95 lines
2.3 KiB
Go
95 lines
2.3 KiB
Go
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// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
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// SPDX-License-Identifier: BSD-3-Clause
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package main
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import (
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"slices"
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"strings"
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"testing"
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)
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func lines(ss ...string) []string { return ss }
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func TestUnifiedDiffIdentical(t *testing.T) {
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if got := unifiedDiff("f", lines("a", "b"), lines("a", "b")); got != "" {
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t.Errorf("identical inputs produced %q, want empty", got)
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}
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}
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func TestUnifiedDiffSingleChange(t *testing.T) {
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a := lines("1", "2", "3", "4", "5", "6", "7", "8")
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b := lines("1", "2", "3!", "4", "5", "6", "7", "8")
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want := "--- f\n+++ f\n" +
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"@@ -1,6 +1,6 @@\n" +
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" 1\n 2\n-3\n+3!\n 4\n 5\n 6\n"
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if got := unifiedDiff("f", a, b); got != want {
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t.Errorf("diff = %q, want %q", got, want)
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}
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}
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func TestUnifiedDiffInsertAtStart(t *testing.T) {
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got := unifiedDiff("f", lines("x"), lines("new", "x"))
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// The single existing line is shown as trailing context, so the hunk
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// covers it.
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want := "--- f\n+++ f\n@@ -1,1 +1,2 @@\n+new\n x\n"
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if got != want {
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t.Errorf("diff = %q, want %q", got, want)
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}
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}
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func TestUnifiedDiffDeleteAtEnd(t *testing.T) {
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got := unifiedDiff("f", lines("x", "y"), lines("x"))
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want := "--- f\n+++ f\n@@ -1,2 +1,1 @@\n x\n-y\n"
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if got != want {
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t.Errorf("diff = %q, want %q", got, want)
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}
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}
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func TestUnifiedDiffTwoHunks(t *testing.T) {
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var a, b []string
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for i := 1; i <= 20; i++ {
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a = append(a, itoa(i))
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b = append(b, itoa(i))
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}
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b[1] = "2!"
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b[17] = "18!"
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got := unifiedDiff("f", a, b)
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if !strings.Contains(got, "@@ -1,5 +1,5 @@\n 1\n-2\n+2!\n 3\n 4\n 5\n") {
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t.Errorf("first hunk wrong:\n%s", got)
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}
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if !strings.Contains(got, "@@ -15,6 +15,6 @@\n 15\n 16\n 17\n-18\n+18!\n 19\n 20\n") {
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t.Errorf("second hunk wrong:\n%s", got)
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}
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}
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// TestUnifiedDiffAdjacentHunks merges changes separated by exactly twice the
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// context into one hunk.
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func TestUnifiedDiffAdjacentHunks(t *testing.T) {
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a := lines("1", "2", "3", "4", "5", "6", "7", "8")
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b := slices.Clone(a)
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b[0] = "1!"
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b[7] = "8!"
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got := unifiedDiff("f", a, b)
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want := "--- f\n+++ f\n" +
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"@@ -1,8 +1,8 @@\n" +
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"-1\n+1!\n 2\n 3\n 4\n 5\n 6\n 7\n-8\n+8!\n"
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if got != want {
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t.Errorf("diff = %q, want %q", got, want)
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}
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}
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func itoa(n int) string {
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if n == 0 {
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return "0"
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}
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var buf [4]byte
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i := len(buf)
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for n > 0 {
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i--
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buf[i] = byte('0' + n%10)
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n /= 10
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}
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return string(buf[i:])
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}
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