go/internal/gcimporter/gcimporter_test.go - tools - Git at Google

 // 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.

 // This file is a copy of $GOROOT/src/go/internal/gcimporter/gcimporter_test.go,
 // adjusted to make it build with code from (std lib) internal/testenv copied.

 package gcimporter

 import (
 	"bytes"
 	"fmt"
 	"go/types"
 	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strings"
 	"testing"
 	"time"

 	"golang.org/x/tools/internal/testenv"
 )

 func TestMain(m *testing.M) {
 	testenv.ExitIfSmallMachine()
 	os.Exit(m.Run())
 }

 // ----------------------------------------------------------------------------
 // The following three functions (Builder, HasGoBuild, MustHaveGoBuild) were
 // copied from $GOROOT/src/internal/testenv since that package is not available
 // in x/tools.

 // Builder reports the name of the builder running this test
 // (for example, "linux-amd64" or "windows-386-gce").
 // If the test is not running on the build infrastructure,
 // Builder returns the empty string.
 func Builder() string {
 	return os.Getenv("GO_BUILDER_NAME")
 }

 // HasGoBuild reports whether the current system can build programs with ``go build''
 // and then run them with os.StartProcess or exec.Command.
 func HasGoBuild() bool {
 	switch runtime.GOOS {
 	case "android", "nacl":
 		return false
 	case "darwin":
 		if strings.HasPrefix(runtime.GOARCH, "arm") {
 			return false
 		}
 	}
 	return true
 }

 // MustHaveGoBuild checks that the current system can build programs with ``go build''
 // and then run them with os.StartProcess or exec.Command.
 // If not, MustHaveGoBuild calls t.Skip with an explanation.
 func MustHaveGoBuild(t *testing.T) {
 	testenv.NeedsTool(t, "go")
 	if !HasGoBuild() {
 		t.Skipf("skipping test: 'go build' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
 	}
 }

 // ----------------------------------------------------------------------------

 // skipSpecialPlatforms causes the test to be skipped for platforms where
 // builders (build.golang.org) don't have access to compiled packages for
 // import.
 func skipSpecialPlatforms(t *testing.T) {
 	switch platform := runtime.GOOS + "-" + runtime.GOARCH; platform {
 	case "nacl-amd64p32",
 		"nacl-386",
 		"nacl-arm",
 		"darwin-arm",
 		"darwin-arm64":
 		t.Skipf("no compiled packages available for import on %s", platform)
 	}
 }

 // compile runs the compiler on filename, with dirname as the working directory,
 // and writes the output file to outdirname.
 func compile(t *testing.T, dirname, filename, outdirname string) string {
 	/* testenv. */ MustHaveGoBuild(t)
 	// filename must end with ".go"
 	if !strings.HasSuffix(filename, ".go") {
 		t.Fatalf("filename doesn't end in .go: %s", filename)
 	}
 	basename := filepath.Base(filename)
 	outname := filepath.Join(outdirname, basename[:len(basename)-2]+"o")
 	cmd := exec.Command("go", "tool", "compile", "-o", outname, filename)
 	cmd.Dir = dirname
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		t.Logf("%s", out)
 		t.Fatalf("go tool compile %s failed: %s", filename, err)
 	}
 	return outname
 }

 func testPath(t *testing.T, path, srcDir string) *types.Package {
 	t0 := time.Now()
 	pkg, err := Import(make(map[string]*types.Package), path, srcDir, nil)
 	if err != nil {
 		t.Errorf("testPath(%s): %s", path, err)
 		return nil
 	}
 	t.Logf("testPath(%s): %v", path, time.Since(t0))
 	return pkg
 }

 const maxTime = 30 * time.Second

 func testDir(t *testing.T, dir string, endTime time.Time) (nimports int) {
 	dirname := filepath.Join(runtime.GOROOT(), "pkg", runtime.GOOS+"_"+runtime.GOARCH, dir)
 	list, err := ioutil.ReadDir(dirname)
 	if err != nil {
 		t.Fatalf("testDir(%s): %s", dirname, err)
 	}
 	for _, f := range list {
 		if time.Now().After(endTime) {
 			t.Log("testing time used up")
 			return
 		}
 		switch {
 		case !f.IsDir():
 			// try extensions
 			for _, ext := range pkgExts {
 				if strings.HasSuffix(f.Name(), ext) {
 					name := f.Name()[0 : len(f.Name())-len(ext)] // remove extension
 					if testPath(t, filepath.Join(dir, name), dir) != nil {
 						nimports++
 					}
 				}
 			}
 		case f.IsDir():
 			nimports += testDir(t, filepath.Join(dir, f.Name()), endTime)
 		}
 	}
 	return
 }

 func mktmpdir(t *testing.T) string {
 	tmpdir, err := ioutil.TempDir("", "gcimporter_test")
 	if err != nil {
 		t.Fatal("mktmpdir:", err)
 	}
 	if err := os.Mkdir(filepath.Join(tmpdir, "testdata"), 0700); err != nil {
 		os.RemoveAll(tmpdir)
 		t.Fatal("mktmpdir:", err)
 	}
 	return tmpdir
 }

 const testfile = "exports.go"

 func TestImportTestdata(t *testing.T) {
 	// This package only handles gc export data.
 	if runtime.Compiler != "gc" {
 		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
 	}

 	tmpdir := mktmpdir(t)
 	defer os.RemoveAll(tmpdir)

 	compile(t, "testdata", testfile, filepath.Join(tmpdir, "testdata"))

 	// filename should end with ".go"
 	filename := testfile[:len(testfile)-3]
 	if pkg := testPath(t, "./testdata/"+filename, tmpdir); pkg != nil {
 		// The package's Imports list must include all packages
 		// explicitly imported by testfile, plus all packages
 		// referenced indirectly via exported objects in testfile.
 		// With the textual export format (when run against Go1.6),
 		// the list may also include additional packages that are
 		// not strictly required for import processing alone (they
 		// are exported to err "on the safe side").
 		// For now, we just test the presence of a few packages
 		// that we know are there for sure.
 		got := fmt.Sprint(pkg.Imports())
 		for _, want := range []string{"go/ast", "go/token"} {
 			if !strings.Contains(got, want) {
 				t.Errorf(`Package("exports").Imports() = %s, does not contain %s`, got, want)
 			}
 		}
 	}
 }

 func TestVersionHandling(t *testing.T) {
 	skipSpecialPlatforms(t) // we really only need to exclude nacl platforms, but this is fine

 	// This package only handles gc export data.
 	if runtime.Compiler != "gc" {
 		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
 	}

 	const dir = "./testdata/versions"
 	list, err := ioutil.ReadDir(dir)
 	if err != nil {
 		t.Fatal(err)
 	}

 	tmpdir := mktmpdir(t)
 	defer os.RemoveAll(tmpdir)
 	corruptdir := filepath.Join(tmpdir, "testdata", "versions")
 	if err := os.Mkdir(corruptdir, 0700); err != nil {
 		t.Fatal(err)
 	}

 	for _, f := range list {
 		name := f.Name()
 		if !strings.HasSuffix(name, ".a") {
 			continue // not a package file
 		}
 		if strings.Contains(name, "corrupted") {
 			continue // don't process a leftover corrupted file
 		}
 		pkgpath := "./" + name[:len(name)-2]

 		if testing.Verbose() {
 			t.Logf("importing %s", name)
 		}

 		// test that export data can be imported
 		_, err := Import(make(map[string]*types.Package), pkgpath, dir, nil)
 		if err != nil {
 			// ok to fail if it fails with a newer version error for select files
 			if strings.Contains(err.Error(), "newer version") {
 				switch name {
 				case "test_go1.11_999b.a", "test_go1.11_999i.a":
 					continue
 				}
 				// fall through
 			}
 			t.Errorf("import %q failed: %v", pkgpath, err)
 			continue
 		}

 		// create file with corrupted export data
 		// 1) read file
 		data, err := ioutil.ReadFile(filepath.Join(dir, name))
 		if err != nil {
 			t.Fatal(err)
 		}
 		// 2) find export data
 		i := bytes.Index(data, []byte("\n$$B\n")) + 5
 		j := bytes.Index(data[i:], []byte("\n$$\n")) + i
 		if i < 0 || j < 0 || i > j {
 			t.Fatalf("export data section not found (i = %d, j = %d)", i, j)
 		}
 		// 3) corrupt the data (increment every 7th byte)
 		for k := j - 13; k >= i; k -= 7 {
 			data[k]++
 		}
 		// 4) write the file
 		pkgpath += "_corrupted"
 		filename := filepath.Join(corruptdir, pkgpath) + ".a"
 		ioutil.WriteFile(filename, data, 0666)

 		// test that importing the corrupted file results in an error
 		_, err = Import(make(map[string]*types.Package), pkgpath, corruptdir, nil)
 		if err == nil {
 			t.Errorf("import corrupted %q succeeded", pkgpath)
 		} else if msg := err.Error(); !strings.Contains(msg, "version skew") {
 			t.Errorf("import %q error incorrect (%s)", pkgpath, msg)
 		}
 	}
 }

 func TestImportStdLib(t *testing.T) {
 	skipSpecialPlatforms(t)

 	// This package only handles gc export data.
 	if runtime.Compiler != "gc" {
 		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
 	}

 	dt := maxTime
 	if testing.Short() && /* testenv. */ Builder() == "" {
 		dt = 10 * time.Millisecond
 	}
 	nimports := testDir(t, "", time.Now().Add(dt)) // installed packages
 	t.Logf("tested %d imports", nimports)
 }

 func TestIssue5815(t *testing.T) {
 	skipSpecialPlatforms(t)

 	// This package only handles gc export data.
 	if runtime.Compiler != "gc" {
 		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
 	}

 	pkg := importPkg(t, "strings", ".")

 	scope := pkg.Scope()
 	for _, name := range scope.Names() {
 		obj := scope.Lookup(name)
 		if obj.Pkg() == nil {
 			t.Errorf("no pkg for %s", obj)
 		}
 		if tname, _ := obj.(*types.TypeName); tname != nil {
 			named := tname.Type().(*types.Named)
 			for i := 0; i < named.NumMethods(); i++ {
 				m := named.Method(i)
 				if m.Pkg() == nil {
 					t.Errorf("no pkg for %s", m)
 				}
 			}
 		}
 	}
 }

 // Smoke test to ensure that imported methods get the correct package.
 func TestCorrectMethodPackage(t *testing.T) {
 	skipSpecialPlatforms(t)

 	// This package only handles gc export data.
 	if runtime.Compiler != "gc" {
 		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
 	}

 	imports := make(map[string]*types.Package)
 	_, err := Import(imports, "net/http", ".", nil)
 	if err != nil {
 		t.Fatal(err)
 	}

 	mutex := imports["sync"].Scope().Lookup("Mutex").(*types.TypeName).Type()
 	mset := types.NewMethodSet(types.NewPointer(mutex)) // methods of *sync.Mutex
 	sel := mset.Lookup(nil, "Lock")
 	lock := sel.Obj().(*types.Func)
 	if got, want := lock.Pkg().Path(), "sync"; got != want {
 		t.Errorf("got package path %q; want %q", got, want)
 	}
 }

 func TestIssue13566(t *testing.T) {
 	skipSpecialPlatforms(t)

 	// This package only handles gc export data.
 	if runtime.Compiler != "gc" {
 		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
 	}

 	// On windows, we have to set the -D option for the compiler to avoid having a drive
 	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
 	if runtime.GOOS == "windows" {
 		t.Skip("avoid dealing with relative paths/drive letters on windows")
 	}

 	tmpdir := mktmpdir(t)
 	defer os.RemoveAll(tmpdir)
 	testoutdir := filepath.Join(tmpdir, "testdata")

 	// b.go needs to be compiled from the output directory so that the compiler can
 	// find the compiled package a. We pass the full path to compile() so that we
 	// don't have to copy the file to that directory.
 	bpath, err := filepath.Abs(filepath.Join("testdata", "b.go"))
 	if err != nil {
 		t.Fatal(err)
 	}
 	compile(t, "testdata", "a.go", testoutdir)
 	compile(t, testoutdir, bpath, testoutdir)

 	// import must succeed (test for issue at hand)
 	pkg := importPkg(t, "./testdata/b", tmpdir)

 	// make sure all indirectly imported packages have names
 	for _, imp := range pkg.Imports() {
 		if imp.Name() == "" {
 			t.Errorf("no name for %s package", imp.Path())
 		}
 	}
 }

 func TestIssue13898(t *testing.T) {
 	skipSpecialPlatforms(t)

 	// This package only handles gc export data.
 	if runtime.Compiler != "gc" {
 		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
 	}

 	// import go/internal/gcimporter which imports go/types partially
 	imports := make(map[string]*types.Package)
 	_, err := Import(imports, "go/internal/gcimporter", ".", nil)
 	if err != nil {
 		t.Fatal(err)
 	}

 	// look for go/types package
 	var goTypesPkg *types.Package
 	for path, pkg := range imports {
 		if path == "go/types" {
 			goTypesPkg = pkg
 			break
 		}
 	}
 	if goTypesPkg == nil {
 		t.Fatal("go/types not found")
 	}

 	// look for go/types.Object type
 	obj := lookupObj(t, goTypesPkg.Scope(), "Object")
 	typ, ok := obj.Type().(*types.Named)
 	if !ok {
 		t.Fatalf("go/types.Object type is %v; wanted named type", typ)
 	}

 	// lookup go/types.Object.Pkg method
 	m, index, indirect := types.LookupFieldOrMethod(typ, false, nil, "Pkg")
 	if m == nil {
 		t.Fatalf("go/types.Object.Pkg not found (index = %v, indirect = %v)", index, indirect)
 	}

 	// the method must belong to go/types
 	if m.Pkg().Path() != "go/types" {
 		t.Fatalf("found %v; want go/types", m.Pkg())
 	}
 }

 func TestIssue15517(t *testing.T) {
 	skipSpecialPlatforms(t)

 	// This package only handles gc export data.
 	if runtime.Compiler != "gc" {
 		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
 	}

 	// On windows, we have to set the -D option for the compiler to avoid having a drive
 	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
 	if runtime.GOOS == "windows" {
 		t.Skip("avoid dealing with relative paths/drive letters on windows")
 	}

 	tmpdir := mktmpdir(t)
 	defer os.RemoveAll(tmpdir)

 	compile(t, "testdata", "p.go", filepath.Join(tmpdir, "testdata"))

 	// Multiple imports of p must succeed without redeclaration errors.
 	// We use an import path that's not cleaned up so that the eventual
 	// file path for the package is different from the package path; this
 	// will expose the error if it is present.
 	//
 	// (Issue: Both the textual and the binary importer used the file path
 	// of the package to be imported as key into the shared packages map.
 	// However, the binary importer then used the package path to identify
 	// the imported package to mark it as complete; effectively marking the
 	// wrong package as complete. By using an "unclean" package path, the
 	// file and package path are different, exposing the problem if present.
 	// The same issue occurs with vendoring.)
 	imports := make(map[string]*types.Package)
 	for i := 0; i < 3; i++ {
 		if _, err := Import(imports, "./././testdata/p", tmpdir, nil); err != nil {
 			t.Fatal(err)
 		}
 	}
 }

 func TestIssue15920(t *testing.T) {
 	skipSpecialPlatforms(t)

 	// This package only handles gc export data.
 	if runtime.Compiler != "gc" {
 		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
 	}

 	// On windows, we have to set the -D option for the compiler to avoid having a drive
 	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
 	if runtime.GOOS == "windows" {
 		t.Skip("avoid dealing with relative paths/drive letters on windows")
 	}

 	compileAndImportPkg(t, "issue15920")
 }

 func TestIssue20046(t *testing.T) {
 	skipSpecialPlatforms(t)

 	// This package only handles gc export data.
 	if runtime.Compiler != "gc" {
 		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
 	}

 	// On windows, we have to set the -D option for the compiler to avoid having a drive
 	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
 	if runtime.GOOS == "windows" {
 		t.Skip("avoid dealing with relative paths/drive letters on windows")
 	}

 	// "./issue20046".V.M must exist
 	pkg := compileAndImportPkg(t, "issue20046")
 	obj := lookupObj(t, pkg.Scope(), "V")
 	if m, index, indirect := types.LookupFieldOrMethod(obj.Type(), false, nil, "M"); m == nil {
 		t.Fatalf("V.M not found (index = %v, indirect = %v)", index, indirect)
 	}
 }

 func importPkg(t *testing.T, path, srcDir string) *types.Package {
 	pkg, err := Import(make(map[string]*types.Package), path, srcDir, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
 	return pkg
 }

 func compileAndImportPkg(t *testing.T, name string) *types.Package {
 	tmpdir := mktmpdir(t)
 	defer os.RemoveAll(tmpdir)
 	compile(t, "testdata", name+".go", filepath.Join(tmpdir, "testdata"))
 	return importPkg(t, "./testdata/"+name, tmpdir)
 }

 func lookupObj(t *testing.T, scope *types.Scope, name string) types.Object {
 	if obj := scope.Lookup(name); obj != nil {
 		return obj
 	}
 	t.Fatalf("%s not found", name)
 	return nil
 }
	// 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.

	// This file is a copy of $GOROOT/src/go/internal/gcimporter/gcimporter_test.go,
	// adjusted to make it build with code from (std lib) internal/testenv copied.

	package gcimporter

	import (
	"bytes"
	"fmt"
	"go/types"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"testing"
	"time"

	"golang.org/x/tools/internal/testenv"
	)

	func TestMain(m *testing.M) {
	testenv.ExitIfSmallMachine()
	os.Exit(m.Run())
	}

	// ----------------------------------------------------------------------------
	// The following three functions (Builder, HasGoBuild, MustHaveGoBuild) were
	// copied from $GOROOT/src/internal/testenv since that package is not available
	// in x/tools.

	// Builder reports the name of the builder running this test
	// (for example, "linux-amd64" or "windows-386-gce").
	// If the test is not running on the build infrastructure,
	// Builder returns the empty string.
	func Builder() string {
	return os.Getenv("GO_BUILDER_NAME")
	}

	// HasGoBuild reports whether the current system can build programs with ``go build''
	// and then run them with os.StartProcess or exec.Command.
	func HasGoBuild() bool {
	switch runtime.GOOS {
	case "android", "nacl":
	return false
	case "darwin":
	if strings.HasPrefix(runtime.GOARCH, "arm") {
	return false
	}
	}
	return true
	}

	// MustHaveGoBuild checks that the current system can build programs with ``go build''
	// and then run them with os.StartProcess or exec.Command.
	// If not, MustHaveGoBuild calls t.Skip with an explanation.
	func MustHaveGoBuild(t *testing.T) {
	testenv.NeedsTool(t, "go")
	if !HasGoBuild() {
	t.Skipf("skipping test: 'go build' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
	}
	}

	// ----------------------------------------------------------------------------

	// skipSpecialPlatforms causes the test to be skipped for platforms where
	// builders (build.golang.org) don't have access to compiled packages for
	// import.
	func skipSpecialPlatforms(t *testing.T) {
	switch platform := runtime.GOOS + "-" + runtime.GOARCH; platform {
	case "nacl-amd64p32",
	"nacl-386",
	"nacl-arm",
	"darwin-arm",
	"darwin-arm64":
	t.Skipf("no compiled packages available for import on %s", platform)
	}
	}

	// compile runs the compiler on filename, with dirname as the working directory,
	// and writes the output file to outdirname.
	func compile(t *testing.T, dirname, filename, outdirname string) string {
	/* testenv. */ MustHaveGoBuild(t)
	// filename must end with ".go"
	if !strings.HasSuffix(filename, ".go") {
	t.Fatalf("filename doesn't end in .go: %s", filename)
	}
	basename := filepath.Base(filename)
	outname := filepath.Join(outdirname, basename[:len(basename)-2]+"o")
	cmd := exec.Command("go", "tool", "compile", "-o", outname, filename)
	cmd.Dir = dirname
	out, err := cmd.CombinedOutput()
	if err != nil {
	t.Logf("%s", out)
	t.Fatalf("go tool compile %s failed: %s", filename, err)
	}
	return outname
	}

	func testPath(t testing.T, path, srcDir string) types.Package {
	t0 := time.Now()
	pkg, err := Import(make(map[string]*types.Package), path, srcDir, nil)
	if err != nil {
	t.Errorf("testPath(%s): %s", path, err)
	return nil
	}
	t.Logf("testPath(%s): %v", path, time.Since(t0))
	return pkg
	}

	const maxTime = 30 * time.Second

	func testDir(t *testing.T, dir string, endTime time.Time) (nimports int) {
	dirname := filepath.Join(runtime.GOROOT(), "pkg", runtime.GOOS+"_"+runtime.GOARCH, dir)
	list, err := ioutil.ReadDir(dirname)
	if err != nil {
	t.Fatalf("testDir(%s): %s", dirname, err)
	}
	for _, f := range list {
	if time.Now().After(endTime) {
	t.Log("testing time used up")
	return
	}
	switch {
	case !f.IsDir():
	// try extensions
	for _, ext := range pkgExts {
	if strings.HasSuffix(f.Name(), ext) {
	name := f.Name()[0 : len(f.Name())-len(ext)] // remove extension
	if testPath(t, filepath.Join(dir, name), dir) != nil {
	nimports++
	}
	}
	}
	case f.IsDir():
	nimports += testDir(t, filepath.Join(dir, f.Name()), endTime)
	}
	}
	return
	}

	func mktmpdir(t *testing.T) string {
	tmpdir, err := ioutil.TempDir("", "gcimporter_test")
	if err != nil {
	t.Fatal("mktmpdir:", err)
	}
	if err := os.Mkdir(filepath.Join(tmpdir, "testdata"), 0700); err != nil {
	os.RemoveAll(tmpdir)
	t.Fatal("mktmpdir:", err)
	}
	return tmpdir
	}

	const testfile = "exports.go"

	func TestImportTestdata(t *testing.T) {
	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
	t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
	}

	tmpdir := mktmpdir(t)
	defer os.RemoveAll(tmpdir)

	compile(t, "testdata", testfile, filepath.Join(tmpdir, "testdata"))

	// filename should end with ".go"
	filename := testfile[:len(testfile)-3]
	if pkg := testPath(t, "./testdata/"+filename, tmpdir); pkg != nil {
	// The package's Imports list must include all packages
	// explicitly imported by testfile, plus all packages
	// referenced indirectly via exported objects in testfile.
	// With the textual export format (when run against Go1.6),
	// the list may also include additional packages that are
	// not strictly required for import processing alone (they
	// are exported to err "on the safe side").
	// For now, we just test the presence of a few packages
	// that we know are there for sure.
	got := fmt.Sprint(pkg.Imports())
	for _, want := range []string{"go/ast", "go/token"} {
	if !strings.Contains(got, want) {
	t.Errorf(`Package("exports").Imports() = %s, does not contain %s`, got, want)
	}
	}
	}
	}

	func TestVersionHandling(t *testing.T) {
	skipSpecialPlatforms(t) // we really only need to exclude nacl platforms, but this is fine

	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
	t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
	}

	const dir = "./testdata/versions"
	list, err := ioutil.ReadDir(dir)
	if err != nil {
	t.Fatal(err)
	}

	tmpdir := mktmpdir(t)
	defer os.RemoveAll(tmpdir)
	corruptdir := filepath.Join(tmpdir, "testdata", "versions")
	if err := os.Mkdir(corruptdir, 0700); err != nil {
	t.Fatal(err)
	}

	for _, f := range list {
	name := f.Name()
	if !strings.HasSuffix(name, ".a") {
	continue // not a package file
	}
	if strings.Contains(name, "corrupted") {
	continue // don't process a leftover corrupted file
	}
	pkgpath := "./" + name[:len(name)-2]

	if testing.Verbose() {
	t.Logf("importing %s", name)
	}

	// test that export data can be imported
	_, err := Import(make(map[string]*types.Package), pkgpath, dir, nil)
	if err != nil {
	// ok to fail if it fails with a newer version error for select files
	if strings.Contains(err.Error(), "newer version") {
	switch name {
	case "test_go1.11_999b.a", "test_go1.11_999i.a":
	continue
	}
	// fall through
	}
	t.Errorf("import %q failed: %v", pkgpath, err)
	continue
	}

	// create file with corrupted export data
	// 1) read file
	data, err := ioutil.ReadFile(filepath.Join(dir, name))
	if err != nil {
	t.Fatal(err)
	}
	// 2) find export data
	i := bytes.Index(data, []byte("\n$$B\n")) + 5
	j := bytes.Index(data[i:], []byte("\n$$\n")) + i
	if i < 0 \|\| j < 0 \|\| i > j {
	t.Fatalf("export data section not found (i = %d, j = %d)", i, j)
	}
	// 3) corrupt the data (increment every 7th byte)
	for k := j - 13; k >= i; k -= 7 {
	data[k]++
	}
	// 4) write the file
	pkgpath += "_corrupted"
	filename := filepath.Join(corruptdir, pkgpath) + ".a"
	ioutil.WriteFile(filename, data, 0666)

	// test that importing the corrupted file results in an error
	_, err = Import(make(map[string]*types.Package), pkgpath, corruptdir, nil)
	if err == nil {
	t.Errorf("import corrupted %q succeeded", pkgpath)
	} else if msg := err.Error(); !strings.Contains(msg, "version skew") {
	t.Errorf("import %q error incorrect (%s)", pkgpath, msg)
	}
	}
	}

	func TestImportStdLib(t *testing.T) {
	skipSpecialPlatforms(t)

	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
	t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
	}

	dt := maxTime
	if testing.Short() && /* testenv. */ Builder() == "" {
	dt = 10 * time.Millisecond
	}
	nimports := testDir(t, "", time.Now().Add(dt)) // installed packages
	t.Logf("tested %d imports", nimports)
	}

	func TestIssue5815(t *testing.T) {
	skipSpecialPlatforms(t)

	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
	t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
	}

	pkg := importPkg(t, "strings", ".")

	scope := pkg.Scope()
	for _, name := range scope.Names() {
	obj := scope.Lookup(name)
	if obj.Pkg() == nil {
	t.Errorf("no pkg for %s", obj)
	}
	if tname, _ := obj.(*types.TypeName); tname != nil {
	named := tname.Type().(*types.Named)
	for i := 0; i < named.NumMethods(); i++ {
	m := named.Method(i)
	if m.Pkg() == nil {
	t.Errorf("no pkg for %s", m)
	}
	}
	}
	}
	}

	// Smoke test to ensure that imported methods get the correct package.
	func TestCorrectMethodPackage(t *testing.T) {
	skipSpecialPlatforms(t)

	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
	t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
	}

	imports := make(map[string]*types.Package)
	_, err := Import(imports, "net/http", ".", nil)
	if err != nil {
	t.Fatal(err)
	}

	mutex := imports["sync"].Scope().Lookup("Mutex").(*types.TypeName).Type()
	mset := types.NewMethodSet(types.NewPointer(mutex)) // methods of *sync.Mutex
	sel := mset.Lookup(nil, "Lock")
	lock := sel.Obj().(*types.Func)
	if got, want := lock.Pkg().Path(), "sync"; got != want {
	t.Errorf("got package path %q; want %q", got, want)
	}
	}

	func TestIssue13566(t *testing.T) {
	skipSpecialPlatforms(t)

	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
	t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
	}

	// On windows, we have to set the -D option for the compiler to avoid having a drive
	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
	if runtime.GOOS == "windows" {
	t.Skip("avoid dealing with relative paths/drive letters on windows")
	}

	tmpdir := mktmpdir(t)
	defer os.RemoveAll(tmpdir)
	testoutdir := filepath.Join(tmpdir, "testdata")

	// b.go needs to be compiled from the output directory so that the compiler can
	// find the compiled package a. We pass the full path to compile() so that we
	// don't have to copy the file to that directory.
	bpath, err := filepath.Abs(filepath.Join("testdata", "b.go"))
	if err != nil {
	t.Fatal(err)
	}
	compile(t, "testdata", "a.go", testoutdir)
	compile(t, testoutdir, bpath, testoutdir)

	// import must succeed (test for issue at hand)
	pkg := importPkg(t, "./testdata/b", tmpdir)

	// make sure all indirectly imported packages have names
	for _, imp := range pkg.Imports() {
	if imp.Name() == "" {
	t.Errorf("no name for %s package", imp.Path())
	}
	}
	}

	func TestIssue13898(t *testing.T) {
	skipSpecialPlatforms(t)

	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
	t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
	}

	// import go/internal/gcimporter which imports go/types partially
	imports := make(map[string]*types.Package)
	_, err := Import(imports, "go/internal/gcimporter", ".", nil)
	if err != nil {
	t.Fatal(err)
	}

	// look for go/types package
	var goTypesPkg *types.Package
	for path, pkg := range imports {
	if path == "go/types" {
	goTypesPkg = pkg
	break
	}
	}
	if goTypesPkg == nil {
	t.Fatal("go/types not found")
	}

	// look for go/types.Object type
	obj := lookupObj(t, goTypesPkg.Scope(), "Object")
	typ, ok := obj.Type().(*types.Named)
	if !ok {
	t.Fatalf("go/types.Object type is %v; wanted named type", typ)
	}

	// lookup go/types.Object.Pkg method
	m, index, indirect := types.LookupFieldOrMethod(typ, false, nil, "Pkg")
	if m == nil {
	t.Fatalf("go/types.Object.Pkg not found (index = %v, indirect = %v)", index, indirect)
	}

	// the method must belong to go/types
	if m.Pkg().Path() != "go/types" {
	t.Fatalf("found %v; want go/types", m.Pkg())
	}
	}

	func TestIssue15517(t *testing.T) {
	skipSpecialPlatforms(t)

	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
	t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
	}

	// On windows, we have to set the -D option for the compiler to avoid having a drive
	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
	if runtime.GOOS == "windows" {
	t.Skip("avoid dealing with relative paths/drive letters on windows")
	}

	tmpdir := mktmpdir(t)
	defer os.RemoveAll(tmpdir)

	compile(t, "testdata", "p.go", filepath.Join(tmpdir, "testdata"))

	// Multiple imports of p must succeed without redeclaration errors.
	// We use an import path that's not cleaned up so that the eventual
	// file path for the package is different from the package path; this
	// will expose the error if it is present.
	//
	// (Issue: Both the textual and the binary importer used the file path
	// of the package to be imported as key into the shared packages map.
	// However, the binary importer then used the package path to identify
	// the imported package to mark it as complete; effectively marking the
	// wrong package as complete. By using an "unclean" package path, the
	// file and package path are different, exposing the problem if present.
	// The same issue occurs with vendoring.)
	imports := make(map[string]*types.Package)
	for i := 0; i < 3; i++ {
	if _, err := Import(imports, "./././testdata/p", tmpdir, nil); err != nil {
	t.Fatal(err)
	}
	}
	}

	func TestIssue15920(t *testing.T) {
	skipSpecialPlatforms(t)

	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
	t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
	}

	// On windows, we have to set the -D option for the compiler to avoid having a drive
	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
	if runtime.GOOS == "windows" {
	t.Skip("avoid dealing with relative paths/drive letters on windows")
	}

	compileAndImportPkg(t, "issue15920")
	}

	func TestIssue20046(t *testing.T) {
	skipSpecialPlatforms(t)

	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
	t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
	}

	// On windows, we have to set the -D option for the compiler to avoid having a drive
	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
	if runtime.GOOS == "windows" {
	t.Skip("avoid dealing with relative paths/drive letters on windows")
	}

	// "./issue20046".V.M must exist
	pkg := compileAndImportPkg(t, "issue20046")
	obj := lookupObj(t, pkg.Scope(), "V")
	if m, index, indirect := types.LookupFieldOrMethod(obj.Type(), false, nil, "M"); m == nil {
	t.Fatalf("V.M not found (index = %v, indirect = %v)", index, indirect)
	}
	}

	func importPkg(t testing.T, path, srcDir string) types.Package {
	pkg, err := Import(make(map[string]*types.Package), path, srcDir, nil)
	if err != nil {
	t.Fatal(err)
	}
	return pkg
	}

	func compileAndImportPkg(t testing.T, name string) types.Package {
	tmpdir := mktmpdir(t)
	defer os.RemoveAll(tmpdir)
	compile(t, "testdata", name+".go", filepath.Join(tmpdir, "testdata"))
	return importPkg(t, "./testdata/"+name, tmpdir)
	}

	func lookupObj(t testing.T, scope types.Scope, name string) types.Object {
	if obj := scope.Lookup(name); obj != nil {
	return obj
	}
	t.Fatalf("%s not found", name)
	return nil
	}