github.com/cockroachdb/tools@v0.0.0-20230222021103-a6d27438930d/internal/diff/lcs/common_test.go (about)

     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  }