| 1 | // Copyright 2022 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 lcs |
| 6 | |
| 7 | import ( |
| 8 | "log" |
| 9 | "math/rand" |
| 10 | "strings" |
| 11 | "testing" |
| 12 | ) |
| 13 | |
| 14 | type Btest struct { |
| 15 | a, b string |
| 16 | lcs []string |
| 17 | } |
| 18 | |
| 19 | var Btests = []Btest{ |
| 20 | {"aaabab", "abaab", []string{"abab", "aaab"}}, |
| 21 | {"aabbba", "baaba", []string{"aaba"}}, |
| 22 | {"cabbx", "cbabx", []string{"cabx", "cbbx"}}, |
| 23 | {"c", "cb", []string{"c"}}, |
| 24 | {"aaba", "bbb", []string{"b"}}, |
| 25 | {"bbaabb", "b", []string{"b"}}, |
| 26 | {"baaabb", "bbaba", []string{"bbb", "baa", "bab"}}, |
| 27 | {"baaabb", "abbab", []string{"abb", "bab", "aab"}}, |
| 28 | {"baaba", "aaabba", []string{"aaba"}}, |
| 29 | {"ca", "cba", []string{"ca"}}, |
| 30 | {"ccbcbc", "abba", []string{"bb"}}, |
| 31 | {"ccbcbc", "aabba", []string{"bb"}}, |
| 32 | {"ccb", "cba", []string{"cb"}}, |
| 33 | {"caef", "axe", []string{"ae"}}, |
| 34 | {"bbaabb", "baabb", []string{"baabb"}}, |
| 35 | // Example from Myers: |
| 36 | {"abcabba", "cbabac", []string{"caba", "baba", "cbba"}}, |
| 37 | {"3456aaa", "aaa", []string{"aaa"}}, |
| 38 | {"aaa", "aaa123", []string{"aaa"}}, |
| 39 | {"aabaa", "aacaa", []string{"aaaa"}}, |
| 40 | {"1a", "a", []string{"a"}}, |
| 41 | {"abab", "bb", []string{"bb"}}, |
| 42 | {"123", "ab", []string{""}}, |
| 43 | {"a", "b", []string{""}}, |
| 44 | {"abc", "123", []string{""}}, |
| 45 | {"aa", "aa", []string{"aa"}}, |
| 46 | {"abcde", "12345", []string{""}}, |
| 47 | {"aaa3456", "aaa", []string{"aaa"}}, |
| 48 | {"abcde", "12345a", []string{"a"}}, |
| 49 | {"ab", "123", []string{""}}, |
| 50 | {"1a2", "a", []string{"a"}}, |
| 51 | // for two-sided |
| 52 | {"babaab", "cccaba", []string{"aba"}}, |
| 53 | {"aabbab", "cbcabc", []string{"bab"}}, |
| 54 | {"abaabb", "bcacab", []string{"baab"}}, |
| 55 | {"abaabb", "abaaaa", []string{"abaa"}}, |
| 56 | {"bababb", "baaabb", []string{"baabb"}}, |
| 57 | {"abbbaa", "cabacc", []string{"aba"}}, |
| 58 | {"aabbaa", "aacaba", []string{"aaaa", "aaba"}}, |
| 59 | } |
| 60 | |
| 61 | func init() { |
| 62 | log.SetFlags(log.Lshortfile) |
| 63 | } |
| 64 | |
| 65 | func check(t *testing.T, str string, lcs lcs, want []string) { |
| 66 | t.Helper() |
| 67 | if !lcs.valid() { |
| 68 | t.Errorf("bad lcs %v", lcs) |
| 69 | } |
| 70 | var got strings.Builder |
| 71 | for _, dd := range lcs { |
| 72 | got.WriteString(str[dd.X : dd.X+dd.Len]) |
| 73 | } |
| 74 | ans := got.String() |
| 75 | for _, w := range want { |
| 76 | if ans == w { |
| 77 | return |
| 78 | } |
| 79 | } |
| 80 | t.Fatalf("str=%q lcs=%v want=%q got=%q", str, lcs, want, ans) |
| 81 | } |
| 82 | |
| 83 | func checkDiffs(t *testing.T, before string, diffs []Diff, after string) { |
| 84 | t.Helper() |
| 85 | var ans strings.Builder |
| 86 | sofar := 0 // index of position in before |
| 87 | for _, d := range diffs { |
| 88 | if sofar < d.Start { |
| 89 | ans.WriteString(before[sofar:d.Start]) |
| 90 | } |
| 91 | ans.WriteString(after[d.ReplStart:d.ReplEnd]) |
| 92 | sofar = d.End |
| 93 | } |
| 94 | ans.WriteString(before[sofar:]) |
| 95 | if ans.String() != after { |
| 96 | t.Fatalf("diff %v took %q to %q, not to %q", diffs, before, ans.String(), after) |
| 97 | } |
| 98 | } |
| 99 | |
| 100 | func lcslen(l lcs) int { |
| 101 | ans := 0 |
| 102 | for _, d := range l { |
| 103 | ans += int(d.Len) |
| 104 | } |
| 105 | return ans |
| 106 | } |
| 107 | |
| 108 | // return a random string of length n made of characters from s |
| 109 | func randstr(s string, n int) string { |
| 110 | src := []rune(s) |
| 111 | x := make([]rune, n) |
| 112 | for i := 0; i < n; i++ { |
| 113 | x[i] = src[rand.Intn(len(src))] |
| 114 | } |
| 115 | return string(x) |
| 116 | } |
| 117 | |
| 118 | func TestLcsFix(t *testing.T) { |
| 119 | tests := []struct{ before, after lcs }{ |
| 120 | {lcs{diag{0, 0, 3}, diag{2, 2, 5}, diag{3, 4, 5}, diag{8, 9, 4}}, lcs{diag{0, 0, 2}, diag{2, 2, 1}, diag{3, 4, 5}, diag{8, 9, 4}}}, |
| 121 | {lcs{diag{1, 1, 6}, diag{6, 12, 3}}, lcs{diag{1, 1, 5}, diag{6, 12, 3}}}, |
| 122 | {lcs{diag{0, 0, 4}, diag{3, 5, 4}}, lcs{diag{0, 0, 3}, diag{3, 5, 4}}}, |
| 123 | {lcs{diag{0, 20, 1}, diag{0, 0, 3}, diag{1, 20, 4}}, lcs{diag{0, 0, 3}, diag{3, 22, 2}}}, |
| 124 | {lcs{diag{0, 0, 4}, diag{1, 1, 2}}, lcs{diag{0, 0, 4}}}, |
| 125 | {lcs{diag{0, 0, 4}}, lcs{diag{0, 0, 4}}}, |
| 126 | {lcs{}, lcs{}}, |
| 127 | {lcs{diag{0, 0, 4}, diag{1, 1, 6}, diag{3, 3, 2}}, lcs{diag{0, 0, 1}, diag{1, 1, 6}}}, |
| 128 | } |
| 129 | for n, x := range tests { |
| 130 | got := x.before.fix() |
| 131 | if len(got) != len(x.after) { |
| 132 | t.Errorf("got %v, expected %v, for %v", got, x.after, x.before) |
| 133 | } |
| 134 | olen := lcslen(x.after) |
| 135 | glen := lcslen(got) |
| 136 | if olen != glen { |
| 137 | t.Errorf("%d: lens(%d,%d) differ, %v, %v, %v", n, glen, olen, got, x.after, x.before) |
| 138 | } |
| 139 | } |
| 140 | } |
| 141 |
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