| // 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 ( |
| "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 { |
| if want == got { |
| return "" |
| } |
| |
| // Add newlines to avoid verbose newline messages ("No newline at end of file"). |
| unified := diff.Unified("want", "got", 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 |
| } |
