code review 1103041: os: add Utime function

src/pkg/os/os_test.go

 // Copyright 2009 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 os_test
 
 import (
         "bytes"
         "fmt"
         "io"
@@ skipping 465 matching lines @@
         fd.Truncate(1024)
         checkSize(t, Path, 1024)
         fd.Truncate(0)
         checkSize(t, Path, 0)
         fd.Write([]byte("surprise!"))
         checkSize(t, Path, 13+9) // wrote at offset past where hello, world was.
         fd.Close()
         Remove(Path)
 }
 
-func TestUtime(t *testing.T) {
+func TestChtimes(t *testing.T) {
         MkdirAll("_obj", 0777)
-        const Path = "_obj/_TestUtime_"
+        const Path = "_obj/_TestChtimes_"
         fd, err := Open(Path, O_WRONLY|O_CREAT, 0666)
         if err != nil {
                 t.Fatalf("create %s: %s", Path, err)
         }
         fd.Write([]byte("hello, world\n"))
         fd.Close()
 
         preStat, err := Stat(Path)
         if err != nil {
-                t.Fatalf("stat %s: %s", Path, err)
+                t.Fatalf("Stat %s: %s", Path, err)
         }
 
         // Move access and modification time back a second
-        const SecondNanos = 1000000000
-        err = Utime(Path, preStat.Atime_ns-SecondNanos, preStat.Mtime_ns-SecondNanos)
-        if err != nil {
-                t.Fatalf("utime %s: %s", Path, err)
+        const OneSecond = 1e9 // in nanoseconds
+        err = Chtimes(Path, preStat.Atime_ns-OneSecond, preStat.Mtime_ns-OneSecond)
+        if err != nil {
+                t.Fatalf("Chtimes %s: %s", Path, err)
         }
 
         postStat, err := Stat(Path)
         if err != nil {
-                t.Fatalf("second stat %s: %s", Path, err)
+                t.Fatalf("second Stat %s: %s", Path, err)
         }
 
         if postStat.Atime_ns >= preStat.Atime_ns {
                 t.Errorf("Atime_ns didn't go backwards; was=%d, after=%d",
                         preStat.Atime_ns,
                         postStat.Atime_ns)
         }
 
         if postStat.Mtime_ns >= preStat.Mtime_ns {
                 t.Errorf("Mtime_ns didn't go backwards; was=%d, after=%d",
@@ skipping 216 matching lines @@
         }
 
         b, err := ioutil.ReadFile("_obj/writetest")
         if err != nil {
                 t.Fatalf("ReadFile _obj/writetest: %v", err)
         }
         if string(b) != "hello, WORLD\n" {
                 t.Fatalf("after write: have %q want %q", string(b), "hello, WORLD\n")
         }
 }