Fixed file modified time not changing on Windows

Signed-off-by: Darren Stahl <darst@microsoft.com>

system/utimes_unix_test.go

@@ -0,0 +1,68 @@
+// +build linux freebsd
+
+package system
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"syscall"
+	"testing"
+)
+
+// prepareFiles creates files for testing in the temp directory
+func prepareFiles(t *testing.T) (string, string, string, string) {
+	dir, err := ioutil.TempDir("", "docker-system-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	file := filepath.Join(dir, "exist")
+	if err := ioutil.WriteFile(file, []byte("hello"), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	invalid := filepath.Join(dir, "doesnt-exist")
+
+	symlink := filepath.Join(dir, "symlink")
+	if err := os.Symlink(file, symlink); err != nil {
+		t.Fatal(err)
+	}
+
+	return file, invalid, symlink, dir
+}
+
+func TestLUtimesNano(t *testing.T) {
+	file, invalid, symlink, dir := prepareFiles(t)
+	defer os.RemoveAll(dir)
+
+	before, err := os.Stat(file)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ts := []syscall.Timespec{{0, 0}, {0, 0}}
+	if err := LUtimesNano(symlink, ts); err != nil {
+		t.Fatal(err)
+	}
+
+	symlinkInfo, err := os.Lstat(symlink)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if before.ModTime().Unix() == symlinkInfo.ModTime().Unix() {
+		t.Fatal("The modification time of the symlink should be different")
+	}
+
+	fileInfo, err := os.Stat(file)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if before.ModTime().Unix() != fileInfo.ModTime().Unix() {
+		t.Fatal("The modification time of the file should be same")
+	}
+
+	if err := LUtimesNano(invalid, ts); err == nil {
+		t.Fatal("Doesn't return an error on a non-existing file")
+	}
+}