misc/cgo/life: fix tests in module mode

Updates #30228

Change-Id: Ie972694254d2195ca9760ea7ffb6073e01c52488
Reviewed-on: https://go-review.googlesource.com/c/163422
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

misc/cgo/life/life_test.go

+// 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 life_test
+
+import (
+	"bytes"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestMain(m *testing.M) {
+	log.SetFlags(log.Lshortfile)
+	os.Exit(testMain(m))
+}
+
+func testMain(m *testing.M) int {
+	GOPATH, err := ioutil.TempDir("", "cgolife")
+	if err != nil {
+		log.Panic(err)
+	}
+	defer os.RemoveAll(GOPATH)
+	os.Setenv("GOPATH", GOPATH)
+
+	// Copy testdata into GOPATH/src/cgolife, along with a go.mod file
+	// declaring the same path.
+	modRoot := filepath.Join(GOPATH, "src", "cgolife")
+	if err := overlayDir(modRoot, "testdata"); err != nil {
+		log.Panic(err)
+	}
+	if err := os.Chdir(modRoot); err != nil {
+		log.Panic(err)
+	}
+	if err := ioutil.WriteFile("go.mod", []byte("module cgolife\n"), 0666); err != nil {
+		log.Panic(err)
+	}
+
+	return m.Run()
+}
+
+func TestTestRun(t *testing.T) {
+	out, err := exec.Command("go", "env", "GOROOT").Output()
+	if err != nil {
+		t.Fatal(err)
+	}
+	GOROOT := string(bytes.TrimSpace(out))
+
+	cmd := exec.Command("go", "run", filepath.Join(GOROOT, "test", "run.go"), "-", ".")
+	out, err = cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("%s: %s\n%s", strings.Join(cmd.Args, " "), err, out)
+	}
+	t.Logf("%s:\n%s", strings.Join(cmd.Args, " "), out)
+}

misc/cgo/life/overlaydir_test.go

+// 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 life_test
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// overlayDir makes a minimal-overhead copy of srcRoot in which new files may be added.
+//
+// TODO: Once we no longer need to support the misc module in GOPATH mode,
+// factor this function out into a package to reduce duplication.
+func overlayDir(dstRoot, srcRoot string) error {
+	dstRoot = filepath.Clean(dstRoot)
+	if err := os.MkdirAll(dstRoot, 0777); err != nil {
+		return err
+	}
+
+	symBase, err := filepath.Rel(srcRoot, dstRoot)
+	if err != nil {
+		symBase, err = filepath.Abs(srcRoot)
+		if err != nil {
+			return err
+		}
+	}
+
+	return filepath.Walk(srcRoot, func(srcPath string, info os.FileInfo, err error) error {
+		if err != nil || srcPath == srcRoot {
+			return err
+		}
+
+		suffix := strings.TrimPrefix(srcPath, srcRoot)
+		for len(suffix) > 0 && suffix[0] == filepath.Separator {
+			suffix = suffix[1:]
+		}
+		dstPath := filepath.Join(dstRoot, suffix)
+
+		perm := info.Mode() & os.ModePerm
+		if info.Mode()&os.ModeSymlink != 0 {
+			info, err = os.Stat(srcPath)
+			if err != nil {
+				return err
+			}
+			perm = info.Mode() & os.ModePerm
+		}
+
+		// Always copy directories (don't symlink them).
+		// If we add a file in the overlay, we don't want to add it in the original.
+		if info.IsDir() {
+			return os.Mkdir(dstPath, perm)
+		}
+
+		// If the OS supports symlinks, use them instead of copying bytes.
+		if err := os.Symlink(filepath.Join(symBase, suffix), dstPath); err == nil {
+			return nil
+		}
+
+		// Otherwise, copy the bytes.
+		src, err := os.Open(srcPath)
+		if err != nil {
+			return err
+		}
+		defer src.Close()
+
+		dst, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE|os.O_EXCL, perm)
+		if err != nil {
+			return err
+		}
+
+		_, err = io.Copy(dst, src)
+		if closeErr := dst.Close(); err == nil {
+			err = closeErr
+		}
+		return err
+	})
+}

misc/cgo/life/life.go → misc/cgo/life/testdata/life.go

@@ -4,7 +4,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package life
+package cgolife
 
 // #include "life.h"
 import "C"

misc/cgo/life/main.go → misc/cgo/life/testdata/main.go

@@ -14,7 +14,7 @@ import (
 	"flag"
 	"fmt"
 
-	"."
+	"cgolife"
 )
 
 const MAXDIM = 100
@@ -34,7 +34,7 @@ func main() {
 		}
 	}
 
-	life.Run(*gen, *dim, *dim, a[:])
+	cgolife.Run(*gen, *dim, *dim, a[:])
 
 	for i := 0; i < *dim; i++ {
 		for j := 0; j < *dim; j++ {

src/cmd/dist/test.go

@@ -619,7 +619,7 @@ func (t *tester) registerTests() {
 			name:    "cgo_life",
 			heading: "../misc/cgo/life",
 			fn: func(dt *distTest) error {
-				t.addCmd(dt, "misc/cgo/life", "go", "run", filepath.Join(os.Getenv("GOROOT"), "test/run.go"), "-", ".")
+				t.addCmd(dt, "misc/cgo/life", t.goTest(), t.timeout(120))
 				return nil
 			},
 		})