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