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- // Copyright 2017, The Go Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style
- // license that can be found in the LICENSE.md file.
-
- package diff
-
- import (
- "fmt"
- "math/rand"
- "strings"
- "testing"
- "unicode"
- )
-
- func TestDifference(t *testing.T) {
- tests := []struct {
- // Before passing x and y to Difference, we strip all spaces so that
- // they can be used by the test author to indicate a missing symbol
- // in one of the lists.
- x, y string
- want string
- }{{
- x: "",
- y: "",
- want: "",
- }, {
- x: "#",
- y: "#",
- want: ".",
- }, {
- x: "##",
- y: "# ",
- want: ".X",
- }, {
- x: "a#",
- y: "A ",
- want: "MX",
- }, {
- x: "#a",
- y: " A",
- want: "XM",
- }, {
- x: "# ",
- y: "##",
- want: ".Y",
- }, {
- x: " #",
- y: "@#",
- want: "Y.",
- }, {
- x: "@#",
- y: " #",
- want: "X.",
- }, {
- x: "##########0123456789",
- y: " 0123456789",
- want: "XXXXXXXXXX..........",
- }, {
- x: " 0123456789",
- y: "##########0123456789",
- want: "YYYYYYYYYY..........",
- }, {
- x: "#####0123456789#####",
- y: " 0123456789 ",
- want: "XXXXX..........XXXXX",
- }, {
- x: " 0123456789 ",
- y: "#####0123456789#####",
- want: "YYYYY..........YYYYY",
- }, {
- x: "01234##########56789",
- y: "01234 56789",
- want: ".....XXXXXXXXXX.....",
- }, {
- x: "01234 56789",
- y: "01234##########56789",
- want: ".....YYYYYYYYYY.....",
- }, {
- x: "0123456789##########",
- y: "0123456789 ",
- want: "..........XXXXXXXXXX",
- }, {
- x: "0123456789 ",
- y: "0123456789##########",
- want: "..........YYYYYYYYYY",
- }, {
- x: "abcdefghij0123456789",
- y: "ABCDEFGHIJ0123456789",
- want: "MMMMMMMMMM..........",
- }, {
- x: "ABCDEFGHIJ0123456789",
- y: "abcdefghij0123456789",
- want: "MMMMMMMMMM..........",
- }, {
- x: "01234abcdefghij56789",
- y: "01234ABCDEFGHIJ56789",
- want: ".....MMMMMMMMMM.....",
- }, {
- x: "01234ABCDEFGHIJ56789",
- y: "01234abcdefghij56789",
- want: ".....MMMMMMMMMM.....",
- }, {
- x: "0123456789abcdefghij",
- y: "0123456789ABCDEFGHIJ",
- want: "..........MMMMMMMMMM",
- }, {
- x: "0123456789ABCDEFGHIJ",
- y: "0123456789abcdefghij",
- want: "..........MMMMMMMMMM",
- }, {
- x: "ABCDEFGHIJ0123456789 ",
- y: " 0123456789abcdefghij",
- want: "XXXXXXXXXX..........YYYYYYYYYY",
- }, {
- x: " 0123456789abcdefghij",
- y: "ABCDEFGHIJ0123456789 ",
- want: "YYYYYYYYYY..........XXXXXXXXXX",
- }, {
- x: "ABCDE0123456789 FGHIJ",
- y: " 0123456789abcdefghij",
- want: "XXXXX..........YYYYYMMMMM",
- }, {
- x: " 0123456789abcdefghij",
- y: "ABCDE0123456789 FGHIJ",
- want: "YYYYY..........XXXXXMMMMM",
- }, {
- x: "ABCDE01234F G H I J 56789 ",
- y: " 01234 a b c d e56789fghij",
- want: "XXXXX.....XYXYXYXYXY.....YYYYY",
- }, {
- x: " 01234a b c d e 56789fghij",
- y: "ABCDE01234 F G H I J56789 ",
- want: "YYYYY.....XYXYXYXYXY.....XXXXX",
- }, {
- x: "FGHIJ01234ABCDE56789 ",
- y: " 01234abcde56789fghij",
- want: "XXXXX.....MMMMM.....YYYYY",
- }, {
- x: " 01234abcde56789fghij",
- y: "FGHIJ01234ABCDE56789 ",
- want: "YYYYY.....MMMMM.....XXXXX",
- }, {
- x: "ABCAB BA ",
- y: " C BABAC",
- want: "XX.X.Y..Y",
- }, {
- x: "# #### ###",
- y: "#y####yy###",
- want: ".Y....YY...",
- }, {
- x: "# #### # ##x#x",
- y: "#y####y y## # ",
- want: ".Y....YXY..X.X",
- }, {
- x: "###z#z###### x #",
- y: "#y##Z#Z###### yy#",
- want: ".Y..M.M......XYY.",
- }, {
- x: "0 12z3x 456789 x x 0",
- y: "0y12Z3 y456789y y y0",
- want: ".Y..M.XY......YXYXY.",
- }, {
- x: "0 2 4 6 8 ..................abXXcdEXF.ghXi",
- y: " 1 3 5 7 9..................AB CDE F.GH I",
- want: "XYXYXYXYXY..................MMXXMM.X..MMXM",
- }, {
- x: "I HG.F EDC BA..................9 7 5 3 1 ",
- y: "iXhg.FXEdcXXba.................. 8 6 4 2 0",
- want: "MYMM..Y.MMYYMM..................XYXYXYXYXY",
- }, {
- x: "x1234",
- y: " 1234",
- want: "X....",
- }, {
- x: "x123x4",
- y: " 123 4",
- want: "X...X.",
- }, {
- x: "x1234x56",
- y: " 1234 ",
- want: "X....XXX",
- }, {
- x: "x1234xxx56",
- y: " 1234 56",
- want: "X....XXX..",
- }, {
- x: ".1234...ab",
- y: " 1234 AB",
- want: "X....XXXMM",
- }, {
- x: "x1234xxab.",
- y: " 1234 AB ",
- want: "X....XXMMX",
- }, {
- x: " 0123456789",
- y: "9012345678 ",
- want: "Y.........X",
- }, {
- x: " 0123456789",
- y: "8901234567 ",
- want: "YY........XX",
- }, {
- x: " 0123456789",
- y: "7890123456 ",
- want: "YYY.......XXX",
- }, {
- x: " 0123456789",
- y: "6789012345 ",
- want: "YYYY......XXXX",
- }, {
- x: "0123456789 ",
- y: " 5678901234",
- want: "XXXXX.....YYYYY",
- }, {
- x: "0123456789 ",
- y: " 4567890123",
- want: "XXXX......YYYY",
- }, {
- x: "0123456789 ",
- y: " 3456789012",
- want: "XXX.......YYY",
- }, {
- x: "0123456789 ",
- y: " 2345678901",
- want: "XX........YY",
- }, {
- x: "0123456789 ",
- y: " 1234567890",
- want: "X.........Y",
- }, {
- x: "0 1 2 3 45 6 7 8 9 ",
- y: " 9 8 7 6 54 3 2 1 0",
- want: "XYXYXYXYX.YXYXYXYXY",
- }, {
- x: "0 1 2345678 9 ",
- y: " 6 72 5 819034",
- want: "XYXY.XX.XX.Y.YYY",
- }, {
- x: "F B Q M O I G T L N72X90 E 4S P 651HKRJU DA 83CVZW",
- y: " 5 W H XO10R9IV K ZLCTAJ8P3N SEQM4 7 2G6 UBD F ",
- want: "XYXYXYXY.YYYY.YXYXY.YYYYYYY.XXXXXY.YY.XYXYY.XXXXXX.Y.XYXXXXXX",
- }}
-
- for _, tt := range tests {
- t.Run("", func(t *testing.T) {
- x := strings.Replace(tt.x, " ", "", -1)
- y := strings.Replace(tt.y, " ", "", -1)
- es := testStrings(t, x, y)
- if got := es.String(); got != tt.want {
- t.Errorf("Difference(%s, %s):\ngot %s\nwant %s", x, y, got, tt.want)
- }
- })
- }
- }
-
- func TestDifferenceFuzz(t *testing.T) {
- tests := []struct{ px, py, pm float32 }{
- {px: 0.0, py: 0.0, pm: 0.1},
- {px: 0.0, py: 0.1, pm: 0.0},
- {px: 0.1, py: 0.0, pm: 0.0},
- {px: 0.0, py: 0.1, pm: 0.1},
- {px: 0.1, py: 0.0, pm: 0.1},
- {px: 0.2, py: 0.2, pm: 0.2},
- {px: 0.3, py: 0.1, pm: 0.2},
- {px: 0.1, py: 0.3, pm: 0.2},
- {px: 0.2, py: 0.2, pm: 0.2},
- {px: 0.3, py: 0.3, pm: 0.3},
- {px: 0.1, py: 0.1, pm: 0.5},
- {px: 0.4, py: 0.1, pm: 0.5},
- {px: 0.3, py: 0.2, pm: 0.5},
- {px: 0.2, py: 0.3, pm: 0.5},
- {px: 0.1, py: 0.4, pm: 0.5},
- }
-
- for i, tt := range tests {
- t.Run(fmt.Sprintf("P%d", i), func(t *testing.T) {
- // Sweep from 1B to 1KiB.
- for n := 1; n <= 1024; n <<= 1 {
- t.Run(fmt.Sprintf("N%d", n), func(t *testing.T) {
- for j := 0; j < 10; j++ {
- x, y := generateStrings(n, tt.px, tt.py, tt.pm, int64(j))
- testStrings(t, x, y)
- }
- })
- }
- })
- }
- }
-
- func BenchmarkDifference(b *testing.B) {
- for n := 1 << 10; n <= 1<<20; n <<= 2 {
- b.Run(fmt.Sprintf("N%d", n), func(b *testing.B) {
- x, y := generateStrings(n, 0.05, 0.05, 0.10, 0)
- b.ReportAllocs()
- b.SetBytes(int64(len(x) + len(y)))
- for i := 0; i < b.N; i++ {
- Difference(len(x), len(y), func(ix, iy int) Result {
- return compareByte(x[ix], y[iy])
- })
- }
- })
- }
- }
-
- func generateStrings(n int, px, py, pm float32, seed int64) (string, string) {
- if px+py+pm > 1.0 {
- panic("invalid probabilities")
- }
- py += px
- pm += py
-
- b := make([]byte, n)
- r := rand.New(rand.NewSource(seed))
- r.Read(b)
-
- var x, y []byte
- for len(b) > 0 {
- switch p := r.Float32(); {
- case p < px: // UniqueX
- x = append(x, b[0])
- case p < py: // UniqueY
- y = append(y, b[0])
- case p < pm: // Modified
- x = append(x, 'A'+(b[0]%26))
- y = append(y, 'a'+(b[0]%26))
- default: // Identity
- x = append(x, b[0])
- y = append(y, b[0])
- }
- b = b[1:]
- }
- return string(x), string(y)
- }
-
- func testStrings(t *testing.T, x, y string) EditScript {
- es := Difference(len(x), len(y), func(ix, iy int) Result {
- return compareByte(x[ix], y[iy])
- })
- if es.LenX() != len(x) {
- t.Errorf("es.LenX = %d, want %d", es.LenX(), len(x))
- }
- if es.LenY() != len(y) {
- t.Errorf("es.LenY = %d, want %d", es.LenY(), len(y))
- }
- if !validateScript(x, y, es) {
- t.Errorf("invalid edit script: %v", es)
- }
- return es
- }
-
- func validateScript(x, y string, es EditScript) bool {
- var bx, by []byte
- for _, e := range es {
- switch e {
- case Identity:
- if !compareByte(x[len(bx)], y[len(by)]).Equal() {
- return false
- }
- bx = append(bx, x[len(bx)])
- by = append(by, y[len(by)])
- case UniqueX:
- bx = append(bx, x[len(bx)])
- case UniqueY:
- by = append(by, y[len(by)])
- case Modified:
- if !compareByte(x[len(bx)], y[len(by)]).Similar() {
- return false
- }
- bx = append(bx, x[len(bx)])
- by = append(by, y[len(by)])
- }
- }
- return string(bx) == x && string(by) == y
- }
-
- // compareByte returns a Result where the result is Equal if x == y,
- // similar if x and y differ only in casing, and different otherwise.
- func compareByte(x, y byte) (r Result) {
- switch {
- case x == y:
- return equalResult // Identity
- case unicode.ToUpper(rune(x)) == unicode.ToUpper(rune(y)):
- return similarResult // Modified
- default:
- return differentResult // UniqueX or UniqueY
- }
- }
-
- var (
- equalResult = Result{NumDiff: 0}
- similarResult = Result{NumDiff: 1}
- differentResult = Result{NumDiff: 2}
- )
-
- func TestResult(t *testing.T) {
- tests := []struct {
- result Result
- wantEqual bool
- wantSimilar bool
- }{
- // equalResult is equal since NumDiff == 0, by definition of Equal method.
- {equalResult, true, true},
- // similarResult is similar since it is a binary result where only one
- // element was compared (i.e., Either NumSame==1 or NumDiff==1).
- {similarResult, false, true},
- // differentResult is different since there are enough differences that
- // it isn't even considered similar.
- {differentResult, false, false},
-
- // Zero value is always equal.
- {Result{NumSame: 0, NumDiff: 0}, true, true},
-
- // Binary comparisons (where NumSame+NumDiff == 1) are always similar.
- {Result{NumSame: 1, NumDiff: 0}, true, true},
- {Result{NumSame: 0, NumDiff: 1}, false, true},
-
- // More complex ratios. The exact ratio for similarity may change,
- // and may require updates to these test cases.
- {Result{NumSame: 1, NumDiff: 1}, false, true},
- {Result{NumSame: 1, NumDiff: 2}, false, true},
- {Result{NumSame: 1, NumDiff: 3}, false, false},
- {Result{NumSame: 2, NumDiff: 1}, false, true},
- {Result{NumSame: 2, NumDiff: 2}, false, true},
- {Result{NumSame: 2, NumDiff: 3}, false, true},
- {Result{NumSame: 3, NumDiff: 1}, false, true},
- {Result{NumSame: 3, NumDiff: 2}, false, true},
- {Result{NumSame: 3, NumDiff: 3}, false, true},
- {Result{NumSame: 1000, NumDiff: 0}, true, true},
- {Result{NumSame: 1000, NumDiff: 1}, false, true},
- {Result{NumSame: 1000, NumDiff: 2}, false, true},
- {Result{NumSame: 0, NumDiff: 1000}, false, false},
- {Result{NumSame: 1, NumDiff: 1000}, false, false},
- {Result{NumSame: 2, NumDiff: 1000}, false, false},
- }
-
- for _, tt := range tests {
- if got := tt.result.Equal(); got != tt.wantEqual {
- t.Errorf("%#v.Equal() = %v, want %v", tt.result, got, tt.wantEqual)
- }
- if got := tt.result.Similar(); got != tt.wantSimilar {
- t.Errorf("%#v.Similar() = %v, want %v", tt.result, got, tt.wantSimilar)
- }
- }
- }
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