")
+		if cfg.Experiment.CoverageRedesign && len(testCoverPkgs) > 0 {
+			// create a new singleton action that will collect up the
+			// meta-data files from all of the packages mentioned in
+			// "-coverpkg" and write them to a summary file. This new
+			// action will depend on all the build actions for the
+			// test packages, and all the run actions for these
+			// packages will depend on it. Motivating example:
+			// supposed we have a top level directory with three
+			// package subdirs, "a", "b", and "c", and
+			// from the top level, a user runs "go test -coverpkg=./... ./...".
+			// This will result in (roughly) the following action graph:
+			//
+			//	build("a")       build("b")         build("c")
+			//	    |               |                   |
+			//	link("a.test")   link("b.test")     link("c.test")
+			//	    |               |                   |
+			//	run("a.test")    run("b.test")      run("c.test")
+			//	    |               |                   |
+			//	  print          print              print
+			//
+			// When -coverpkg=<pattern> is in effect, we want to
+			// express the coverage percentage for each package as a
+			// fraction of *all* the statements that match the
+			// pattern, hence if "c" doesn't import "a", we need to
+			// pass as meta-data file for "a" (emitted during the
+			// package "a" build) to the package "c" run action, so
+			// that it can be incorporated with "c"'s regular
+			// metadata. To do this, we add edges from each compile
+			// action to a "writeCoverMeta" action, then from the
+			// writeCoverMeta action to each run action. Updated
+			// graph:
+			//
+			//	build("a")       build("b")         build("c")
+			//	    |   \       /   |               /   |
+			//	    |    v     v    |              /    |
+			//	    |   writemeta <-|-------------+     |
+			//	    |         |||   |                   |
+			//	    |         ||\   |                   |
+			//	link("a.test")/\ \  link("b.test")      link("c.test")
+			//	    |        /  \ +-|--------------+    |
+			//	    |       /    \  |               \   |
+			//	    |      v      v |                v  |
+			//	run("a.test")    run("b.test")      run("c.test")
+			//	    |               |                   |
+			//	  print          print              print
+			//
+			writeCoverMetaAct = &work.Action{
+				Mode:   "write coverage meta-data file",
+				Actor:  work.ActorFunc(work.WriteCoverMetaFilesFile),
+				Objdir: b.NewObjdir(),
+			}
+			for _, p := range testCoverPkgs {
+				p.Internal.Cover.GenMeta = true
+			}
+		}
+	}
+
+	// Inform the compiler that it should instrument the binary at
+	// build-time when fuzzing is enabled.
+	if testFuzz != "" {
+		// Don't instrument packages which may affect coverage guidance but are
+		// unlikely to be useful. Most of these are used by the testing or
+		// internal/fuzz packages concurrently with fuzzing.
+		var skipInstrumentation = map[string]bool{
+			"context":       true,
+			"internal/fuzz": true,
+			"reflect":       true,
+			"runtime":       true,
+			"sync":          true,
+			"sync/atomic":   true,
+			"syscall":       true,
+			"testing":       true,
+			"time":          true,
+		}
+		for _, p := range load.TestPackageList(ctx, pkgOpts, pkgs) {
+			if !skipInstrumentation[p.ImportPath] {
+				p.Internal.FuzzInstrument = true
+			}
+		}
+	}
+
+	// Collect all the packages imported by the packages being tested.
+	allImports := make(map[*load.Package]bool)
+	for _, p := range pkgs {
+		if p.Error != nil && p.Error.IsImportCycle {
+			continue
+		}
+		for _, p1 := range p.Internal.Imports {
+			allImports[p1] = true
+		}
+	}
+
+	if cfg.BuildCover {
+		for _, p := range pkgs {
+			// sync/atomic import is inserted by the cover tool if
+			// we're using atomic mode (and not compiling
+			// sync/atomic package itself). See #18486 and #57445.
+			// Note that this needs to be done prior to any of the
+			// builderTest invocations below, due to the fact that
+			// a given package in the 'pkgs' list may import
+			// package Q which appears later in the list (if this
+			// happens we'll wind up building the Q compile action
+			// before updating its deps to include sync/atomic).
+			if cfg.BuildCoverMode == "atomic" && p.ImportPath != "sync/atomic" {
+				load.EnsureImport(p, "sync/atomic")
+			}
+			// Tag the package for static meta-data generation if no
+			// test files (this works only with the new coverage
+			// design). Do this here (as opposed to in builderTest) so
+			// as to handle the case where we're testing multiple
+			// packages and one of the earlier packages imports a
+			// later package. Note that if -coverpkg is in effect
+			// p.Internal.Cover.GenMeta will wind up being set for
+			// all matching packages.
+			if len(p.TestGoFiles)+len(p.XTestGoFiles) == 0 &&
+				cfg.BuildCoverPkg == nil &&
+				cfg.Experiment.CoverageRedesign {
+				p.Internal.Cover.GenMeta = true
+			}
+		}
+	}
+
+	// Prepare build + run + print actions for all packages being tested.
+	for _, p := range pkgs {
+		buildTest, runTest, printTest, err := builderTest(b, ctx, pkgOpts, p, allImports[p], writeCoverMetaAct)
+		if err != nil {
+			str := err.Error()
+			str = strings.TrimPrefix(str, "\n")
+			if p.ImportPath != "" {
+				base.Errorf("# %s\n%s", p.ImportPath, str)
+			} else {
+				base.Errorf("%s", str)
+			}
+			fmt.Printf("FAIL\t%s [setup failed]\n", p.ImportPath)
+			continue
+		}
+		builds = append(builds, buildTest)
+		runs = append(runs, runTest)
+		prints = append(prints, printTest)
+	}
+
+	// Order runs for coordinating start JSON prints.
+	ch := make(chan struct{})
+	close(ch)
+	for _, a := range runs {
+		if r, ok := a.Actor.(*runTestActor); ok {
+			r.prev = ch
+			ch = make(chan struct{})
+			r.next = ch
+		}
+	}
+
+	// Ultimately the goal is to print the output.
+	root := &work.Action{Mode: "go test", Actor: work.ActorFunc(printExitStatus), Deps: prints}
+
+	// Force the printing of results to happen in order,
+	// one at a time.
+	for i, a := range prints {
+		if i > 0 {
+			a.Deps = append(a.Deps, prints[i-1])
+		}
+	}
+
+	// Force benchmarks to run in serial.
+	if !testC && (testBench != "") {
+		// The first run must wait for all builds.
+		// Later runs must wait for the previous run's print.
+		for i, run := range runs {
+			if i == 0 {
+				run.Deps = append(run.Deps, builds...)
+			} else {
+				run.Deps = append(run.Deps, prints[i-1])
+			}
+		}
+	}
+
+	b.Do(ctx, root)
+}
+
+var windowsBadWords = []string{
+	"install",
+	"patch",
+	"setup",
+	"update",
+}
+
+func builderTest(b *work.Builder, ctx context.Context, pkgOpts load.PackageOpts, p *load.Package, imported bool, writeCoverMetaAct *work.Action) (buildAction, runAction, printAction *work.Action, err error) {
+	if len(p.TestGoFiles)+len(p.XTestGoFiles) == 0 {
+		if cfg.BuildCover && cfg.Experiment.CoverageRedesign {
+			if p.Internal.Cover.GenMeta {
+				p.Internal.Cover.Mode = cfg.BuildCoverMode
+			}
+		}
+		build := b.CompileAction(work.ModeBuild, work.ModeBuild, p)
+		run := &work.Action{
+			Mode:       "test run",
+			Actor:      new(runTestActor),
+			Deps:       []*work.Action{build},
+			Objdir:     b.NewObjdir(),
+			Package:    p,
+			IgnoreFail: true, // run (prepare output) even if build failed
+		}
+		if writeCoverMetaAct != nil {
+			// There is no real "run" for this package (since there
+			// are no tests), but if coverage is turned on, we can
+			// collect coverage data for the code in the package by
+			// asking cmd/cover for a static meta-data file as part of
+			// the package build. This static meta-data file is then
+			// consumed by a pseudo-action (writeCoverMetaAct) that
+			// adds it to a summary file, then this summary file is
+			// consumed by the various "run test" actions. Below we
+			// add a dependence edge between the build action and the
+			// "write meta files" pseudo-action, and then another dep
+			// from writeCoverMetaAct to the run action. See the
+			// comment in runTest() at the definition of
+			// writeCoverMetaAct for more details.
+			run.Deps = append(run.Deps, writeCoverMetaAct)
+			writeCoverMetaAct.Deps = append(writeCoverMetaAct.Deps, build)
+		}
+		addTestVet(b, p, run, nil)
+		print := &work.Action{
+			Mode:       "test print",
+			Actor:      work.ActorFunc(builderPrintTest),
+			Deps:       []*work.Action{run},
+			Package:    p,
+			IgnoreFail: true, // print even if test failed
+		}
+		return build, run, print, nil
+	}
+
+	// Build Package structs describing:
+	//	pmain - pkg.test binary
+	//	ptest - package + test files
+	//	pxtest - package of external test files
+	var cover *load.TestCover
+	if cfg.BuildCover {
+		cover = &load.TestCover{
+			Mode:  cfg.BuildCoverMode,
+			Local: cfg.BuildCoverPkg == nil,
+			Pkgs:  testCoverPkgs,
+			Paths: cfg.BuildCoverPkg,
+		}
+	}
+	pmain, ptest, pxtest, err := load.TestPackagesFor(ctx, pkgOpts, p, cover)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	// If imported is true then this package is imported by some
+	// package being tested. Make building the test version of the
+	// package depend on building the non-test version, so that we
+	// only report build errors once. Issue #44624.
+	if imported && ptest != p {
+		buildTest := b.CompileAction(work.ModeBuild, work.ModeBuild, ptest)
+		buildP := b.CompileAction(work.ModeBuild, work.ModeBuild, p)
+		buildTest.Deps = append(buildTest.Deps, buildP)
+	}
+
+	testBinary := testBinaryName(p)
+
+	testDir := b.NewObjdir()
+	if err := b.BackgroundShell().Mkdir(testDir); err != nil {
+		return nil, nil, nil, err
+	}
+
+	pmain.Dir = testDir
+	pmain.Internal.OmitDebug = !testC && !testNeedBinary()
+	if pmain.ImportPath == "runtime.test" {
+		// The runtime package needs a symbolized binary for its tests.
+		// See runtime/unsafepoint_test.go.
+		pmain.Internal.OmitDebug = false
+	}
+
+	if !cfg.BuildN {
+		// writeTestmain writes _testmain.go,
+		// using the test description gathered in t.
+		if err := os.WriteFile(testDir+"_testmain.go", *pmain.Internal.TestmainGo, 0666); err != nil {
+			return nil, nil, nil, err
+		}
+	}
+
+	// Set compile objdir to testDir we've already created,
+	// so that the default file path stripping applies to _testmain.go.
+	b.CompileAction(work.ModeBuild, work.ModeBuild, pmain).Objdir = testDir
+
+	a := b.LinkAction(work.ModeBuild, work.ModeBuild, pmain)
+	a.Target = testDir + testBinary + cfg.ExeSuffix
+	if cfg.Goos == "windows" {
+		// There are many reserved words on Windows that,
+		// if used in the name of an executable, cause Windows
+		// to try to ask for extra permissions.
+		// The word list includes setup, install, update, and patch,
+		// but it does not appear to be defined anywhere.
+		// We have run into this trying to run the
+		// go.codereview/patch tests.
+		// For package names containing those words, use test.test.exe
+		// instead of pkgname.test.exe.
+		// Note that this file name is only used in the Go command's
+		// temporary directory. If the -c or other flags are
+		// given, the code below will still use pkgname.test.exe.
+		// There are two user-visible effects of this change.
+		// First, you can actually run 'go test' in directories that
+		// have names that Windows thinks are installer-like,
+		// without getting a dialog box asking for more permissions.
+		// Second, in the Windows process listing during go test,
+		// the test shows up as test.test.exe, not pkgname.test.exe.
+		// That second one is a drawback, but it seems a small
+		// price to pay for the test running at all.
+		// If maintaining the list of bad words is too onerous,
+		// we could just do this always on Windows.
+		for _, bad := range windowsBadWords {
+			if strings.Contains(testBinary, bad) {
+				a.Target = testDir + "test.test" + cfg.ExeSuffix
+				break
+			}
+		}
+	}
+	buildAction = a
+	var installAction, cleanAction *work.Action
+	if testC || testNeedBinary() {
+		// -c or profiling flag: create action to copy binary to ./test.out.
+		target := filepath.Join(base.Cwd(), testBinary+cfg.ExeSuffix)
+		isNull := false
+
+		if testO != "" {
+			target = testO
+
+			if testODir {
+				if filepath.IsAbs(target) {
+					target = filepath.Join(target, testBinary+cfg.ExeSuffix)
+				} else {
+					target = filepath.Join(base.Cwd(), target, testBinary+cfg.ExeSuffix)
+				}
+			} else {
+				if base.IsNull(target) {
+					isNull = true
+				} else if !filepath.IsAbs(target) {
+					target = filepath.Join(base.Cwd(), target)
+				}
+			}
+		}
+
+		if isNull {
+			runAction = buildAction
+		} else {
+			pmain.Target = target
+			installAction = &work.Action{
+				Mode:    "test build",
+				Actor:   work.ActorFunc(work.BuildInstallFunc),
+				Deps:    []*work.Action{buildAction},
+				Package: pmain,
+				Target:  target,
+			}
+			runAction = installAction // make sure runAction != nil even if not running test
+		}
+	}
+
+	var vetRunAction *work.Action
+	if testC {
+		printAction = &work.Action{Mode: "test print (nop)", Package: p, Deps: []*work.Action{runAction}} // nop
+		vetRunAction = printAction
+	} else {
+		// run test
+		rta := &runTestActor{
+			writeCoverMetaAct: writeCoverMetaAct,
+		}
+		runAction = &work.Action{
+			Mode:       "test run",
+			Actor:      rta,
+			Deps:       []*work.Action{buildAction},
+			Package:    p,
+			IgnoreFail: true, // run (prepare output) even if build failed
+			TryCache:   rta.c.tryCache,
+		}
+		if writeCoverMetaAct != nil {
+			// If writeCoverMetaAct != nil, this indicates that our
+			// "go test -coverpkg" run actions will need to read the
+			// meta-files summary file written by writeCoverMetaAct,
+			// so add a dependence edge from writeCoverMetaAct to the
+			// run action.
+			runAction.Deps = append(runAction.Deps, writeCoverMetaAct)
+			if !p.IsTestOnly() {
+				// Package p is not test only, meaning that the build
+				// action for p may generate a static meta-data file.
+				// Add a dependence edge from p to writeCoverMetaAct,
+				// which needs to know the name of that meta-data
+				// file.
+				compileAction := b.CompileAction(work.ModeBuild, work.ModeBuild, p)
+				writeCoverMetaAct.Deps = append(writeCoverMetaAct.Deps, compileAction)
+			}
+		}
+		runAction.Objdir = testDir
+		vetRunAction = runAction
+		cleanAction = &work.Action{
+			Mode:       "test clean",
+			Actor:      work.ActorFunc(builderCleanTest),
+			Deps:       []*work.Action{runAction},
+			Package:    p,
+			IgnoreFail: true, // clean even if test failed
+			Objdir:     testDir,
+		}
+		printAction = &work.Action{
+			Mode:       "test print",
+			Actor:      work.ActorFunc(builderPrintTest),
+			Deps:       []*work.Action{cleanAction},
+			Package:    p,
+			IgnoreFail: true, // print even if test failed
+		}
+	}
+
+	if len(ptest.GoFiles)+len(ptest.CgoFiles) > 0 {
+		addTestVet(b, ptest, vetRunAction, installAction)
+	}
+	if pxtest != nil {
+		addTestVet(b, pxtest, vetRunAction, installAction)
+	}
+
+	if installAction != nil {
+		if runAction != installAction {
+			installAction.Deps = append(installAction.Deps, runAction)
+		}
+		if cleanAction != nil {
+			cleanAction.Deps = append(cleanAction.Deps, installAction)
+		}
+	}
+
+	return buildAction, runAction, printAction, nil
+}
+
+func addTestVet(b *work.Builder, p *load.Package, runAction, installAction *work.Action) {
+	if testVet.off {
+		return
+	}
+
+	vet := b.VetAction(work.ModeBuild, work.ModeBuild, p)
+	runAction.Deps = append(runAction.Deps, vet)
+	// Install will clean the build directory.
+	// Make sure vet runs first.
+	// The install ordering in b.VetAction does not apply here
+	// because we are using a custom installAction (created above).
+	if installAction != nil {
+		installAction.Deps = append(installAction.Deps, vet)
+	}
+}
+
+var noTestsToRun = []byte("\ntesting: warning: no tests to run\n")
+var noFuzzTestsToFuzz = []byte("\ntesting: warning: no fuzz tests to fuzz\n")
+var tooManyFuzzTestsToFuzz = []byte("\ntesting: warning: -fuzz matches more than one fuzz test, won't fuzz\n")
+
+// runTestActor is the actor for running a test.
+type runTestActor struct {
+	c runCache
+
+	// writeCoverMetaAct points to the pseudo-action for collecting
+	// coverage meta-data files for selected -cover test runs. See the
+	// comment in runTest at the definition of writeCoverMetaAct for
+	// more details.
+	writeCoverMetaAct *work.Action
+
+	// sequencing of json start messages, to preserve test order
+	prev <-chan struct{} // wait to start until prev is closed
+	next chan<- struct{} // close next once the next test can start.
+}
+
+// runCache is the cache for running a single test.
+type runCache struct {
+	disableCache bool // cache should be disabled for this run
+
+	buf *bytes.Buffer
+	id1 cache.ActionID
+	id2 cache.ActionID
+}
+
+// stdoutMu and lockedStdout provide a locked standard output
+// that guarantees never to interlace writes from multiple
+// goroutines, so that we can have multiple JSON streams writing
+// to a lockedStdout simultaneously and know that events will
+// still be intelligible.
+var stdoutMu sync.Mutex
+
+type lockedStdout struct{}
+
+func (lockedStdout) Write(b []byte) (int, error) {
+	stdoutMu.Lock()
+	defer stdoutMu.Unlock()
+	return os.Stdout.Write(b)
+}
+
+func (r *runTestActor) Act(b *work.Builder, ctx context.Context, a *work.Action) error {
+	sh := b.Shell(a)
+
+	// Wait for previous test to get started and print its first json line.
+	select {
+	case <-r.prev:
+	case <-base.Interrupted:
+		// We can't wait for the previous test action to complete: we don't start
+		// new actions after an interrupt, so if that action wasn't already running
+		// it might never happen. Instead, just don't log anything for this action.
+		base.SetExitStatus(1)
+		return nil
+	}
+
+	var stdout io.Writer = os.Stdout
+	var err error
+	if testJSON {
+		json := test2json.NewConverter(lockedStdout{}, a.Package.ImportPath, test2json.Timestamp)
+		defer func() {
+			json.Exited(err)
+			json.Close()
+		}()
+		stdout = json
+	}
+
+	// Release next test to start (test2json.NewConverter writes the start event).
+	close(r.next)
+
+	if a.Failed {
+		// We were unable to build the binary.
+		a.Failed = false
+		fmt.Fprintf(stdout, "FAIL\t%s [build failed]\n", a.Package.ImportPath)
+		// Tell the JSON converter that this was a failure, not a passing run.
+		err = errors.New("build failed")
+		base.SetExitStatus(1)
+		return nil
+	}
+
+	coverProfTempFile := func(a *work.Action) string {
+		if a.Objdir == "" {
+			panic("internal error: objdir not set in coverProfTempFile")
+		}
+		return a.Objdir + "_cover_.out"
+	}
+
+	if p := a.Package; len(p.TestGoFiles)+len(p.XTestGoFiles) == 0 {
+		reportNoTestFiles := true
+		if cfg.BuildCover && cfg.Experiment.CoverageRedesign {
+			if err := sh.Mkdir(a.Objdir); err != nil {
+				return err
+			}
+			mf, err := work.BuildActionCoverMetaFile(a)
+			if err != nil {
+				return err
+			} else if mf != "" {
+				reportNoTestFiles = false
+				// Write out "percent statements covered".
+				if err := work.WriteCoveragePercent(b, a, mf, stdout); err != nil {
+					return err
+				}
+				// If -coverprofile is in effect, then generate a
+				// coverage profile fragment for this package and
+				// merge it with the final -coverprofile output file.
+				if coverMerge.f != nil {
+					cp := coverProfTempFile(a)
+					if err := work.WriteCoverageProfile(b, a, mf, cp, stdout); err != nil {
+						return err
+					}
+					mergeCoverProfile(stdout, cp)
+				}
+			}
+		}
+		if reportNoTestFiles {
+			fmt.Fprintf(stdout, "?   \t%s\t[no test files]\n", p.ImportPath)
+		}
+		return nil
+	}
+
+	var buf bytes.Buffer
+	if len(pkgArgs) == 0 || testBench != "" || testFuzz != "" {
+		// Stream test output (no buffering) when no package has
+		// been given on the command line (implicit current directory)
+		// or when benchmarking or fuzzing.
+		// No change to stdout.
+	} else {
+		// If we're only running a single package under test or if parallelism is
+		// set to 1, and if we're displaying all output (testShowPass), we can
+		// hurry the output along, echoing it as soon as it comes in.
+		// We still have to copy to &buf for caching the result. This special
+		// case was introduced in Go 1.5 and is intentionally undocumented:
+		// the exact details of output buffering are up to the go command and
+		// subject to change. It would be nice to remove this special case
+		// entirely, but it is surely very helpful to see progress being made
+		// when tests are run on slow single-CPU ARM systems.
+		//
+		// If we're showing JSON output, then display output as soon as
+		// possible even when multiple tests are being run: the JSON output
+		// events are attributed to specific package tests, so interlacing them
+		// is OK.
+		if testShowPass() && (len(pkgs) == 1 || cfg.BuildP == 1) || testJSON {
+			// Write both to stdout and buf, for possible saving
+			// to cache, and for looking for the "no tests to run" message.
+			stdout = io.MultiWriter(stdout, &buf)
+		} else {
+			stdout = &buf
+		}
+	}
+
+	if r.c.buf == nil {
+		// We did not find a cached result using the link step action ID,
+		// so we ran the link step. Try again now with the link output
+		// content ID. The attempt using the action ID makes sure that
+		// if the link inputs don't change, we reuse the cached test
+		// result without even rerunning the linker. The attempt using
+		// the link output (test binary) content ID makes sure that if
+		// we have different link inputs but the same final binary,
+		// we still reuse the cached test result.
+		// c.saveOutput will store the result under both IDs.
+		r.c.tryCacheWithID(b, a, a.Deps[0].BuildContentID())
+	}
+	if r.c.buf != nil {
+		if stdout != &buf {
+			stdout.Write(r.c.buf.Bytes())
+			r.c.buf.Reset()
+		}
+		a.TestOutput = r.c.buf
+		return nil
+	}
+
+	execCmd := work.FindExecCmd()
+	testlogArg := []string{}
+	if !r.c.disableCache && len(execCmd) == 0 {
+		testlogArg = []string{"-test.testlogfile=" + a.Objdir + "testlog.txt"}
+	}
+	panicArg := "-test.paniconexit0"
+	fuzzArg := []string{}
+	if testFuzz != "" {
+		fuzzCacheDir := filepath.Join(cache.Default().FuzzDir(), a.Package.ImportPath)
+		fuzzArg = []string{"-test.fuzzcachedir=" + fuzzCacheDir}
+	}
+	coverdirArg := []string{}
+	addToEnv := ""
+	if cfg.BuildCover {
+		gcd := filepath.Join(a.Objdir, "gocoverdir")
+		if err := sh.Mkdir(gcd); err != nil {
+			// If we can't create a temp dir, terminate immediately
+			// with an error as opposed to returning an error to the
+			// caller; failed MkDir most likely indicates that we're
+			// out of disk space or there is some other systemic error
+			// that will make forward progress unlikely.
+			base.Fatalf("failed to create temporary dir: %v", err)
+		}
+		coverdirArg = append(coverdirArg, "-test.gocoverdir="+gcd)
+		if r.writeCoverMetaAct != nil {
+			// Copy the meta-files file over into the test's coverdir
+			// directory so that the coverage runtime support will be
+			// able to find it.
+			src := r.writeCoverMetaAct.Objdir + coverage.MetaFilesFileName
+			dst := filepath.Join(gcd, coverage.MetaFilesFileName)
+			if err := sh.CopyFile(dst, src, 0666, false); err != nil {
+				return err
+			}
+		}
+		// Even though we are passing the -test.gocoverdir option to
+		// the test binary, also set GOCOVERDIR as well. This is
+		// intended to help with tests that run "go build" to build
+		// fresh copies of tools to test as part of the testing.
+		addToEnv = "GOCOVERDIR=" + gcd
+	}
+	args := str.StringList(execCmd, a.Deps[0].BuiltTarget(), testlogArg, panicArg, fuzzArg, coverdirArg, testArgs)
+
+	if testCoverProfile != "" {
+		// Write coverage to temporary profile, for merging later.
+		for i, arg := range args {
+			if strings.HasPrefix(arg, "-test.coverprofile=") {
+				args[i] = "-test.coverprofile=" + coverProfTempFile(a)
+			}
+		}
+	}
+
+	if cfg.BuildN || cfg.BuildX {
+		sh.ShowCmd("", "%s", strings.Join(args, " "))
+		if cfg.BuildN {
+			return nil
+		}
+	}
+
+	// Normally, the test will terminate itself when the timeout expires,
+	// but add a last-ditch deadline to detect and stop wedged binaries.
+	ctx, cancel := context.WithTimeout(ctx, testKillTimeout)
+	defer cancel()
+
+	// Now we're ready to actually run the command.
+	//
+	// If the -o flag is set, or if at some point we change cmd/go to start
+	// copying test executables into the build cache, we may run into spurious
+	// ETXTBSY errors on Unix platforms (see https://go.dev/issue/22315).
+	//
+	// Since we know what causes those, and we know that they should resolve
+	// quickly (the ETXTBSY error will resolve as soon as the subprocess
+	// holding the descriptor open reaches its 'exec' call), we retry them
+	// in a loop.
+
+	var (
+		cmd            *exec.Cmd
+		t0             time.Time
+		cancelKilled   = false
+		cancelSignaled = false
+	)
+	for {
+		cmd = exec.CommandContext(ctx, args[0], args[1:]...)
+		cmd.Dir = a.Package.Dir
+
+		env := slices.Clip(cfg.OrigEnv)
+		env = base.AppendPATH(env)
+		env = base.AppendPWD(env, cmd.Dir)
+		cmd.Env = env
+		if addToEnv != "" {
+			cmd.Env = append(cmd.Env, addToEnv)
+		}
+
+		cmd.Stdout = stdout
+		cmd.Stderr = stdout
+
+		cmd.Cancel = func() error {
+			if base.SignalTrace == nil {
+				err := cmd.Process.Kill()
+				if err == nil {
+					cancelKilled = true
+				}
+				return err
+			}
+
+			// Send a quit signal in the hope that the program will print
+			// a stack trace and exit.
+			err := cmd.Process.Signal(base.SignalTrace)
+			if err == nil {
+				cancelSignaled = true
+			}
+			return err
+		}
+		cmd.WaitDelay = testWaitDelay
+
+		base.StartSigHandlers()
+		t0 = time.Now()
+		err = cmd.Run()
+
+		if !isETXTBSY(err) {
+			// We didn't hit the race in #22315, so there is no reason to retry the
+			// command.
+			break
+		}
+	}
+
+	out := buf.Bytes()
+	a.TestOutput = &buf
+	t := fmt.Sprintf("%.3fs", time.Since(t0).Seconds())
+
+	mergeCoverProfile(cmd.Stdout, a.Objdir+"_cover_.out")
+
+	if err == nil {
+		norun := ""
+		if !testShowPass() && !testJSON {
+			buf.Reset()
+		}
+		if bytes.HasPrefix(out, noTestsToRun[1:]) || bytes.Contains(out, noTestsToRun) {
+			norun = " [no tests to run]"
+		}
+		if bytes.HasPrefix(out, noFuzzTestsToFuzz[1:]) || bytes.Contains(out, noFuzzTestsToFuzz) {
+			norun = " [no fuzz tests to fuzz]"
+		}
+		if bytes.HasPrefix(out, tooManyFuzzTestsToFuzz[1:]) || bytes.Contains(out, tooManyFuzzTestsToFuzz) {
+			norun = "[-fuzz matches more than one fuzz test, won't fuzz]"
+		}
+		if len(out) > 0 && !bytes.HasSuffix(out, []byte("\n")) {
+			// Ensure that the output ends with a newline before the "ok"
+			// line we're about to print (https://golang.org/issue/49317).
+			cmd.Stdout.Write([]byte("\n"))
+		}
+		fmt.Fprintf(cmd.Stdout, "ok  \t%s\t%s%s%s\n", a.Package.ImportPath, t, coveragePercentage(out), norun)
+		r.c.saveOutput(a)
+	} else {
+		base.SetExitStatus(1)
+		if cancelSignaled {
+			fmt.Fprintf(cmd.Stdout, "*** Test killed with %v: ran too long (%v).\n", base.SignalTrace, testKillTimeout)
+		} else if cancelKilled {
+			fmt.Fprintf(cmd.Stdout, "*** Test killed: ran too long (%v).\n", testKillTimeout)
+		} else if errors.Is(err, exec.ErrWaitDelay) {
+			fmt.Fprintf(cmd.Stdout, "*** Test I/O incomplete %v after exiting.\n", cmd.WaitDelay)
+		}
+		var ee *exec.ExitError
+		if len(out) == 0 || !errors.As(err, &ee) || !ee.Exited() {
+			// If there was no test output, print the exit status so that the reason
+			// for failure is clear.
+			fmt.Fprintf(cmd.Stdout, "%s\n", err)
+		} else if !bytes.HasSuffix(out, []byte("\n")) {
+			// Otherwise, ensure that the output ends with a newline before the FAIL
+			// line we're about to print (https://golang.org/issue/49317).
+			cmd.Stdout.Write([]byte("\n"))
+		}
+
+		// NOTE(golang.org/issue/37555): test2json reports that a test passes
+		// unless "FAIL" is printed at the beginning of a line. The test may not
+		// actually print that if it panics, exits, or terminates abnormally,
+		// so we print it here. We can't always check whether it was printed
+		// because some tests need stdout to be a terminal (golang.org/issue/34791),
+		// not a pipe.
+		// TODO(golang.org/issue/29062): tests that exit with status 0 without
+		// printing a final result should fail.
+		prefix := ""
+		if testJSON || testV.json {
+			prefix = "\x16"
+		}
+		fmt.Fprintf(cmd.Stdout, "%sFAIL\t%s\t%s\n", prefix, a.Package.ImportPath, t)
+	}
+
+	if cmd.Stdout != &buf {
+		buf.Reset() // cmd.Stdout was going to os.Stdout already
+	}
+	return nil
+}
+
+// tryCache is called just before the link attempt,
+// to see if the test result is cached and therefore the link is unneeded.
+// It reports whether the result can be satisfied from cache.
+func (c *runCache) tryCache(b *work.Builder, a *work.Action) bool {
+	return c.tryCacheWithID(b, a, a.Deps[0].BuildActionID())
+}
+
+func (c *runCache) tryCacheWithID(b *work.Builder, a *work.Action, id string) bool {
+	if len(pkgArgs) == 0 {
+		// Caching does not apply to "go test",
+		// only to "go test foo" (including "go test .").
+		if cache.DebugTest {
+			fmt.Fprintf(os.Stderr, "testcache: caching disabled in local directory mode\n")
+		}
+		c.disableCache = true
+		return false
+	}
+
+	if a.Package.Root == "" {
+		// Caching does not apply to tests outside of any module, GOPATH, or GOROOT.
+		if cache.DebugTest {
+			fmt.Fprintf(os.Stderr, "testcache: caching disabled for package outside of module root, GOPATH, or GOROOT: %s\n", a.Package.ImportPath)
+		}
+		c.disableCache = true
+		return false
+	}
+
+	var cacheArgs []string
+	for _, arg := range testArgs {
+		i := strings.Index(arg, "=")
+		if i < 0 || !strings.HasPrefix(arg, "-test.") {
+			if cache.DebugTest {
+				fmt.Fprintf(os.Stderr, "testcache: caching disabled for test argument: %s\n", arg)
+			}
+			c.disableCache = true
+			return false
+		}
+		switch arg[:i] {
+		case "-test.benchtime",
+			"-test.cpu",
+			"-test.list",
+			"-test.parallel",
+			"-test.run",
+			"-test.short",
+			"-test.timeout",
+			"-test.failfast",
+			"-test.v":
+			// These are cacheable.
+			// Note that this list is documented above,
+			// so if you add to this list, update the docs too.
+			cacheArgs = append(cacheArgs, arg)
+
+		default:
+			// nothing else is cacheable
+			if cache.DebugTest {
+				fmt.Fprintf(os.Stderr, "testcache: caching disabled for test argument: %s\n", arg)
+			}
+			c.disableCache = true
+			return false
+		}
+	}
+
+	// The test cache result fetch is a two-level lookup.
+	//
+	// First, we use the content hash of the test binary
+	// and its command-line arguments to find the
+	// list of environment variables and files consulted
+	// the last time the test was run with those arguments.
+	// (To avoid unnecessary links, we store this entry
+	// under two hashes: id1 uses the linker inputs as a
+	// proxy for the test binary, and id2 uses the actual
+	// test binary. If the linker inputs are unchanged,
+	// this way we avoid the link step, even though we
+	// do not cache link outputs.)
+	//
+	// Second, we compute a hash of the values of the
+	// environment variables and the content of the files
+	// listed in the log from the previous run.
+	// Then we look up test output using a combination of
+	// the hash from the first part (testID) and the hash of the
+	// test inputs (testInputsID).
+	//
+	// In order to store a new test result, we must redo the
+	// testInputsID computation using the log from the run
+	// we want to cache, and then we store that new log and
+	// the new outputs.
+
+	h := cache.NewHash("testResult")
+	fmt.Fprintf(h, "test binary %s args %q execcmd %q", id, cacheArgs, work.ExecCmd)
+	testID := h.Sum()
+	if c.id1 == (cache.ActionID{}) {
+		c.id1 = testID
+	} else {
+		c.id2 = testID
+	}
+	if cache.DebugTest {
+		fmt.Fprintf(os.Stderr, "testcache: %s: test ID %x => %x\n", a.Package.ImportPath, id, testID)
+	}
+
+	// Load list of referenced environment variables and files
+	// from last run of testID, and compute hash of that content.
+	data, entry, err := cache.GetBytes(cache.Default(), testID)
+	if !bytes.HasPrefix(data, testlogMagic) || data[len(data)-1] != '\n' {
+		if cache.DebugTest {
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "testcache: %s: input list not found: %v\n", a.Package.ImportPath, err)
+			} else {
+				fmt.Fprintf(os.Stderr, "testcache: %s: input list malformed\n", a.Package.ImportPath)
+			}
+		}
+		return false
+	}
+	testInputsID, err := computeTestInputsID(a, data)
+	if err != nil {
+		return false
+	}
+	if cache.DebugTest {
+		fmt.Fprintf(os.Stderr, "testcache: %s: test ID %x => input ID %x => %x\n", a.Package.ImportPath, testID, testInputsID, testAndInputKey(testID, testInputsID))
+	}
+
+	// Parse cached result in preparation for changing run time to "(cached)".
+	// If we can't parse the cached result, don't use it.
+	data, entry, err = cache.GetBytes(cache.Default(), testAndInputKey(testID, testInputsID))
+	if len(data) == 0 || data[len(data)-1] != '\n' {
+		if cache.DebugTest {
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "testcache: %s: test output not found: %v\n", a.Package.ImportPath, err)
+			} else {
+				fmt.Fprintf(os.Stderr, "testcache: %s: test output malformed\n", a.Package.ImportPath)
+			}
+		}
+		return false
+	}
+	if entry.Time.Before(testCacheExpire) {
+		if cache.DebugTest {
+			fmt.Fprintf(os.Stderr, "testcache: %s: test output expired due to go clean -testcache\n", a.Package.ImportPath)
+		}
+		return false
+	}
+	i := bytes.LastIndexByte(data[:len(data)-1], '\n') + 1
+	if !bytes.HasPrefix(data[i:], []byte("ok  \t")) {
+		if cache.DebugTest {
+			fmt.Fprintf(os.Stderr, "testcache: %s: test output malformed\n", a.Package.ImportPath)
+		}
+		return false
+	}
+	j := bytes.IndexByte(data[i+len("ok  \t"):], '\t')
+	if j < 0 {
+		if cache.DebugTest {
+			fmt.Fprintf(os.Stderr, "testcache: %s: test output malformed\n", a.Package.ImportPath)
+		}
+		return false
+	}
+	j += i + len("ok  \t") + 1
+
+	// Committed to printing.
+	c.buf = new(bytes.Buffer)
+	c.buf.Write(data[:j])
+	c.buf.WriteString("(cached)")
+	for j < len(data) && ('0' <= data[j] && data[j] <= '9' || data[j] == '.' || data[j] == 's') {
+		j++
+	}
+	c.buf.Write(data[j:])
+	return true
+}
+
+var errBadTestInputs = errors.New("error parsing test inputs")
+var testlogMagic = []byte("# test log\n") // known to testing/internal/testdeps/deps.go
+
+// computeTestInputsID computes the "test inputs ID"
+// (see comment in tryCacheWithID above) for the
+// test log.
+func computeTestInputsID(a *work.Action, testlog []byte) (cache.ActionID, error) {
+	testlog = bytes.TrimPrefix(testlog, testlogMagic)
+	h := cache.NewHash("testInputs")
+	pwd := a.Package.Dir
+	for _, line := range bytes.Split(testlog, []byte("\n")) {
+		if len(line) == 0 {
+			continue
+		}
+		s := string(line)
+		op, name, found := strings.Cut(s, " ")
+		if !found {
+			if cache.DebugTest {
+				fmt.Fprintf(os.Stderr, "testcache: %s: input list malformed (%q)\n", a.Package.ImportPath, line)
+			}
+			return cache.ActionID{}, errBadTestInputs
+		}
+		switch op {
+		default:
+			if cache.DebugTest {
+				fmt.Fprintf(os.Stderr, "testcache: %s: input list malformed (%q)\n", a.Package.ImportPath, line)
+			}
+			return cache.ActionID{}, errBadTestInputs
+		case "getenv":
+			fmt.Fprintf(h, "env %s %x\n", name, hashGetenv(name))
+		case "chdir":
+			pwd = name // always absolute
+			fmt.Fprintf(h, "chdir %s %x\n", name, hashStat(name))
+		case "stat":
+			if !filepath.IsAbs(name) {
+				name = filepath.Join(pwd, name)
+			}
+			if a.Package.Root == "" || search.InDir(name, a.Package.Root) == "" {
+				// Do not recheck files outside the module, GOPATH, or GOROOT root.
+				break
+			}
+			fmt.Fprintf(h, "stat %s %x\n", name, hashStat(name))
+		case "open":
+			if !filepath.IsAbs(name) {
+				name = filepath.Join(pwd, name)
+			}
+			if a.Package.Root == "" || search.InDir(name, a.Package.Root) == "" {
+				// Do not recheck files outside the module, GOPATH, or GOROOT root.
+				break
+			}
+			fh, err := hashOpen(name)
+			if err != nil {
+				if cache.DebugTest {
+					fmt.Fprintf(os.Stderr, "testcache: %s: input file %s: %s\n", a.Package.ImportPath, name, err)
+				}
+				return cache.ActionID{}, err
+			}
+			fmt.Fprintf(h, "open %s %x\n", name, fh)
+		}
+	}
+	sum := h.Sum()
+	return sum, nil
+}
+
+func hashGetenv(name string) cache.ActionID {
+	h := cache.NewHash("getenv")
+	v, ok := os.LookupEnv(name)
+	if !ok {
+		h.Write([]byte{0})
+	} else {
+		h.Write([]byte{1})
+		h.Write([]byte(v))
+	}
+	return h.Sum()
+}
+
+const modTimeCutoff = 2 * time.Second
+
+var errFileTooNew = errors.New("file used as input is too new")
+
+func hashOpen(name string) (cache.ActionID, error) {
+	h := cache.NewHash("open")
+	info, err := os.Stat(name)
+	if err != nil {
+		fmt.Fprintf(h, "err %v\n", err)
+		return h.Sum(), nil
+	}
+	hashWriteStat(h, info)
+	if info.IsDir() {
+		files, err := os.ReadDir(name)
+		if err != nil {
+			fmt.Fprintf(h, "err %v\n", err)
+		}
+		for _, f := range files {
+			fmt.Fprintf(h, "file %s ", f.Name())
+			finfo, err := f.Info()
+			if err != nil {
+				fmt.Fprintf(h, "err %v\n", err)
+			} else {
+				hashWriteStat(h, finfo)
+			}
+		}
+	} else if info.Mode().IsRegular() {
+		// Because files might be very large, do not attempt
+		// to hash the entirety of their content. Instead assume
+		// the mtime and size recorded in hashWriteStat above
+		// are good enough.
+		//
+		// To avoid problems for very recent files where a new
+		// write might not change the mtime due to file system
+		// mtime precision, reject caching if a file was read that
+		// is less than modTimeCutoff old.
+		if time.Since(info.ModTime()) < modTimeCutoff {
+			return cache.ActionID{}, errFileTooNew
+		}
+	}
+	return h.Sum(), nil
+}
+
+func hashStat(name string) cache.ActionID {
+	h := cache.NewHash("stat")
+	if info, err := os.Stat(name); err != nil {
+		fmt.Fprintf(h, "err %v\n", err)
+	} else {
+		hashWriteStat(h, info)
+	}
+	if info, err := os.Lstat(name); err != nil {
+		fmt.Fprintf(h, "err %v\n", err)
+	} else {
+		hashWriteStat(h, info)
+	}
+	return h.Sum()
+}
+
+func hashWriteStat(h io.Writer, info fs.FileInfo) {
+	fmt.Fprintf(h, "stat %d %x %v %v\n", info.Size(), uint64(info.Mode()), info.ModTime(), info.IsDir())
+}
+
+// testAndInputKey returns the actual cache key for the pair (testID, testInputsID).
+func testAndInputKey(testID, testInputsID cache.ActionID) cache.ActionID {
+	return cache.Subkey(testID, fmt.Sprintf("inputs:%x", testInputsID))
+}
+
+func (c *runCache) saveOutput(a *work.Action) {
+	if c.id1 == (cache.ActionID{}) && c.id2 == (cache.ActionID{}) {
+		return
+	}
+
+	// See comment about two-level lookup in tryCacheWithID above.
+	testlog, err := os.ReadFile(a.Objdir + "testlog.txt")
+	if err != nil || !bytes.HasPrefix(testlog, testlogMagic) || testlog[len(testlog)-1] != '\n' {
+		if cache.DebugTest {
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "testcache: %s: reading testlog: %v\n", a.Package.ImportPath, err)
+			} else {
+				fmt.Fprintf(os.Stderr, "testcache: %s: reading testlog: malformed\n", a.Package.ImportPath)
+			}
+		}
+		return
+	}
+	testInputsID, err := computeTestInputsID(a, testlog)
+	if err != nil {
+		return
+	}
+	if c.id1 != (cache.ActionID{}) {
+		if cache.DebugTest {
+			fmt.Fprintf(os.Stderr, "testcache: %s: save test ID %x => input ID %x => %x\n", a.Package.ImportPath, c.id1, testInputsID, testAndInputKey(c.id1, testInputsID))
+		}
+		cache.PutNoVerify(cache.Default(), c.id1, bytes.NewReader(testlog))
+		cache.PutNoVerify(cache.Default(), testAndInputKey(c.id1, testInputsID), bytes.NewReader(a.TestOutput.Bytes()))
+	}
+	if c.id2 != (cache.ActionID{}) {
+		if cache.DebugTest {
+			fmt.Fprintf(os.Stderr, "testcache: %s: save test ID %x => input ID %x => %x\n", a.Package.ImportPath, c.id2, testInputsID, testAndInputKey(c.id2, testInputsID))
+		}
+		cache.PutNoVerify(cache.Default(), c.id2, bytes.NewReader(testlog))
+		cache.PutNoVerify(cache.Default(), testAndInputKey(c.id2, testInputsID), bytes.NewReader(a.TestOutput.Bytes()))
+	}
+}
+
+// coveragePercentage returns the coverage results (if enabled) for the
+// test. It uncovers the data by scanning the output from the test run.
+func coveragePercentage(out []byte) string {
+	if !cfg.BuildCover {
+		return ""
+	}
+	// The string looks like
+	//	test coverage for encoding/binary: 79.9% of statements
+	// Extract the piece from the percentage to the end of the line.
+	re := regexp.MustCompile(`coverage: (.*)\n`)
+	matches := re.FindSubmatch(out)
+	if matches == nil {
+		// Probably running "go test -cover" not "go test -cover fmt".
+		// The coverage output will appear in the output directly.
+		return ""
+	}
+	return fmt.Sprintf("\tcoverage: %s", matches[1])
+}
+
+// builderCleanTest is the action for cleaning up after a test.
+func builderCleanTest(b *work.Builder, ctx context.Context, a *work.Action) error {
+	if cfg.BuildWork {
+		return nil
+	}
+	b.Shell(a).RemoveAll(a.Objdir)
+	return nil
+}
+
+// builderPrintTest is the action for printing a test result.
+func builderPrintTest(b *work.Builder, ctx context.Context, a *work.Action) error {
+	clean := a.Deps[0]
+	run := clean.Deps[0]
+	if run.TestOutput != nil {
+		os.Stdout.Write(run.TestOutput.Bytes())
+		run.TestOutput = nil
+	}
+	return nil
+}
+
+// printExitStatus is the action for printing the final exit status.
+// If we are running multiple test targets, print a final "FAIL"
+// in case a failure in an early package has already scrolled
+// off of the user's terminal.
+// (See https://golang.org/issue/30507#issuecomment-470593235.)
+//
+// In JSON mode, we need to maintain valid JSON output and
+// we assume that the test output is being parsed by a tool
+// anyway, so the failure will not be missed and would be
+// awkward to try to wedge into the JSON stream.
+//
+// In fuzz mode, we only allow a single package for now
+// (see CL 350156 and https://golang.org/issue/46312),
+// so there is no possibility of scrolling off and no need
+// to print the final status.
+func printExitStatus(b *work.Builder, ctx context.Context, a *work.Action) error {
+	if !testJSON && testFuzz == "" && len(pkgArgs) != 0 {
+		if base.GetExitStatus() != 0 {
+			fmt.Println("FAIL")
+			return nil
+		}
+	}
+	return nil
+}
+
+// testBinaryName can be used to create name for test binary executable.
+// Use last element of import path, not package name.
+// They differ when package name is "main".
+// But if the import path is "command-line-arguments",
+// like it is during 'go run', use the package name.
+func testBinaryName(p *load.Package) string {
+	var elem string
+	if p.ImportPath == "command-line-arguments" {
+		elem = p.Name
+	} else {
+		elem = p.DefaultExecName()
+	}
+
+	return elem + ".test"
+}
diff --git a/src/cmd/go/internal/test/test_nonunix.go b/src/cmd/go/internal/test/test_nonunix.go
new file mode 100644
index 0000000..df84487
--- /dev/null
+++ b/src/cmd/go/internal/test/test_nonunix.go
@@ -0,0 +1,12 @@
+// Copyright 2023 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.
+
+//go:build !unix
+
+package test
+
+func isETXTBSY(err error) bool {
+	// syscall.ETXTBSY is only meaningful on Unix platforms.
+	return false
+}
diff --git a/src/cmd/go/internal/test/test_unix.go b/src/cmd/go/internal/test/test_unix.go
new file mode 100644
index 0000000..f50ef98
--- /dev/null
+++ b/src/cmd/go/internal/test/test_unix.go
@@ -0,0 +1,16 @@
+// Copyright 2023 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.
+
+//go:build unix
+
+package test
+
+import (
+	"errors"
+	"syscall"
+)
+
+func isETXTBSY(err error) bool {
+	return errors.Is(err, syscall.ETXTBSY)
+}
diff --git a/src/cmd/go/internal/test/testflag.go b/src/cmd/go/internal/test/testflag.go
new file mode 100644
index 0000000..4253788
--- /dev/null
+++ b/src/cmd/go/internal/test/testflag.go
@@ -0,0 +1,416 @@
+// Copyright 2011 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 test
+
+import (
+	"cmd/go/internal/base"
+	"cmd/go/internal/cmdflag"
+	"cmd/go/internal/work"
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+)
+
+//go:generate go run ./genflags.go
+
+// The flag handling part of go test is large and distracting.
+// We can't use (*flag.FlagSet).Parse because some of the flags from
+// our command line are for us, and some are for the test binary, and
+// some are for both.
+
+func init() {
+	work.AddBuildFlags(CmdTest, work.OmitVFlag)
+
+	cf := CmdTest.Flag
+	cf.BoolVar(&testC, "c", false, "")
+	cf.StringVar(&testO, "o", "", "")
+	work.AddCoverFlags(CmdTest, &testCoverProfile)
+	cf.Var((*base.StringsFlag)(&work.ExecCmd), "exec", "")
+	cf.BoolVar(&testJSON, "json", false, "")
+	cf.Var(&testVet, "vet", "")
+
+	// Register flags to be forwarded to the test binary. We retain variables for
+	// some of them so that cmd/go knows what to do with the test output, or knows
+	// to build the test in a way that supports the use of the flag.
+
+	cf.StringVar(&testBench, "bench", "", "")
+	cf.Bool("benchmem", false, "")
+	cf.String("benchtime", "", "")
+	cf.StringVar(&testBlockProfile, "blockprofile", "", "")
+	cf.String("blockprofilerate", "", "")
+	cf.Int("count", 0, "")
+	cf.String("cpu", "", "")
+	cf.StringVar(&testCPUProfile, "cpuprofile", "", "")
+	cf.Bool("failfast", false, "")
+	cf.StringVar(&testFuzz, "fuzz", "", "")
+	cf.Bool("fullpath", false, "")
+	cf.StringVar(&testList, "list", "", "")
+	cf.StringVar(&testMemProfile, "memprofile", "", "")
+	cf.String("memprofilerate", "", "")
+	cf.StringVar(&testMutexProfile, "mutexprofile", "", "")
+	cf.String("mutexprofilefraction", "", "")
+	cf.Var(&testOutputDir, "outputdir", "")
+	cf.Int("parallel", 0, "")
+	cf.String("run", "", "")
+	cf.Bool("short", false, "")
+	cf.String("skip", "", "")
+	cf.DurationVar(&testTimeout, "timeout", 10*time.Minute, "") // known to cmd/dist
+	cf.String("fuzztime", "", "")
+	cf.String("fuzzminimizetime", "", "")
+	cf.StringVar(&testTrace, "trace", "", "")
+	cf.Var(&testV, "v", "")
+	cf.Var(&testShuffle, "shuffle", "")
+
+	for name, ok := range passFlagToTest {
+		if ok {
+			cf.Var(cf.Lookup(name).Value, "test."+name, "")
+		}
+	}
+}
+
+// outputdirFlag implements the -outputdir flag.
+// It interprets an empty value as the working directory of the 'go' command.
+type outputdirFlag struct {
+	abs string
+}
+
+func (f *outputdirFlag) String() string {
+	return f.abs
+}
+
+func (f *outputdirFlag) Set(value string) (err error) {
+	if value == "" {
+		f.abs = ""
+	} else {
+		f.abs, err = filepath.Abs(value)
+	}
+	return err
+}
+
+func (f *outputdirFlag) getAbs() string {
+	if f.abs == "" {
+		return base.Cwd()
+	}
+	return f.abs
+}
+
+// vetFlag implements the special parsing logic for the -vet flag:
+// a comma-separated list, with distinguished values "all" and
+// "off", plus a boolean tracking whether it was set explicitly.
+//
+// "all" is encoded as vetFlag{true, false, nil}, since it will
+// pass no flags to the vet binary, and by default, it runs all
+// analyzers.
+type vetFlag struct {
+	explicit bool
+	off      bool
+	flags    []string // passed to vet when invoked automatically during 'go test'
+}
+
+func (f *vetFlag) String() string {
+	switch {
+	case !f.off && !f.explicit && len(f.flags) == 0:
+		return "all"
+	case f.off:
+		return "off"
+	}
+
+	var buf strings.Builder
+	for i, f := range f.flags {
+		if i > 0 {
+			buf.WriteByte(',')
+		}
+		buf.WriteString(f)
+	}
+	return buf.String()
+}
+
+func (f *vetFlag) Set(value string) error {
+	switch {
+	case value == "":
+		*f = vetFlag{flags: defaultVetFlags}
+		return nil
+	case strings.Contains(value, "="):
+		return fmt.Errorf("-vet argument cannot contain equal signs")
+	case strings.Contains(value, " "):
+		return fmt.Errorf("-vet argument is comma-separated list, cannot contain spaces")
+	}
+
+	*f = vetFlag{explicit: true}
+	var single string
+	for _, arg := range strings.Split(value, ",") {
+		switch arg {
+		case "":
+			return fmt.Errorf("-vet argument contains empty list element")
+		case "all":
+			single = arg
+			*f = vetFlag{explicit: true}
+			continue
+		case "off":
+			single = arg
+			*f = vetFlag{
+				explicit: true,
+				off:      true,
+			}
+			continue
+		default:
+			if _, ok := passAnalyzersToVet[arg]; !ok {
+				return fmt.Errorf("-vet argument must be a supported analyzer or a distinguished value; found %s", arg)
+			}
+			f.flags = append(f.flags, "-"+arg)
+		}
+	}
+	if len(f.flags) > 1 && single != "" {
+		return fmt.Errorf("-vet does not accept %q in a list with other analyzers", single)
+	}
+	if len(f.flags) > 1 && single != "" {
+		return fmt.Errorf("-vet does not accept %q in a list with other analyzers", single)
+	}
+	return nil
+}
+
+type shuffleFlag struct {
+	on   bool
+	seed *int64
+}
+
+func (f *shuffleFlag) String() string {
+	if !f.on {
+		return "off"
+	}
+	if f.seed == nil {
+		return "on"
+	}
+	return fmt.Sprintf("%d", *f.seed)
+}
+
+func (f *shuffleFlag) Set(value string) error {
+	if value == "off" {
+		*f = shuffleFlag{on: false}
+		return nil
+	}
+
+	if value == "on" {
+		*f = shuffleFlag{on: true}
+		return nil
+	}
+
+	seed, err := strconv.ParseInt(value, 10, 64)
+	if err != nil {
+		return fmt.Errorf(`-shuffle argument must be "on", "off", or an int64: %v`, err)
+	}
+
+	*f = shuffleFlag{on: true, seed: &seed}
+	return nil
+}
+
+// testFlags processes the command line, grabbing -x and -c, rewriting known flags
+// to have "test" before them, and reading the command line for the test binary.
+// Unfortunately for us, we need to do our own flag processing because go test
+// grabs some flags but otherwise its command line is just a holding place for
+// pkg.test's arguments.
+// We allow known flags both before and after the package name list,
+// to allow both
+//
+//	go test fmt -custom-flag-for-fmt-test
+//	go test -x math
+func testFlags(args []string) (packageNames, passToTest []string) {
+	base.SetFromGOFLAGS(&CmdTest.Flag)
+	addFromGOFLAGS := map[string]bool{}
+	CmdTest.Flag.Visit(func(f *flag.Flag) {
+		if short := strings.TrimPrefix(f.Name, "test."); passFlagToTest[short] {
+			addFromGOFLAGS[f.Name] = true
+		}
+	})
+
+	// firstUnknownFlag helps us report an error when flags not known to 'go
+	// test' are used along with -i or -c.
+	firstUnknownFlag := ""
+
+	explicitArgs := make([]string, 0, len(args))
+	inPkgList := false
+	afterFlagWithoutValue := false
+	for len(args) > 0 {
+		f, remainingArgs, err := cmdflag.ParseOne(&CmdTest.Flag, args)
+
+		wasAfterFlagWithoutValue := afterFlagWithoutValue
+		afterFlagWithoutValue = false // provisionally
+
+		if errors.Is(err, flag.ErrHelp) {
+			exitWithUsage()
+		}
+
+		if errors.Is(err, cmdflag.ErrFlagTerminator) {
+			// 'go list' allows package arguments to be named either before or after
+			// the terminator, but 'go test' has historically allowed them only
+			// before. Preserve that behavior and treat all remaining arguments —
+			// including the terminator itself! — as arguments to the test.
+			explicitArgs = append(explicitArgs, args...)
+			break
+		}
+
+		if nf := (cmdflag.NonFlagError{}); errors.As(err, &nf) {
+			if !inPkgList && packageNames != nil {
+				// We already saw the package list previously, and this argument is not
+				// a flag, so it — and everything after it — must be either a value for
+				// a preceding flag or a literal argument to the test binary.
+				if wasAfterFlagWithoutValue {
+					// This argument could syntactically be a flag value, so
+					// optimistically assume that it is and keep looking for go command
+					// flags after it.
+					//
+					// (If we're wrong, we'll at least be consistent with historical
+					// behavior; see https://golang.org/issue/40763.)
+					explicitArgs = append(explicitArgs, nf.RawArg)
+					args = remainingArgs
+					continue
+				} else {
+					// This argument syntactically cannot be a flag value, so it must be a
+					// positional argument, and so must everything after it.
+					explicitArgs = append(explicitArgs, args...)
+					break
+				}
+			}
+
+			inPkgList = true
+			packageNames = append(packageNames, nf.RawArg)
+			args = remainingArgs // Consume the package name.
+			continue
+		}
+
+		if inPkgList {
+			// This argument is syntactically a flag, so if we were in the package
+			// list we're not anymore.
+			inPkgList = false
+		}
+
+		if nd := (cmdflag.FlagNotDefinedError{}); errors.As(err, &nd) {
+			// This is a flag we do not know. We must assume that any args we see
+			// after this might be flag arguments, not package names, so make
+			// packageNames non-nil to indicate that the package list is complete.
+			//
+			// (Actually, we only strictly need to assume that if the flag is not of
+			// the form -x=value, but making this more precise would be a breaking
+			// change in the command line API.)
+			if packageNames == nil {
+				packageNames = []string{}
+			}
+
+			if nd.RawArg == "-args" || nd.RawArg == "--args" {
+				// -args or --args signals that everything that follows
+				// should be passed to the test.
+				explicitArgs = append(explicitArgs, remainingArgs...)
+				break
+			}
+
+			if firstUnknownFlag == "" {
+				firstUnknownFlag = nd.RawArg
+			}
+
+			explicitArgs = append(explicitArgs, nd.RawArg)
+			args = remainingArgs
+			if !nd.HasValue {
+				afterFlagWithoutValue = true
+			}
+			continue
+		}
+
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			exitWithUsage()
+		}
+
+		if short := strings.TrimPrefix(f.Name, "test."); passFlagToTest[short] {
+			explicitArgs = append(explicitArgs, fmt.Sprintf("-test.%s=%v", short, f.Value))
+
+			// This flag has been overridden explicitly, so don't forward its implicit
+			// value from GOFLAGS.
+			delete(addFromGOFLAGS, short)
+			delete(addFromGOFLAGS, "test."+short)
+		}
+
+		args = remainingArgs
+	}
+	if firstUnknownFlag != "" && testC {
+		fmt.Fprintf(os.Stderr, "go: unknown flag %s cannot be used with -c\n", firstUnknownFlag)
+		exitWithUsage()
+	}
+
+	var injectedFlags []string
+	if testJSON {
+		// If converting to JSON, we need the full output in order to pipe it to test2json.
+		// The -test.v=test2json flag is like -test.v=true but causes the test to add
+		// extra ^V characters before testing output lines and other framing,
+		// which helps test2json do a better job creating the JSON events.
+		injectedFlags = append(injectedFlags, "-test.v=test2json")
+		delete(addFromGOFLAGS, "v")
+		delete(addFromGOFLAGS, "test.v")
+	}
+
+	// Inject flags from GOFLAGS before the explicit command-line arguments.
+	// (They must appear before the flag terminator or first non-flag argument.)
+	// Also determine whether flags with awkward defaults have already been set.
+	var timeoutSet, outputDirSet bool
+	CmdTest.Flag.Visit(func(f *flag.Flag) {
+		short := strings.TrimPrefix(f.Name, "test.")
+		if addFromGOFLAGS[f.Name] {
+			injectedFlags = append(injectedFlags, fmt.Sprintf("-test.%s=%v", short, f.Value))
+		}
+		switch short {
+		case "timeout":
+			timeoutSet = true
+		case "outputdir":
+			outputDirSet = true
+		}
+	})
+
+	// 'go test' has a default timeout, but the test binary itself does not.
+	// If the timeout wasn't set (and forwarded) explicitly, add the default
+	// timeout to the command line.
+	if testTimeout > 0 && !timeoutSet {
+		injectedFlags = append(injectedFlags, fmt.Sprintf("-test.timeout=%v", testTimeout))
+	}
+
+	// Similarly, the test binary defaults -test.outputdir to its own working
+	// directory, but 'go test' defaults it to the working directory of the 'go'
+	// command. Set it explicitly if it is needed due to some other flag that
+	// requests output.
+	if testProfile() != "" && !outputDirSet {
+		injectedFlags = append(injectedFlags, "-test.outputdir="+testOutputDir.getAbs())
+	}
+
+	// If the user is explicitly passing -help or -h, show output
+	// of the test binary so that the help output is displayed
+	// even though the test will exit with success.
+	// This loop is imperfect: it will do the wrong thing for a case
+	// like -args -test.outputdir -help. Such cases are probably rare,
+	// and getting this wrong doesn't do too much harm.
+helpLoop:
+	for _, arg := range explicitArgs {
+		switch arg {
+		case "--":
+			break helpLoop
+		case "-h", "-help", "--help":
+			testHelp = true
+			break helpLoop
+		}
+	}
+
+	// Forward any unparsed arguments (following --args) to the test binary.
+	return packageNames, append(injectedFlags, explicitArgs...)
+}
+
+func exitWithUsage() {
+	fmt.Fprintf(os.Stderr, "usage: %s\n", CmdTest.UsageLine)
+	fmt.Fprintf(os.Stderr, "Run 'go help %s' and 'go help %s' for details.\n", CmdTest.LongName(), HelpTestflag.LongName())
+
+	base.SetExitStatus(2)
+	base.Exit()
+}