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// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package compare
import (
"bytes"
"golang.org/x/tools/internal/diff"
)
// Text returns a formatted unified diff of the edits to go from want to
// got, returning "" if and only if want == got.
//
// This function is intended for use in testing, and panics if any error occurs
// while computing the diff. It is not sufficiently tested for production use.
func Text(want, got string) string {
return NamedText("want", "got", want, got)
}
// NamedText is like text, but allows passing custom names of the 'want' and
// 'got' content.
func NamedText(wantName, gotName, want, got string) string {
if want == got {
return ""
}
// Add newlines to avoid verbose newline messages ("No newline at end of file").
unified := diff.Unified(wantName, gotName, want+"\n", got+"\n")
// Defensively assert that we get an actual diff, so that we guarantee the
// invariant that we return "" if and only if want == got.
//
// This is probably unnecessary, but convenient.
if unified == "" {
panic("empty diff for non-identical input")
}
return unified
}
// Bytes is like Text but using byte slices.
func Bytes(want, got []byte) string {
if bytes.Equal(want, got) {
return "" // common case
}
return Text(string(want), string(got))
}
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