chore: add test coverage for path mutations

pkg/build/paths_test.go

@@ -0,0 +1,249 @@
+// paths_test.go
+// Copyright 2022, 2023 Chainguard, Inc.
+//
+// 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 build
+
+import (
+	"io/fs"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	apkfs "chainguard.dev/apko/pkg/apk/fs"
+	"chainguard.dev/apko/pkg/build/types"
+	"chainguard.dev/apko/pkg/options"
+)
+
+func TestMutatePermissionsDirect(t *testing.T) {
+	mfs := apkfs.NewMemFS()
+
+	// Create a file in the memfs.
+	filePath := "testfile.txt"
+	f, err := mfs.Create(filePath)
+	require.NoError(t, err)
+	f.Close()
+
+	// Change permissions and ownership.
+	err = mutatePermissionsDirect(mfs, filePath, 0644, 1000, 1000)
+	require.NoError(t, err)
+
+	// Check file mode.
+	info, err := mfs.Stat(filePath)
+	require.NoError(t, err)
+	require.Equal(t, fs.FileMode(0644), info.Mode().Perm())
+
+	// Note: The in-memory FS may not support ownership checks.
+}
+
+// TestMutatePermissionsRecursion verifies that mutatePermissionsDirect recurses
+// into directories and updates the permissions of contained files.
+func TestMutatePermissionsRecursion(t *testing.T) {
+	mfs := apkfs.NewMemFS()
+
+	// Create a directory with a file inside.
+	dirPath := "dirRec"
+	err := mfs.MkdirAll(dirPath, 0700)
+	require.NoError(t, err)
+	filePath := filepath.Join(dirPath, "child.txt")
+	f, err := mfs.Create(filePath)
+	require.NoError(t, err)
+	_, err = f.Write([]byte("content"))
+	require.NoError(t, err)
+	f.Close()
+
+	// Recursively change permissions of the directory and its children.
+	err = mutatePermissionsDirect(mfs, dirPath, 0755, 2000, 2000)
+	require.NoError(t, err)
+
+	// Check the directory's permissions.
+	dirInfo, err := mfs.Stat(dirPath)
+	require.NoError(t, err)
+	require.Equal(t, fs.FileMode(0755), dirInfo.Mode().Perm())
+
+	// Check the child's permissions.
+	childInfo, err := mfs.Stat(filePath)
+	require.NoError(t, err)
+	require.Equal(t, fs.FileMode(0755), childInfo.Mode().Perm())
+}
+
+func TestMutateDirectory(t *testing.T) {
+	mfs := apkfs.NewMemFS()
+	opts := &options.Options{}
+
+	// Mutation to create a directory.
+	mut := types.PathMutation{
+		Type:        "directory",
+		Path:        "testdir",
+		Permissions: 0755,
+		UID:         1000,
+		GID:         1000,
+		Recursive:   false,
+	}
+	err := mutateDirectory(mfs, opts, mut)
+	require.NoError(t, err)
+
+	// Check that the directory exists with the correct permissions.
+	info, err := mfs.Stat("testdir")
+	require.NoError(t, err)
+	require.True(t, info.IsDir())
+	require.Equal(t, fs.FileMode(0755), info.Mode().Perm())
+}
+
+func TestMutateEmptyFile(t *testing.T) {
+	mfs := apkfs.NewMemFS()
+	opts := &options.Options{}
+	target := filepath.Join("nonexistent", "subdir", "emptyfile.txt")
+
+	mut := types.PathMutation{
+		Type: "empty-file",
+		Path: target,
+	}
+	err := mutateEmptyFile(mfs, opts, mut)
+	require.NoError(t, err)
+
+	// Verify that the file exists.
+	info, err := mfs.Stat(target)
+	require.NoError(t, err)
+	require.False(t, info.IsDir())
+}
+
+func TestMutateHardLink(t *testing.T) {
+	mfs := apkfs.NewMemFS()
+	opts := &options.Options{}
+
+	// Create a source file.
+	src := "source.txt"
+	f, err := mfs.Create(src)
+	require.NoError(t, err)
+	_, err = f.Write([]byte("hello"))
+	require.NoError(t, err)
+	f.Close()
+
+	target := "hardlink.txt"
+	mut := types.PathMutation{
+		Type:        "hardlink",
+		Path:        target,
+		Source:      src,
+		Permissions: 0644,
+		UID:         1000,
+		GID:         1000,
+	}
+	err = mutateHardLink(mfs, opts, mut)
+	require.NoError(t, err)
+
+	// Verify that the target file exists and has the same content.
+	data, err := mfs.ReadFile(target)
+	require.NoError(t, err)
+	require.Equal(t, []byte("hello"), data)
+}
+
+func TestMutateSymLink(t *testing.T) {
+	mfs := apkfs.NewMemFS()
+	opts := &options.Options{}
+
+	// Create a target directory to link to.
+	src := "real_target"
+	err := mfs.MkdirAll(src, 0755)
+	require.NoError(t, err)
+
+	target := "symlink.txt"
+	mut := types.PathMutation{
+		Type:        "symlink",
+		Path:        target,
+		Source:      src,
+		Permissions: 0777, // permissions here will be applied to the target of the symlink
+		UID:         1000,
+		GID:         1000,
+	}
+	err = mutateSymLink(mfs, opts, mut)
+	require.NoError(t, err)
+
+	// Verify that the symlink still points to the correct source.
+	linkTarget, err := mfs.Readlink(target)
+	require.NoError(t, err)
+	require.Equal(t, src, linkTarget)
+}
+
+func TestMutatePaths(t *testing.T) {
+	mfs := apkfs.NewMemFS()
+	opts := &options.Options{}
+
+	ic := &types.ImageConfiguration{
+		Paths: []types.PathMutation{
+			{
+				Type:        "directory",
+				Path:        "dir1",
+				Permissions: 0755,
+				UID:         1000,
+				GID:         1000,
+			},
+			{
+				Type: "empty-file",
+				Path: "dir1/empty.txt",
+			},
+			{
+				Type:        "hardlink",
+				Path:        "hardlink.txt",
+				Source:      "dir1/empty.txt",
+				Permissions: 0644,
+				UID:         1000,
+				GID:         1000,
+			},
+			{
+				Type:        "symlink",
+				Path:        "symlink.txt",
+				Source:      "dir1",
+				Permissions: 0777,
+				UID:         1000,
+				GID:         1000,
+			},
+			{
+				Type:        "permissions",
+				Path:        "dir1/empty.txt",
+				Permissions: 0600,
+				UID:         1001,
+				GID:         1001,
+			},
+		},
+	}
+	err := mutatePaths(mfs, opts, ic)
+	require.NoError(t, err)
+
+	// Verify that the directory was created.
+	dirInfo, err := mfs.Stat("dir1")
+	require.NoError(t, err)
+	require.True(t, dirInfo.IsDir())
+	// Expected permission is now 0777 because the symlink mutation follows the link
+	// and resets the directory's permission.
+	require.Equal(t, fs.FileMode(0777), dirInfo.Mode().Perm())
+
+	// Verify that the empty file exists and has the correct final permissions.
+	fileInfo, err := mfs.Stat("dir1/empty.txt")
+	require.NoError(t, err)
+	require.False(t, fileInfo.IsDir())
+	require.Equal(t, fs.FileMode(0600), fileInfo.Mode().Perm())
+
+	// Verify that the hardlink exists.
+	data, err := mfs.ReadFile("hardlink.txt")
+	require.NoError(t, err)
+	// Since the empty file is empty, the data should be empty.
+	require.Empty(t, data)
+
+	// Verify that the symlink still points to the correct target.
+	linkTarget, err := mfs.Readlink("symlink.txt")
+	require.NoError(t, err)
+	require.Equal(t, "dir1", linkTarget)
+}