test: DRY out MockFilesystem

datasource/test/test.go

@@ -0,0 +1,28 @@
+// Copyright 2015 CoreOS, 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 test
+
+import (
+	"os"
+)
+
+type MockFilesystem map[string]string
+
+func (m MockFilesystem) ReadFile(filename string) ([]byte, error) {
+	if contents, ok := m[filename]; ok {
+		return []byte(contents), nil
+	}
+	return nil, os.ErrNotExist
+}