1 files changed, 126 insertions, 0 deletions
diff --git a/services/gitdiff/highlightdiff_test.go b/services/gitdiff/highlightdiff_test.go
new file mode 100644
index 0000000000..1cd78bc942
--- /dev/null
+++ b/services/gitdiff/highlightdiff_test.go
@@ -0,0 +1,126 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package gitdiff
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/sergi/go-diff/diffmatchpatch"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDiffWithHighlight(t *testing.T) {
+	hcd := newHighlightCodeDiff()
+	diffs := hcd.diffWithHighlight(
+		"main.v", "",
+		"		run('<>')\n",
+		"		run(db)\n",
+	)
+
+	expected := `		<span class="n">run</span><span class="o">(</span><span class="removed-code"><span class="k">&#39;</span><span class="o">&lt;</span><span class="o">&gt;</span><span class="k">&#39;</span></span><span class="o">)</span>` + "\n"
+	output := diffToHTML(nil, diffs, DiffLineDel)
+	assert.Equal(t, expected, output)
+
+	expected = `		<span class="n">run</span><span class="o">(</span><span class="added-code"><span class="n">db</span></span><span class="o">)</span>` + "\n"
+	output = diffToHTML(nil, diffs, DiffLineAdd)
+	assert.Equal(t, expected, output)
+
+	hcd = newHighlightCodeDiff()
+	hcd.placeholderTokenMap['O'] = "<span>"
+	hcd.placeholderTokenMap['C'] = "</span>"
+	diff := diffmatchpatch.Diff{}
+
+	diff.Text = "OC"
+	hcd.recoverOneDiff(&diff)
+	assert.Equal(t, "<span></span>", diff.Text)
+
+	diff.Text = "O"
+	hcd.recoverOneDiff(&diff)
+	assert.Equal(t, "<span></span>", diff.Text)
+
+	diff.Text = "C"
+	hcd.recoverOneDiff(&diff)
+	assert.Equal(t, "", diff.Text)
+}
+
+func TestDiffWithHighlightPlaceholder(t *testing.T) {
+	hcd := newHighlightCodeDiff()
+	diffs := hcd.diffWithHighlight(
+		"main.js", "",
+		"a='\U00100000'",
+		"a='\U0010FFFD''",
+	)
+	assert.Equal(t, "", hcd.placeholderTokenMap[0x00100000])
+	assert.Equal(t, "", hcd.placeholderTokenMap[0x0010FFFD])
+
+	expected := fmt.Sprintf(`<span class="line"><span class="cl"><span class="nx">a</span><span class="o">=</span><span class="s1">&#39;</span><span class="removed-code">%s</span>&#39;</span></span>`, "\U00100000")
+	output := diffToHTML(hcd.lineWrapperTags, diffs, DiffLineDel)
+	assert.Equal(t, expected, output)
+
+	hcd = newHighlightCodeDiff()
+	diffs = hcd.diffWithHighlight(
+		"main.js", "",
+		"a='\U00100000'",
+		"a='\U0010FFFD'",
+	)
+	expected = fmt.Sprintf(`<span class="nx">a</span><span class="o">=</span><span class="s1">&#39;</span><span class="added-code">%s</span>&#39;`, "\U0010FFFD")
+	output = diffToHTML(nil, diffs, DiffLineAdd)
+	assert.Equal(t, expected, output)
+}
+
+func TestDiffWithHighlightPlaceholderExhausted(t *testing.T) {
+	hcd := newHighlightCodeDiff()
+	hcd.placeholderMaxCount = 0
+	diffs := hcd.diffWithHighlight(
+		"main.js", "",
+		"'",
+		``,
+	)
+	output := diffToHTML(nil, diffs, DiffLineDel)
+	expected := fmt.Sprintf(`<span class="removed-code">%s#39;</span>`, "\uFFFD")
+	assert.Equal(t, expected, output)
+
+	hcd = newHighlightCodeDiff()
+	hcd.placeholderMaxCount = 0
+	diffs = hcd.diffWithHighlight(
+		"main.js", "",
+		"a < b",
+		"a > b",
+	)
+	output = diffToHTML(nil, diffs, DiffLineDel)
+	expected = fmt.Sprintf(`a %s<span class="removed-code">l</span>t; b`, "\uFFFD")
+	assert.Equal(t, expected, output)
+
+	output = diffToHTML(nil, diffs, DiffLineAdd)
+	expected = fmt.Sprintf(`a %s<span class="added-code">g</span>t; b`, "\uFFFD")
+	assert.Equal(t, expected, output)
+}
+
+func TestDiffWithHighlightTagMatch(t *testing.T) {
+	totalOverflow := 0
+	for i := 0; i < 100; i++ {
+		hcd := newHighlightCodeDiff()
+		hcd.placeholderMaxCount = i
+		diffs := hcd.diffWithHighlight(
+			"main.js", "",
+			"a='1'",
+			"b='2'",
+		)
+		totalOverflow += hcd.placeholderOverflowCount
+
+		output := diffToHTML(nil, diffs, DiffLineDel)
+		c1 := strings.Count(output, "<span")
+		c2 := strings.Count(output, "</span")
+		assert.Equal(t, c1, c2)
+
+		output = diffToHTML(nil, diffs, DiffLineAdd)
+		c1 = strings.Count(output, "<span")
+		c2 = strings.Count(output, "</span")
+		assert.Equal(t, c1, c2)
+	}
+	assert.NotZero(t, totalOverflow)
+}