Add create layer test

Signed-off-by: Lei Jitang <leijitang@huawei.com>

image/layer_test.go

@@ -0,0 +1,211 @@
+// Copyright 2016 The Linux Foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package image
+
+import (
+	"archive/tar"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestCreateFilesystemChangeset(t *testing.T) {
+	// create base fileystem
+	tmp1, err := ioutil.TempDir("", "test-layer")
+	if err != nil {
+		t.Fatal(err)
+	}
+	//defer os.RemoveAll(tmp1)
+	basepath := filepath.Join(tmp1, "base")
+	err = os.MkdirAll(basepath, 0700)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// get the file list of base layer
+	expectedFiles := map[string]bool{
+		"bin/":                    true,
+		"bin/app":                 true,
+		"bin/test":                true,
+		"bin/tool":                true,
+		"etc/":                    true,
+		"etc/app.cfg":             true,
+		"etc/tool.cfg.d/":         true,
+		"etc/tool.cfg.d/tool.cfg": true,
+	}
+	err = createFilesystem(basepath, expectedFiles, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// create base layer
+	tarfile := filepath.Join(tmp1, "base.tar")
+	err = CreateLayer(basepath, "", tarfile)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	files, err := listTarFiles(tarfile)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// verify base layer has packed all the file
+	// and no expected file are packed.
+	err = verify(expectedFiles, files)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// create a identical copy of base
+	snapshot1path := filepath.Join(tmp1, "base.s1")
+	cpCmd := exec.Command("cp", "-a", basepath, snapshot1path)
+	err = cpCmd.Run()
+	if err != nil {
+		t.Fatalf("fail to cp: %v", err)
+	}
+
+	// delete some file and add some file in base.s1
+	layer1FilesDiff := map[string]bool{
+		"bin/tool":              false,
+		"bin/app.tool":          true,
+		"etc/app.cfg":           false,
+		"etc/tool.cfg.d/":       false,
+		"etc/app.cfg.d/":        true,
+		"etc/app.tool.cfg":      true,
+		"etc/app.cfg.d/app.cfg": true,
+	}
+	modifiedfiles := map[string]func(string) error{
+		"bin/app": func(path string) error {
+			err := ioutil.WriteFile(path, []byte(fmt.Sprintf("Hello world")), 0755)
+			return err
+		},
+	}
+
+	err = createFilesystem(snapshot1path, layer1FilesDiff, modifiedfiles)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// create layer diff
+	tarfile1 := filepath.Join(tmp1, "base.s1.tar")
+	err = CreateLayer(snapshot1path, basepath, tarfile1)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	execptedfiles := map[string]bool{
+		"bin/":                  true,
+		"bin/app":               true,
+		"bin/app.tool":          true,
+		"bin/.wh.tool":          true,
+		"etc/":                  true,
+		"etc/.wh.app.cfg":       true,
+		"etc/app.cfg.d/":        true,
+		"etc/app.cfg.d/app.cfg": true,
+		"etc/app.tool.cfg":      true,
+		"etc/.wh.tool.cfg.d":    true,
+	}
+
+	actualfile, err := listTarFiles(tarfile1)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// verify if CreateLayer has created expected filesystem changeset
+	err = verify(execptedfiles, actualfile)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func createFilesystem(path string, files map[string]bool, modify map[string]func(string) error) error {
+	for f, add := range files {
+		// add file
+		if add {
+			// create a directory
+			if strings.HasSuffix(f, "/") {
+				err := os.MkdirAll(filepath.Join(path, f), 0700)
+				if err != nil {
+					return err
+				}
+			} else { // create file
+				file := filepath.Join(path, f)
+				err := os.MkdirAll(filepath.Dir(file), 0700)
+				if err != nil {
+					return err
+				}
+				_, err = os.Create(file)
+				if err != nil {
+					return err
+				}
+			}
+		} else { // remove file
+			file := filepath.Join(path, f)
+			err := os.RemoveAll(file)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	// apply file modify
+	for f, fun := range modify {
+		err := fun(filepath.Join(path, f))
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func verify(m1 map[string]bool, m2 map[string]bool) error {
+	for f, _ := range m1 {
+		if _, ok := m2[f]; !ok {
+			return fmt.Errorf("expected file %v not exist", f)
+		}
+	}
+
+	for f, _ := range m2 {
+		if _, ok := m1[f]; !ok {
+			return fmt.Errorf("%v is not an expected file", f)
+		}
+	}
+	return nil
+}
+
+func listTarFiles(path string) (map[string]bool, error) {
+	var files = make(map[string]bool)
+	file, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+
+	tr := tar.NewReader(file)
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, err
+		}
+		files[hdr.Name] = true
+	}
+	return files, nil
+}