| 1 | // Copyright 2019 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // Package difftest supplies a set of tests that will operate on any |
| 6 | // implementation of a diff algorithm as exposed by |
| 7 | // "golang.org/x/tools/internal/diff" |
| 8 | package difftest_test |
| 9 | |
| 10 | import ( |
| 11 | "fmt" |
| 12 | "io/ioutil" |
| 13 | "os" |
| 14 | "os/exec" |
| 15 | "strings" |
| 16 | "testing" |
| 17 | |
| 18 | "golang.org/x/tools/internal/diff/difftest" |
| 19 | "golang.org/x/tools/internal/testenv" |
| 20 | ) |
| 21 | |
| 22 | func TestVerifyUnified(t *testing.T) { |
| 23 | testenv.NeedsTool(t, "diff") |
| 24 | for _, test := range difftest.TestCases { |
| 25 | t.Run(test.Name, func(t *testing.T) { |
| 26 | if test.NoDiff { |
| 27 | t.Skip("diff tool produces expected different results") |
| 28 | } |
| 29 | diff, err := getDiffOutput(test.In, test.Out) |
| 30 | if err != nil { |
| 31 | t.Fatal(err) |
| 32 | } |
| 33 | if len(diff) > 0 { |
| 34 | diff = difftest.UnifiedPrefix + diff |
| 35 | } |
| 36 | if diff != test.Unified { |
| 37 | t.Errorf("unified:\n%s\ndiff -u:\n%s", test.Unified, diff) |
| 38 | } |
| 39 | }) |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | func getDiffOutput(a, b string) (string, error) { |
| 44 | fileA, err := ioutil.TempFile("", "myers.in") |
| 45 | if err != nil { |
| 46 | return "", err |
| 47 | } |
| 48 | defer os.Remove(fileA.Name()) |
| 49 | if _, err := fileA.Write([]byte(a)); err != nil { |
| 50 | return "", err |
| 51 | } |
| 52 | if err := fileA.Close(); err != nil { |
| 53 | return "", err |
| 54 | } |
| 55 | fileB, err := ioutil.TempFile("", "myers.in") |
| 56 | if err != nil { |
| 57 | return "", err |
| 58 | } |
| 59 | defer os.Remove(fileB.Name()) |
| 60 | if _, err := fileB.Write([]byte(b)); err != nil { |
| 61 | return "", err |
| 62 | } |
| 63 | if err := fileB.Close(); err != nil { |
| 64 | return "", err |
| 65 | } |
| 66 | cmd := exec.Command("diff", "-u", fileA.Name(), fileB.Name()) |
| 67 | cmd.Env = append(cmd.Env, "LANG=en_US.UTF-8") |
| 68 | out, err := cmd.CombinedOutput() |
| 69 | if err != nil { |
| 70 | if _, ok := err.(*exec.ExitError); !ok { |
| 71 | return "", fmt.Errorf("failed to run diff -u %v %v: %v\n%v", fileA.Name(), fileB.Name(), err, string(out)) |
| 72 | } |
| 73 | } |
| 74 | diff := string(out) |
| 75 | if len(diff) <= 0 { |
| 76 | return diff, nil |
| 77 | } |
| 78 | bits := strings.SplitN(diff, "\n", 3) |
| 79 | if len(bits) != 3 { |
| 80 | return "", fmt.Errorf("diff output did not have file prefix:\n%s", diff) |
| 81 | } |
| 82 | return bits[2], nil |
| 83 | } |
| 84 |
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