1// Copyright 2015 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
5package exec
6
7import (
8	"io"
9	"testing"
10)
11
12func TestPrefixSuffixSaver(t *testing.T) {
13	tests := []struct {
14		N      int
15		writes []string
16		want   string
17	}{
18		{
19			N:      2,
20			writes: nil,
21			want:   "",
22		},
23		{
24			N:      2,
25			writes: []string{"a"},
26			want:   "a",
27		},
28		{
29			N:      2,
30			writes: []string{"abc", "d"},
31			want:   "abcd",
32		},
33		{
34			N:      2,
35			writes: []string{"abc", "d", "e"},
36			want:   "ab\n... omitting 1 bytes ...\nde",
37		},
38		{
39			N:      2,
40			writes: []string{"ab______________________yz"},
41			want:   "ab\n... omitting 22 bytes ...\nyz",
42		},
43		{
44			N:      2,
45			writes: []string{"ab_______________________y", "z"},
46			want:   "ab\n... omitting 23 bytes ...\nyz",
47		},
48	}
49	for i, tt := range tests {
50		w := &prefixSuffixSaver{N: tt.N}
51		for _, s := range tt.writes {
52			n, err := io.WriteString(w, s)
53			if err != nil || n != len(s) {
54				t.Errorf("%d. WriteString(%q) = %v, %v; want %v, %v", i, s, n, err, len(s), nil)
55			}
56		}
57		if got := string(w.Bytes()); got != tt.want {
58			t.Errorf("%d. Bytes = %q; want %q", i, got, tt.want)
59		}
60	}
61}
62