// Copyright 2017 Google 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 testutil

import "github.com/pmezard/go-difflib/difflib"

// GenerateUnifiedDiff takes two strings and generates a diff that can be
// shown to the user in a test error message.
func GenerateUnifiedDiff(want, got string) (string, error) {
	diffl := difflib.UnifiedDiff{
		A:        difflib.SplitLines(want),
		B:        difflib.SplitLines(got),
		FromFile: "want",
		ToFile:   "got",
		Context:  3,
		Eol:      "\n",
	}
	return difflib.GetUnifiedDiffString(diffl)
}
