Update diff apply test to check sub directories

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
(cherry picked from commit 5c05b8447d06793530e3d860b99a6e878685275a)
Signed-off-by: Tibor Vass <tibor@docker.com>

daemon/graphdriver/graphtest/graphtest_unix.go

@@ -199,6 +199,7 @@ func DriverTestDiffApply(t testing.TB, fileCount int, drivername string, driverO
 	upper := stringid.GenerateRandomID()
 	deleteFile := "file-remove.txt"
 	deleteFileContent := []byte("This file should get removed in upper!")
+	deleteDir := "var/lib"
 
 	if err := driver.Create(base, "", "", nil); err != nil {
 		t.Fatal(err)
@@ -212,6 +213,10 @@ func DriverTestDiffApply(t testing.TB, fileCount int, drivername string, driverO
 		t.Fatal(err)
 	}
 
+	if err := addDirectory(driver, base, deleteDir); err != nil {
+		t.Fatal(err)
+	}
+
 	if err := driver.Create(upper, base, "", nil); err != nil {
 		t.Fatal(err)
 	}
@@ -220,7 +225,7 @@ func DriverTestDiffApply(t testing.TB, fileCount int, drivername string, driverO
 		t.Fatal(err)
 	}
 
-	if err := removeFile(driver, upper, deleteFile); err != nil {
+	if err := removeAll(driver, upper, deleteFile, deleteDir); err != nil {
 		t.Fatal(err)
 	}
 
@@ -271,6 +276,10 @@ func DriverTestDiffApply(t testing.TB, fileCount int, drivername string, driverO
 	if err := checkFileRemoved(driver, diff, deleteFile); err != nil {
 		t.Fatal(err)
 	}
+
+	if err := checkFileRemoved(driver, diff, deleteDir); err != nil {
+		t.Fatal(err)
+	}
 }
 
 // DriverTestChanges tests computed changes on a layer matches changes made

daemon/graphdriver/graphtest/testutil.go

@@ -78,14 +78,29 @@ func addFile(drv graphdriver.Driver, layer, filename string, content []byte) err
 	return ioutil.WriteFile(path.Join(root, filename), content, 0755)
 }
 
-func removeFile(drv graphdriver.Driver, layer, filename string) error {
+func addDirectory(drv graphdriver.Driver, layer, dir string) error {
 	root, err := drv.Get(layer, "")
 	if err != nil {
 		return err
 	}
 	defer drv.Put(layer)
 
-	return os.Remove(path.Join(root, filename))
+	return os.MkdirAll(path.Join(root, dir), 0755)
+}
+
+func removeAll(drv graphdriver.Driver, layer string, names ...string) error {
+	root, err := drv.Get(layer, "")
+	if err != nil {
+		return err
+	}
+	defer drv.Put(layer)
+
+	for _, filename := range names {
+		if err := os.RemoveAll(path.Join(root, filename)); err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func checkFileRemoved(drv graphdriver.Driver, layer, filename string) error {