os: don't create files in local directory

Also, use a random temporary directory rather than os.TempDir.  Defer
removal of existing random temporary directories.

Change-Id: Id7549031cdf78a2bab28c07b6eeff621bdf6e49c
Reviewed-on: https://go-review.googlesource.com/c/146457
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>

src/os/removeall_test.go

@@ -8,18 +8,23 @@ import (
 	"fmt"
 	"io/ioutil"
 	. "os"
+	"path/filepath"
 	"runtime"
 	"strings"
 	"testing"
 )
 
 func TestRemoveAll(t *testing.T) {
-	tmpDir := TempDir()
-	// Work directory.
-	file := "file"
-	path := tmpDir + "/_TestRemoveAll_"
-	fpath := path + "/file"
-	dpath := path + "/dir"
+	tmpDir, err := ioutil.TempDir("", "TestRemoveAll-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(tmpDir)
+
+	file := filepath.Join(tmpDir, "file")
+	path := filepath.Join(tmpDir, "_TestRemoveAll_")
+	fpath := filepath.Join(path, "file")
+	dpath := filepath.Join(path, "dir")
 
 	// Make a regular file and remove
 	fd, err := Create(file)
@@ -127,9 +132,13 @@ func TestRemoveAllLarge(t *testing.T) {
 		t.Skip("skipping in short mode")
 	}
 
-	tmpDir := TempDir()
-	// Work directory.
-	path := tmpDir + "/_TestRemoveAllLarge_"
+	tmpDir, err := ioutil.TempDir("", "TestRemoveAll-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(tmpDir)
+
+	path := filepath.Join(tmpDir, "_TestRemoveAllLarge_")
 
 	// Make directory with 1000 files and remove.
 	if err := MkdirAll(path, 0777); err != nil {
@@ -168,6 +177,8 @@ func TestRemoveAllLongPath(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Could not create TempDir: %s", err)
 	}
+	defer RemoveAll(startPath)
+
 	err = Chdir(startPath)
 	if err != nil {
 		t.Fatalf("Could not chdir %s: %s", startPath, err)
@@ -215,6 +226,8 @@ func TestRemoveAllDot(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Could not create TempDir: %s", err)
 	}
+	defer RemoveAll(tempDir)
+
 	err = Chdir(tempDir)
 	if err != nil {
 		t.Fatalf("Could not chdir to tempdir: %s", err)