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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"
8package difftest
9
10import (
11    "testing"
12
13    "golang.org/x/tools/internal/diff"
14)
15
16const (
17    FileA         = "from"
18    FileB         = "to"
19    UnifiedPrefix = "--- " + FileA + "\n+++ " + FileB + "\n"
20)
21
22var TestCases = []struct {
23    Name, In, Out, Unified string
24    Edits, LineEdits       []diff.Edit
25    NoDiff                 bool
26}{{
27    Name: "empty",
28    In:   "",
29    Out:  "",
30}, {
31    Name: "no_diff",
32    In:   "gargantuan\n",
33    Out:  "gargantuan\n",
34}, {
35    Name: "replace_all",
36    In:   "fruit\n",
37    Out:  "cheese\n",
38    Unified: UnifiedPrefix + `
39@@ -1 +1 @@
40-fruit
41+cheese
42`[1:],
43    Edits:     []diff.Edit{{Start: 0, End: 5, New: "cheese"}},
44    LineEdits: []diff.Edit{{Start: 0, End: 6, New: "cheese\n"}},
45}, {
46    Name: "insert_rune",
47    In:   "gord\n",
48    Out:  "gourd\n",
49    Unified: UnifiedPrefix + `
50@@ -1 +1 @@
51-gord
52+gourd
53`[1:],
54    Edits:     []diff.Edit{{Start: 2, End: 2, New: "u"}},
55    LineEdits: []diff.Edit{{Start: 0, End: 5, New: "gourd\n"}},
56}, {
57    Name: "delete_rune",
58    In:   "groat\n",
59    Out:  "goat\n",
60    Unified: UnifiedPrefix + `
61@@ -1 +1 @@
62-groat
63+goat
64`[1:],
65    Edits:     []diff.Edit{{Start: 1, End: 2, New: ""}},
66    LineEdits: []diff.Edit{{Start: 0, End: 6, New: "goat\n"}},
67}, {
68    Name: "replace_rune",
69    In:   "loud\n",
70    Out:  "lord\n",
71    Unified: UnifiedPrefix + `
72@@ -1 +1 @@
73-loud
74+lord
75`[1:],
76    Edits:     []diff.Edit{{Start: 2, End: 3, New: "r"}},
77    LineEdits: []diff.Edit{{Start: 0, End: 5, New: "lord\n"}},
78}, {
79    Name: "replace_partials",
80    In:   "blanket\n",
81    Out:  "bunker\n",
82    Unified: UnifiedPrefix + `
83@@ -1 +1 @@
84-blanket
85+bunker
86`[1:],
87    Edits: []diff.Edit{
88        {Start: 1, End: 3, New: "u"},
89        {Start: 6, End: 7, New: "r"},
90    },
91    LineEdits: []diff.Edit{{Start: 0, End: 8, New: "bunker\n"}},
92}, {
93    Name: "insert_line",
94    In:   "1: one\n3: three\n",
95    Out:  "1: one\n2: two\n3: three\n",
96    Unified: UnifiedPrefix + `
97@@ -1,2 +1,3 @@
98 1: one
99+2: two
100 3: three
101`[1:],
102    Edits: []diff.Edit{{Start: 7, End: 7, New: "2: two\n"}},
103}, {
104    Name: "replace_no_newline",
105    In:   "A",
106    Out:  "B",
107    Unified: UnifiedPrefix + `
108@@ -1 +1 @@
109-A
110\ No newline at end of file
111+B
112\ No newline at end of file
113`[1:],
114    Edits: []diff.Edit{{Start: 0, End: 1, New: "B"}},
115}, {
116    Name: "append_empty",
117    In:   "", // GNU diff -u special case: -0,0
118    Out:  "AB\nC",
119    Unified: UnifiedPrefix + `
120@@ -0,0 +1,2 @@
121+AB
122+C
123\ No newline at end of file
124`[1:],
125    Edits:     []diff.Edit{{Start: 0, End: 0, New: "AB\nC"}},
126    LineEdits: []diff.Edit{{Start: 0, End: 0, New: "AB\nC"}},
127},
128    // TODO(adonovan): fix this test: GNU diff -u prints "+1,2", Unifies prints "+1,3".
129    //     {
130    //         Name: "add_start",
131    //         In:   "A",
132    //         Out:  "B\nCA",
133    //         Unified: UnifiedPrefix + `
134    // @@ -1 +1,2 @@
135    // -A
136    // \ No newline at end of file
137    // +B
138    // +CA
139    // \ No newline at end of file
140    // `[1:],
141    //         Edits:     []diff.TextEdit{{Span: newSpan(0, 0), NewText: "B\nC"}},
142    //         LineEdits: []diff.TextEdit{{Span: newSpan(0, 0), NewText: "B\nC"}},
143    //     },
144    {
145        Name: "add_end",
146        In:   "A",
147        Out:  "AB",
148        Unified: UnifiedPrefix + `
149@@ -1 +1 @@
150-A
151\ No newline at end of file
152+AB
153\ No newline at end of file
154`[1:],
155        Edits:     []diff.Edit{{Start: 1, End: 1, New: "B"}},
156        LineEdits: []diff.Edit{{Start: 0, End: 1, New: "AB"}},
157    }, {
158        Name: "add_empty",
159        In:   "",
160        Out:  "AB\nC",
161        Unified: UnifiedPrefix + `
162@@ -0,0 +1,2 @@
163+AB
164+C
165\ No newline at end of file
166`[1:],
167        Edits:     []diff.Edit{{Start: 0, End: 0, New: "AB\nC"}},
168        LineEdits: []diff.Edit{{Start: 0, End: 0, New: "AB\nC"}},
169    }, {
170        Name: "add_newline",
171        In:   "A",
172        Out:  "A\n",
173        Unified: UnifiedPrefix + `
174@@ -1 +1 @@
175-A
176\ No newline at end of file
177+A
178`[1:],
179        Edits:     []diff.Edit{{Start: 1, End: 1, New: "\n"}},
180        LineEdits: []diff.Edit{{Start: 0, End: 1, New: "A\n"}},
181    }, {
182        Name: "delete_front",
183        In:   "A\nB\nC\nA\nB\nB\nA\n",
184        Out:  "C\nB\nA\nB\nA\nC\n",
185        Unified: UnifiedPrefix + `
186@@ -1,7 +1,6 @@
187-A
188-B
189 C
190+B
191 A
192 B
193-B
194 A
195+C
196`[1:],
197        NoDiff: true, // unified diff is different but valid
198        Edits: []diff.Edit{
199            {Start: 0, End: 4, New: ""},
200            {Start: 6, End: 6, New: "B\n"},
201            {Start: 10, End: 12, New: ""},
202            {Start: 14, End: 14, New: "C\n"},
203        },
204    }, {
205        Name: "replace_last_line",
206        In:   "A\nB\n",
207        Out:  "A\nC\n\n",
208        Unified: UnifiedPrefix + `
209@@ -1,2 +1,3 @@
210 A
211-B
212+C
213+
214`[1:],
215        Edits:     []diff.Edit{{Start: 2, End: 3, New: "C\n"}},
216        LineEdits: []diff.Edit{{Start: 2, End: 4, New: "C\n\n"}},
217    },
218    {
219        Name: "multiple_replace",
220        In:   "A\nB\nC\nD\nE\nF\nG\n",
221        Out:  "A\nH\nI\nJ\nE\nF\nK\n",
222        Unified: UnifiedPrefix + `
223@@ -1,7 +1,7 @@
224 A
225-B
226-C
227-D
228+H
229+I
230+J
231 E
232 F
233-G
234+K
235`[1:],
236        Edits: []diff.Edit{
237            {Start: 2, End: 8, New: "H\nI\nJ\n"},
238            {Start: 12, End: 14, New: "K\n"},
239        },
240        NoDiff: true, // diff algorithm produces different delete/insert pattern
241    },
242}
243
244func DiffTest(t *testing.T, compute func(before, after string) []diff.Edit) {
245    for _, test := range TestCases {
246        t.Run(test.Name, func(t *testing.T) {
247            edits := compute(test.In, test.Out)
248            got, err := diff.Apply(test.In, edits)
249            if err != nil {
250                t.Fatalf("Apply failed: %v", err)
251            }
252            unified, err := diff.ToUnified(FileA, FileB, test.In, edits)
253            if err != nil {
254                t.Fatalf("ToUnified: %v", err)
255            }
256            if got != test.Out {
257                t.Errorf("Apply: got patched:\n%v\nfrom diff:\n%v\nexpected:\n%v", got, unified, test.Out)
258            }
259            if !test.NoDiff && unified != test.Unified {
260                t.Errorf("Unified: got diff:\n%v\nexpected:\n%v", unified, test.Unified)
261            }
262        })
263    }
264}
265
MembersX
DiffTest
DiffTest.t
DiffTest.compute
DiffTest.RangeStmt_5080.test
DiffTest.RangeStmt_5080.BlockStmt.BlockStmt.got
DiffTest.RangeStmt_5080.BlockStmt.BlockStmt.unified
testing
diff
FileA
FileB
DiffTest.RangeStmt_5080.BlockStmt.BlockStmt.edits
DiffTest.RangeStmt_5080.BlockStmt.BlockStmt.err
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