go: implement test command

Gotest tries to build things, for which it invokes make, and it was too hard to coordinate go invoking gotest invoking go to build the test binary, so put all the code here instead. Gotest will be deleted once we switch. The only code that really made sense to copy verbatim was the flag parsing. This remains a work in progress. There are still plenty of things to clean up and make better, but this is a good checkpoint. It can run all the tests in the tree (except runtime, which it can't build yet). $ go test all -short ok archive/tar ok archive/zip ok bufio ? builtin [no test files] ok bytes ok compress/bzip2 ok compress/flate ok compress/gzip ok compress/lzw ok compress/zlib ok container/heap ok container/list ok container/ring ? crypto [no test files] ok crypto/aes ok crypto/bcrypt ok crypto/blowfish ok crypto/cast5 ok crypto/cipher ok crypto/des ok crypto/dsa ok crypto/ecdsa ok crypto/elliptic ok crypto/hmac ok crypto/md4 ok crypto/md5 ok crypto/ocsp ok crypto/openpgp ok crypto/openpgp/armor ok crypto/openpgp/elgamal ? crypto/openpgp/error [no test files] ok crypto/openpgp/packet ok crypto/openpgp/s2k ok crypto/rand ok crypto/rc4 ok crypto/ripemd160 ok crypto/rsa ok crypto/sha1 ok crypto/sha256 ok crypto/sha512 ok crypto/subtle ok crypto/tls ok crypto/twofish ok crypto/x509 ? crypto/x509/pkix [no test files] ok crypto/xtea ok debug/dwarf ok debug/elf ok debug/gosym ok debug/macho ok debug/pe ok encoding/ascii85 ok encoding/asn1 ok encoding/base32 ok encoding/base64 ok encoding/binary ok encoding/csv ok encoding/git85 ok encoding/gob ok encoding/hex ok encoding/json ok encoding/pem ok encoding/xml ok errors ok exp/ebnf ? exp/ebnflint [no test files] ok exp/gotype ok exp/norm ok exp/spdy ok exp/sql ok exp/sql/driver ok exp/ssh ok exp/types ok expvar ok flag ok fmt ok go/ast ok go/build ok go/doc ok go/parser ok go/printer ok go/scanner ok go/token ? hash [no test files] ok hash/adler32 ok hash/crc32 ok hash/crc64 ok hash/fnv ok html ok html/template ok image ? image/bmp [no test files] ? image/color [no test files] ok image/draw ? image/gif [no test files] ok image/jpeg ok image/png ok image/tiff ok image/ycbcr ok index/suffixarray ok io ok io/ioutil ok log ok log/syslog ok math ok math/big ok math/cmplx ok math/rand ok mime ok mime/multipart ok net ? net/dict [no test files] ok net/http ok net/http/cgi ok net/http/fcgi ? net/http/httptest [no test files] ok net/http/httputil ? net/http/pprof [no test files] ok net/mail ok net/rpc ok net/rpc/jsonrpc ok net/smtp ok net/textproto ok net/url ok old/netchan ok old/regexp ok old/template ok os ok os/exec ok os/signal ok os/user ok patch ok path ok path/filepath ok reflect ok regexp ok regexp/syntax # cd /Users/rsc/g/go/src/pkg/runtime; 6g -o /var/folders/mw/qfnx8hhd1_s9mm9wtbng0hw80000gn/T/go-build874847916/runtime_test/_obj/_go_.6 -p runtime_test -I /var/folders/mw/qfnx8hhd1_s9mm9wtbng0hw80000gn/T/go-build874847916 append_test.go chan_test.go closure_test.go gc_test.go mfinal_test.go proc_test.go sema_test.go softfloat64_test.go symtab_test.go proc_test.go:87: undefined: runtime.Entersyscall proc_test.go:88: undefined: runtime.Exitsyscall proc_test.go:111: undefined: runtime.Entersyscall proc_test.go:116: undefined: runtime.Exitsyscall softfloat64_test.go:79: undefined: Fadd64 softfloat64_test.go:80: undefined: Fsub64 softfloat64_test.go:82: undefined: Fmul64 softfloat64_test.go:83: undefined: Fdiv64 softfloat64_test.go:94: undefined: F64to32 softfloat64_test.go:99: undefined: F32to64 softfloat64_test.go:99: too many errors exit status 1 FAIL runtime [build failed] ? runtime/cgo [no test files] ok runtime/debug ok runtime/pprof ok sort ok strconv ok strings ok sync ok sync/atomic ? syscall [no test files] ? testing [no test files] ? testing/iotest [no test files] ok testing/quick ok testing/script ok text/scanner ok text/tabwriter ok text/template ok text/template/parse ok time ok unicode ok unicode/utf16 ok unicode/utf8 ? unsafe [no test files] ok websocket $ R=golang-dev, r CC=golang-dev https://golang.org/cl/5495055
2024-11-20 05:14:41 -07:00 · 2011-12-15 23:51:04 -05:00 · 2011-12-15 23:51:04 -05:00 · 20090df70f
commit 20090df70f
parent 1338347b9c
6 changed files with 622 additions and 30 deletions
--- a/src/cmd/go/Makefile
+++ b/src/cmd/go/Makefile
@ -16,6 +16,7 @@ GOFILES=\
 	pkg.go\
 	run.go\
 	test.go\
+	testflag.go\
 	version.go\
 	vet.go\

--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@ -105,6 +105,7 @@ type builder struct {
 	nflag       bool                 // the -n flag
 	vflag       bool                 // the -v flag
 	arch        string               // e.g., "6"
+	goroot      string               // the $GOROOT
 	actionCache map[cacheKey]*action // a cache of already-constructed actions
 }

@ -116,6 +117,8 @@ type action struct {
 	deps       []*action // actions that must happen before this one
 	done       bool      // whether the action is done (might have failed)
 	failed     bool      // whether the action failed
+	pkgdir     string    // the -I or -L argument to use when importing this package
+	ignoreFail bool      // whether to run f even if dependencies fail

 	// Results left for communication with other code.
 	pkgobj string // the built .a file
@ -143,6 +146,7 @@ func (b *builder) init(aflag, nflag, vflag bool) {
 	b.nflag = nflag
 	b.vflag = vflag
 	b.actionCache = make(map[cacheKey]*action)
+	b.goroot = runtime.GOROOT()

 	b.arch, err = build.ArchChar(build.DefaultContext.GOARCH)
 	if err != nil {
@ -209,12 +213,24 @@ func (b *builder) action(mode buildMode, depMode buildMode, p *Package) *action
 		return a
 	}

-	a = &action{p: p}
+	a = &action{p: p, pkgdir: p.t.PkgDir()}
+	if p.pkgdir != "" { // overrides p.t
+		a.pkgdir = p.pkgdir
+	}
+
 	b.actionCache[key] = a

 	switch mode {
 	case modeBuild, modeInstall:
+		for _, p1 := range p.imports {
+			a.deps = append(a.deps, b.action(depMode, depMode, p1))
+		}
+
 		if !needInstall(p) && !b.aflag {
+			// TODO: This is not right if the deps above
+			// are not all no-ops too.  If fmt is up to date
+			// wrt its own source files,  but strconv has
+			// changed, then fmt is not up to date.
 			a.f = (*builder).nop
 			return a
 		}
@ -238,9 +254,6 @@ func (b *builder) action(mode buildMode, depMode buildMode, p *Package) *action
 		}

 		a.f = (*builder).build
-		for _, p1 := range p.imports {
-			a.deps = append(a.deps, b.action(depMode, depMode, p1))
-		}
 	}

 	return a
@ -288,10 +301,12 @@ func (b *builder) do(a *action) {
 		b.do(a1)
 		if a1.failed {
 			a.failed = true
+			if !a.ignoreFail {
 				a.done = true
 				return
 			}
 		}
+	}
 	if err := a.f(b, a); err != nil {
 		errorf("%s", err)
 		a.failed = true
@ -303,10 +318,12 @@ func (b *builder) nop(a *action) error {
 	return nil
 }

-// build is the action for building a single package.
+// build is the action for building a single package or command.
 func (b *builder) build(a *action) error {
 	obj := filepath.Join(b.work, filepath.FromSlash(a.p.ImportPath+"/_obj")) + string(filepath.Separator)
+	if a.pkgobj == "" {
 		a.pkgobj = filepath.Join(b.work, filepath.FromSlash(a.p.ImportPath+".a"))
+	}

 	// make build directory
 	if err := b.mkdir(obj); err != nil {
@ -332,11 +349,10 @@ func (b *builder) build(a *action) error {
 	inc = append(inc, "-I", b.work)
 	incMap := map[string]bool{}
 	for _, a1 := range a.deps {
-		p1 := a1.p
-		if p1.t.Goroot {
+		pkgdir := a1.pkgdir
+		if pkgdir == build.Path[0].PkgDir() || pkgdir == "" {
 			continue
 		}
-		pkgdir := p1.t.PkgDir()
 		if !incMap[pkgdir] {
 			incMap[pkgdir] = true
 			inc = append(inc, "-I", pkgdir)
@ -386,17 +402,14 @@ func (b *builder) build(a *action) error {

 // install is the action for installing a single package.
 func (b *builder) install(a *action) error {
-	if err := b.build(a); err != nil {
-		return err
-	}
-
+	a1 := a.deps[0]
 	var src string
 	var perm uint32
-	if a.pkgbin != "" {
-		src = a.pkgbin
+	if a1.pkgbin != "" {
+		src = a1.pkgbin
 		perm = 0777
 	} else {
-		src = a.pkgobj
+		src = a1.pkgobj
 		perm = 0666
 	}

--- a/src/cmd/go/main.go
+++ b/src/cmd/go/main.go
@ -36,6 +36,10 @@ type Command struct {

 	// Flag is a set of flags specific to this command.
 	Flag flag.FlagSet
+
+	// CustomFlags indicates that the command will do its own
+	// flag parsing.
+	CustomFlags bool
 }

 // Name returns the command's name: the first word in the usage line.
@ -96,8 +100,12 @@ func main() {
 	for _, cmd := range commands {
 		if cmd.Name() == args[0] && cmd.Run != nil {
 			cmd.Flag.Usage = func() { cmd.Usage() }
+			if cmd.CustomFlags {
+				args = args[1:]
+			} else {
 				cmd.Flag.Parse(args[1:])
 				args = cmd.Flag.Args()
+			}
 			cmd.Run(cmd, args)
 			exit()
 			return
@ -209,6 +217,8 @@ func errorf(format string, args ...interface{}) {
 	exitStatus = 1
 }

+var logf = log.Printf
+
 func exitIfErrors() {
 	if exitStatus != 0 {
 		exit()
--- a/src/cmd/go/pkg.go
+++ b/src/cmd/go/pkg.go
@ -38,6 +38,7 @@ type Package struct {

 	// Unexported fields are not part of the public API.
 	t       *build.Tree
+	pkgdir  string
 	info    *build.DirInfo
 	imports []*Package
 	gofiles []string // GoFiles+CgoFiles
--- a/src/cmd/go/test.go
+++ b/src/cmd/go/test.go
@ -4,8 +4,30 @@

 package main

+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/build"
+	"go/doc"
+	"go/parser"
+	"go/token"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"text/template"
+	"unicode"
+	"unicode/utf8"
+)
+
+// Break init loop.
+func init() {
+	cmdTest.Run = runTest
+}
+
 var cmdTest = &Command{
-	Run:       runTest,
+	CustomFlags: true,
 	UsageLine:   "test [importpath...] [-file a.go -file b.go ...] [-c] [-x] [flags for test binary]",
 	Short:       "test packages",
 	Long: `
@ -158,8 +180,385 @@ See the documentation of the testing package for more information.
 		`,
 }

+// TODO(rsc): Rethink the flag handling.
+// It might be better to do
+//	go test [go-test-flags] [importpaths] [flags for test binary]
+// If there are no import paths then the two flag sections
+// run together, but we can deal with that.  Right now, 
+//	go test -x  (ok)
+//	go test -x math (NOT OK)
+//	go test math -x (ok)
+// which is weird, because the -x really does apply to go test, not to math.
+// It is also possible that -file can go away.
+// For now just use the gotest code.
+
+var (
+	testC     bool     // -c flag
+	testX     bool     // -x flag
+	testFiles []string // -file flag(s)  TODO: not respected
+	testArgs  []string
+)
+
 func runTest(cmd *Command, args []string) {
-	args = importPaths(args)
-	_ = args
-	panic("test not implemented")
+	// Determine which are the import paths
+	// (leading arguments not starting with -).
+	i := 0
+	for i < len(args) && !strings.HasPrefix(args[i], "-") {
+		i++
+	}
+	pkgs := packages(args[:i])
+	if len(pkgs) == 0 {
+		fatalf("no packages to test")
+	}
+
+	testArgs = testFlags(args[i:])
+	if testC && len(pkgs) != 1 {
+		fatalf("cannot use -c flag with multiple packages")
+	}
+
+	var b builder
+	b.init(false, false, testX)
+
+	var builds, runs []*action
+
+	// Prepare build + run actions for all packages being tested.
+	for _, p := range pkgs {
+		buildTest, runTest, err := b.test(p)
+		if err != nil {
+			errorf("%s: %s", p, err)
+			continue
+		}
+		if buildTest == nil {
+			// no test at all
+			continue
+		}
+		builds = append(builds, buildTest)
+		runs = append(runs, runTest)
+	}
+
+	// Build+run the tests one at a time in the order
+	// specified on the command line.
+	// May want to revisit when we parallelize things,
+	// although probably not for benchmark runs.
+	for i, a := range builds {
+		if i > 0 {
+			// Make build of test i depend on
+			// completing the run of test i-1.
+			a.deps = append(a.deps, runs[i-1])
+		}
+	}
+
+	allRuns := &action{f: (*builder).nop, deps: runs}
+	b.do(allRuns)
 }
+
+func (b *builder) test(p *Package) (buildAction, runAction *action, err error) {
+	if len(p.info.TestGoFiles)+len(p.info.XTestGoFiles) == 0 {
+		return &action{f: (*builder).nop, p: p}, &action{f: (*builder).notest, p: p}, nil
+	}
+
+	// Build Package structs describing:
+	//	ptest - package + test files
+	//	pxtest - package of external test files
+	//	pmain - test.out binary
+	var ptest, pxtest, pmain *Package
+
+	// go/build does not distinguish the dependencies used
+	// by the TestGoFiles from the dependencies used by the
+	// XTestGoFiles, so we build one list and use it for both
+	// ptest and pxtest.  No harm done.
+	var imports []*Package
+	for _, path := range p.info.TestImports {
+		p1, err := loadPackage(path)
+		if err != nil {
+			return nil, nil, err
+		}
+		imports = append(imports, p1)
+	}
+
+	// The ptest package needs to be importable under the
+	// same import path that p has, but we cannot put it in
+	// the usual place in the temporary tree, because then
+	// other tests will see it as the real package.
+	// Instead we make a _test directory under the import path
+	// and then repeat the import path there.  We tell the
+	// compiler and linker to look in that _test directory first.
+	//
+	// That is, if the package under test is unicode/utf8,
+	// then the normal place to write the package archive is
+	// $WORK/unicode/utf8.a, but we write the test package archive to
+	// $WORK/unicode/utf8/_test/unicode/utf8.a.
+	// We write the external test package archive to
+	// $WORK/unicode/utf8/_test/unicode/utf8_test.a.
+	testDir := filepath.Join(b.work, filepath.FromSlash(p.ImportPath+"/_test"))
+	ptestObj := filepath.Join(testDir, filepath.FromSlash(p.ImportPath+".a"))
+
+	// Create the directory for the .a files.
+	ptestDir, _ := filepath.Split(ptestObj)
+	if err := b.mkdir(ptestDir); err != nil {
+		return nil, nil, err
+	}
+	if err := writeTestmain(filepath.Join(testDir, "_testmain.go"), p); err != nil {
+		return nil, nil, err
+	}
+
+	// Test package.
+	if len(p.info.TestGoFiles) > 0 {
+		ptest = new(Package)
+		*ptest = *p
+		ptest.GoFiles = nil
+		ptest.GoFiles = append(ptest.GoFiles, p.GoFiles...)
+		ptest.GoFiles = append(ptest.GoFiles, p.info.TestGoFiles...)
+		ptest.targ = "" // must rebuild
+		ptest.Imports = p.info.TestImports
+		ptest.imports = imports
+		ptest.pkgdir = testDir
+	} else {
+		ptest = p
+	}
+
+	// External test package.
+	if len(p.info.XTestGoFiles) > 0 {
+		pxtest = &Package{
+			Name:       p.Name + "_test",
+			ImportPath: p.ImportPath + "_test",
+			Dir:        p.Dir,
+			GoFiles:    p.info.XTestGoFiles,
+			Imports:    p.info.TestImports,
+			t:          p.t,
+			info:       &build.DirInfo{},
+			imports:    imports,
+			pkgdir:     testDir,
+		}
+	}
+
+	// Action for building test.out.
+	pmain = &Package{
+		Name:    "main",
+		Dir:     testDir,
+		GoFiles: []string{"_testmain.go"},
+		t:       p.t,
+		info:    &build.DirInfo{},
+		imports: []*Package{ptest},
+	}
+	if pxtest != nil {
+		pmain.imports = append(pmain.imports, pxtest)
+	}
+	pmainAction := b.action(modeBuild, modeBuild, pmain)
+	pmainAction.pkgbin = filepath.Join(testDir, "test.out")
+
+	if testC {
+		// -c flag: create action to copy binary to ./test.out.
+		pmain.targ = "test.out"
+		runAction = &action{
+			f:    (*builder).install,
+			deps: []*action{pmainAction},
+			p:    pmain,
+		}
+	} else {
+		// run test
+		runAction = &action{
+			f:          (*builder).runTest,
+			deps:       []*action{pmainAction},
+			p:          p,
+			ignoreFail: true,
+		}
+	}
+
+	return pmainAction, runAction, nil
+}
+
+var pass = []byte("\nPASS\n")
+
+// runTest is the action for running a test binary.
+func (b *builder) runTest(a *action) error {
+	if b.nflag || b.vflag {
+		b.showcmd("%s", strings.Join(append([]string{a.deps[0].pkgbin}, testArgs...), " "))
+		if b.nflag {
+			return nil
+		}
+	}
+
+	if a.failed {
+		// We were unable to build the binary.
+		a.failed = false
+		fmt.Printf("FAIL\t%s [build failed]\n", a.p.ImportPath)
+		exitStatus = 1
+		return nil
+	}
+
+	cmd := exec.Command(a.deps[0].pkgbin, testArgs...)
+	cmd.Dir = a.p.Dir
+	out, err := cmd.CombinedOutput()
+	if err == nil && (bytes.Equal(out, pass[1:]) || bytes.HasSuffix(out, pass)) {
+		fmt.Printf("ok  \t%s\n", a.p.ImportPath)
+		return nil
+	}
+
+	fmt.Printf("FAIL\t%s\n", a.p.ImportPath)
+	exitStatus = 1
+	if len(out) > 0 {
+		os.Stdout.Write(out)
+		// assume printing the test binary's exit status is superfluous
+	} else {
+		fmt.Printf("%s\n", err)
+	}
+	return nil
+}
+
+// notest is the action for testing a package with no test files.
+func (b *builder) notest(a *action) error {
+	fmt.Printf("?   \t%s [no test files]\n", a.p.ImportPath)
+	return nil
+}
+
+// isTest tells whether name looks like a test (or benchmark, according to prefix).
+// It is a Test (say) if there is a character after Test that is not a lower-case letter.
+// We don't want TesticularCancer.
+func isTest(name, prefix string) bool {
+	if !strings.HasPrefix(name, prefix) {
+		return false
+	}
+	if len(name) == len(prefix) { // "Test" is ok
+		return true
+	}
+	rune, _ := utf8.DecodeRuneInString(name[len(prefix):])
+	return !unicode.IsLower(rune)
+}
+
+// writeTestmain writes the _testmain.go file for package p to
+// the file named out.
+func writeTestmain(out string, p *Package) error {
+	t := &testFuncs{
+		Package: p,
+		Info:    p.info,
+	}
+	for _, file := range p.info.TestGoFiles {
+		if err := t.load(filepath.Join(p.Dir, file), "_test", &t.NeedTest); err != nil {
+			return err
+		}
+	}
+	for _, file := range p.info.XTestGoFiles {
+		if err := t.load(filepath.Join(p.Dir, file), "_xtest", &t.NeedXtest); err != nil {
+			return err
+		}
+	}
+
+	f, err := os.Create(out)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	if err := testmainTmpl.Execute(f, t); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+type testFuncs struct {
+	Tests      []testFunc
+	Benchmarks []testFunc
+	Examples   []testFunc
+	Package    *Package
+	Info       *build.DirInfo
+	NeedTest   bool
+	NeedXtest  bool
+}
+
+type testFunc struct {
+	Package string // imported package name (_test or _xtest)
+	Name    string // function name
+	Output  string // output, for examples
+}
+
+var testFileSet = token.NewFileSet()
+
+func (t *testFuncs) load(filename, pkg string, seen *bool) error {
+	f, err := parser.ParseFile(testFileSet, filename, nil, parser.ParseComments)
+	if err != nil {
+		return err
+	}
+	for _, d := range f.Decls {
+		n, ok := d.(*ast.FuncDecl)
+		if !ok {
+			continue
+		}
+		if n.Recv != nil {
+			continue
+		}
+		name := n.Name.String()
+		switch {
+		case isTest(name, "Test"):
+			t.Tests = append(t.Tests, testFunc{pkg, name, ""})
+			*seen = true
+		case isTest(name, "Benchmark"):
+			t.Benchmarks = append(t.Benchmarks, testFunc{pkg, name, ""})
+			*seen = true
+		case isTest(name, "Example"):
+			output := doc.CommentText(n.Doc)
+			if output == "" {
+				// Don't run examples with no output.
+				continue
+			}
+			t.Examples = append(t.Examples, testFunc{pkg, name, output})
+			*seen = true
+		}
+	}
+
+	return nil
+}
+
+var testmainTmpl = template.Must(template.New("main").Parse(`
+package main
+
+import (
+	"regexp"
+	"testing"
+
+{{if .NeedTest}}
+	_test {{.Package.ImportPath | printf "%q"}}
+{{end}}
+{{if .NeedXtest}}
+	_xtest {{.Package.ImportPath | printf "%s_test" | printf "%q"}}
+{{end}}
+)
+
+var tests = []testing.InternalTest{
+{{range .Tests}}
+	{"{{.Name}}", {{.Package}}.{{.Name}}},
+{{end}}
+}
+
+var benchmarks = []testing.InternalBenchmark{
+{{range .Benchmarks}}
+	{"{{.Name}}", {{.Package}}.{{.Name}}},
+{{end}}
+}
+
+var examples = []testing.InternalExample{
+{{range .Examples}}
+	{"{{.Name}}", {{.Package}}.{{.Name}}, {{.Output | printf "%q"}}},
+{{end}}
+}
+
+var matchPat string
+var matchRe *regexp.Regexp
+
+func matchString(pat, str string) (result bool, err error) {
+	if matchRe == nil || matchPat != pat {
+		matchPat = pat
+		matchRe, err = regexp.Compile(matchPat)
+		if err != nil {
+			return
+		}
+	}
+	return matchRe.MatchString(str), nil
+}
+
+func main() {
+	testing.Main(matchString, tests, benchmarks, examples)
+}
+
+`))
--- a/src/cmd/go/testflag.go
+++ b/src/cmd/go/testflag.go
@ -0,0 +1,168 @@
+// 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 main
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// The flag handling part of go test is large and distracting.
+// We can't use the flag package because some of the flags from
+// our command line are for us, and some are for 6.out, and
+// some are for both.
+
+var usageMessage = `Usage of go test:
+  -c=false: compile but do not run the test binary
+  -file=file_test.go: specify file to use for tests;
+      use multiple times for multiple files
+  -x=false: print command lines as they are executed
+
+  // These flags can be passed with or without a "test." prefix: -v or -test.v.
+  -bench="": passes -test.bench to test
+  -benchtime=1: passes -test.benchtime to test
+  -cpu="": passes -test.cpu to test
+  -cpuprofile="": passes -test.cpuprofile to test
+  -memprofile="": passes -test.memprofile to test
+  -memprofilerate=0: passes -test.memprofilerate to test
+  -parallel=0: passes -test.parallel to test
+  -run="": passes -test.run to test
+  -short=false: passes -test.short to test
+  -timeout=0: passes -test.timeout to test
+  -v=false: passes -test.v to test
+`
+
+// usage prints a usage message and exits.
+func testUsage() {
+	fmt.Fprint(os.Stderr, usageMessage)
+	exitStatus = 2
+	exit()
+}
+
+// testFlagSpec defines a flag we know about.
+type testFlagSpec struct {
+	name       string
+	isBool     bool
+	passToTest bool // pass to Test
+	multiOK    bool // OK to have multiple instances
+	present    bool // flag has been seen
+}
+
+// testFlagDefn is the set of flags we process.
+var testFlagDefn = []*testFlagSpec{
+	// local.
+	{name: "c", isBool: true},
+	{name: "file", multiOK: true},
+	{name: "x", isBool: true},
+
+	// passed to 6.out, adding a "test." prefix to the name if necessary: -v becomes -test.v.
+	{name: "bench", passToTest: true},
+	{name: "benchtime", passToTest: true},
+	{name: "cpu", passToTest: true},
+	{name: "cpuprofile", passToTest: true},
+	{name: "memprofile", passToTest: true},
+	{name: "memprofilerate", passToTest: true},
+	{name: "parallel", passToTest: true},
+	{name: "run", passToTest: true},
+	{name: "short", isBool: true, passToTest: true},
+	{name: "timeout", passToTest: true},
+	{name: "v", isBool: true, passToTest: true},
+}
+
+// testFlags processes the command line, grabbing -x and -c, rewriting known flags
+// to have "test" before them, and reading the command line for the 6.out.
+// 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
+// test.out's arguments.
+func testFlags(args []string) (passToTest []string) {
+	for i := 0; i < len(args); i++ {
+		arg := args[i]
+		f, value, extraWord := testFlag(args, i)
+		if f == nil {
+			args = append(args, arg)
+			continue
+		}
+		switch f.name {
+		case "c":
+			setBoolFlag(&testC, value)
+		case "x":
+			setBoolFlag(&testX, value)
+		case "file":
+			testFiles = append(testFiles, value)
+		}
+		if extraWord {
+			i++
+		}
+		if f.passToTest {
+			passToTest = append(passToTest, "-test."+f.name+"="+value)
+		}
+	}
+	return
+}
+
+// testFlag sees if argument i is a known flag and returns its definition, value, and whether it consumed an extra word.
+func testFlag(args []string, i int) (f *testFlagSpec, value string, extra bool) {
+	arg := args[i]
+	if strings.HasPrefix(arg, "--") { // reduce two minuses to one
+		arg = arg[1:]
+	}
+	switch arg {
+	case "-?", "-h", "-help":
+		usage()
+	}
+	if arg == "" || arg[0] != '-' {
+		return
+	}
+	name := arg[1:]
+	// If there's already "test.", drop it for now.
+	if strings.HasPrefix(name, "test.") {
+		name = name[5:]
+	}
+	equals := strings.Index(name, "=")
+	if equals >= 0 {
+		value = name[equals+1:]
+		name = name[:equals]
+	}
+	for _, f = range testFlagDefn {
+		if name == f.name {
+			// Booleans are special because they have modes -x, -x=true, -x=false.
+			if f.isBool {
+				if equals < 0 { // otherwise, it's been set and will be verified in setBoolFlag
+					value = "true"
+				} else {
+					// verify it parses
+					setBoolFlag(new(bool), value)
+				}
+			} else { // Non-booleans must have a value.
+				extra = equals < 0
+				if extra {
+					if i+1 >= len(args) {
+						usage()
+					}
+					value = args[i+1]
+				}
+			}
+			if f.present && !f.multiOK {
+				usage()
+			}
+			f.present = true
+			return
+		}
+	}
+	f = nil
+	return
+}
+
+// setBoolFlag sets the addressed boolean to the value.
+func setBoolFlag(flag *bool, value string) {
+	x, err := strconv.ParseBool(value)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "go test: illegal bool flag value %s\n", value)
+		usage()
+	}
+	*flag = x
+}