common/testing/testfs/build.go

// Copyright 2017 The LUCI Authors.
//
// 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 testfs

import (
	"io/ioutil"
	"path/filepath"
	"sort"
	"strings"

	"go.chromium.org/luci/common/system/filesystem"
)

// Build constructs a filesystem hierarchy given a layout.
//
// The layouts keys should be ToSlash-style file paths. Its values should be the
// content that is written at those paths. Intermediate directories will be
// automatically created.
//
// To create a directory, end its path with a "/". In this case, the content
// will be ignored.
func Build(base string, layout map[string]string) error {
	keys := make([]string, 0, len(layout))
	for k := range layout {
		keys = append(keys, k)
	}
	sort.Strings(keys)

	for _, path := range keys {
		makeDir := strings.HasSuffix(path, "/")
		content := layout[path]

		// Normalize "path" to the current OS.
		path = filepath.Join(base, filepath.FromSlash(path))

		if makeDir {
			// Make a directory.
			if err := filesystem.MakeDirs(path); err != nil {
				return err
			}
		} else {
			// Make a file.

			if err := filesystem.MakeDirs(filepath.Dir(path)); err != nil {
				return err
			}
			if err := ioutil.WriteFile(path, []byte(content), 0644); err != nil {
				return err
			}
		}
	}
	return nil
}