fork of go-gitdiff with jj support
oppi.li
1package gitdiff
2
3import (
4 "bytes"
5 "fmt"
6 "io"
7 "testing"
8)
9
10func TestLineReaderAt(t *testing.T) {
11 tests := map[string]struct {
12 InputLines int
13 Offset int64
14 Count int
15 Err bool
16 EOF bool
17 EOFCount int
18 }{
19 "readLines": {
20 InputLines: 32,
21 Offset: 0,
22 Count: 4,
23 },
24 "readLinesOffset": {
25 InputLines: 32,
26 Offset: 8,
27 Count: 4,
28 },
29 "readLinesLargeOffset": {
30 InputLines: 8192,
31 Offset: 4096,
32 Count: 64,
33 },
34 "readSingleLine": {
35 InputLines: 4,
36 Offset: 2,
37 Count: 1,
38 },
39 "readZeroLines": {
40 InputLines: 4,
41 Offset: 2,
42 Count: 0,
43 },
44 "readThroughEOF": {
45 InputLines: 16,
46 Offset: 12,
47 Count: 8,
48 EOF: true,
49 EOFCount: 4,
50 },
51 "emptyInput": {
52 InputLines: 0,
53 Offset: 0,
54 Count: 2,
55 EOF: true,
56 EOFCount: 0,
57 },
58 "offsetAfterEOF": {
59 InputLines: 8,
60 Offset: 10,
61 Count: 2,
62 EOF: true,
63 EOFCount: 0,
64 },
65 "offsetNegative": {
66 InputLines: 8,
67 Offset: -1,
68 Count: 2,
69 Err: true,
70 },
71 }
72
73 const lineTemplate = "generated test line %d\n"
74
75 for name, test := range tests {
76 t.Run(name, func(t *testing.T) {
77 var input bytes.Buffer
78 for i := 0; i < test.InputLines; i++ {
79 fmt.Fprintf(&input, lineTemplate, i)
80 }
81
82 output := make([][]byte, test.Count)
83 for i := 0; i < test.Count; i++ {
84 output[i] = []byte(fmt.Sprintf(lineTemplate, test.Offset+int64(i)))
85 }
86
87 r := &lineReaderAt{r: bytes.NewReader(input.Bytes())}
88 lines := make([][]byte, test.Count)
89
90 n, err := r.ReadLinesAt(lines, test.Offset)
91 if test.Err {
92 if err == nil {
93 t.Fatal("expected error reading lines, but got nil")
94 }
95 return
96 }
97 if err != nil && (!test.EOF || err != io.EOF) {
98 t.Fatalf("unexpected error reading lines: %v", err)
99 }
100
101 count := test.Count
102 if test.EOF {
103 count = test.EOFCount
104 }
105
106 if n != count {
107 t.Fatalf("incorrect number of lines read: expected %d, actual %d", count, n)
108 }
109 for i := 0; i < n; i++ {
110 if !bytes.Equal(output[i], lines[i]) {
111 t.Errorf("incorrect content in line %d:\nexpected: %q\nactual: %q", i, output[i], lines[i])
112 }
113 }
114 })
115 }
116}