platform_build_blueprint/fs.go
Colin Cross d7b0f60802 Allow tests to mock filesystem
Tests can call Context.MockFileSystem to pass in a map of filenames to
contents.

Change-Id: Idd67c68f7cb43bc2117cc78336347db7e2f21991
2016-08-08 17:26:57 -07:00

73 lines
1.7 KiB
Go

// Copyright 2016 Google Inc. All rights reserved.
//
// 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 blueprint
import (
"bytes"
"io"
"io/ioutil"
"os"
)
// Based on Andrew Gerrand's "10 things you (probably) dont' know about Go"
var fs fileSystem = osFS{}
type fileSystem interface {
Open(name string) (io.ReadCloser, error)
Exists(name string) (bool, bool, error)
}
// osFS implements fileSystem using the local disk.
type osFS struct{}
func (osFS) Open(name string) (io.ReadCloser, error) { return os.Open(name) }
func (osFS) Exists(name string) (bool, bool, error) {
stat, err := os.Stat(name)
if err == nil {
return true, stat.IsDir(), nil
} else if os.IsNotExist(err) {
return false, false, nil
} else {
return false, false, err
}
}
type mockFS struct {
files map[string][]byte
}
func (m mockFS) Open(name string) (io.ReadCloser, error) {
if f, ok := m.files[name]; ok {
return struct {
io.Closer
*bytes.Reader
}{
ioutil.NopCloser(nil),
bytes.NewReader(f),
}, nil
}
return nil, &os.PathError{
Op: "open",
Path: name,
Err: os.ErrNotExist,
}
}
func (m mockFS) Exists(name string) (bool, bool, error) {
_, ok := m.files[name]
return ok, false, nil
}