Add more tests for diff highlighting (#12467)

Adding some more tests for different cases to make sure they keep working

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

Author: mrsdizzie

services/gitdiff/gitdiff.go

@@ -181,7 +181,7 @@ var (
 	removedCodePrefix = []byte(`<span class="removed-code">`)
 	codeTagSuffix     = []byte(`</span>`)
 )
-var addSpanRegex = regexp.MustCompile(`<span class="[a-z]*$`)
+var addSpanRegex = regexp.MustCompile(`<span [class="[a-z]*]*$`)
 
 func diffToHTML(fileName string, diffs []diffmatchpatch.Diff, lineType DiffLineType) template.HTML {
 	buf := bytes.NewBuffer(nil)

services/gitdiff/gitdiff_test.go

@@ -60,6 +60,21 @@ func TestDiffToHTML(t *testing.T) {
 		{Type: dmp.DiffInsert, Text: "ge</span><span class=\"p\">.</span><span class=\"nx\">Milestone</span><span class=\"p\">,</span> <span class=\"nx\">from</span><span class=\"p\">,</span> <span class=\"nx\">milestoneID"},
 		{Type: dmp.DiffEqual, Text: "</span><span class=\"p\">)</span>"},
 	}, DiffLineDel))
+
+	assertEqual(t, "<span class=\"nx\">r</span><span class=\"p\">.</span><span class=\"nf\">WrapperRenderer</span><span class=\"p\">(</span><span class=\"nx\">w</span><span class=\"p\">,</span> <span class=\"nx\"><span class=\"removed-code\">language</span></span><span class=\"removed-code\"><span class=\"p\">,</span> <span class=\"kc\">true</span><span class=\"p\">,</span> <span class=\"nx\">attrs</span></span><span class=\"p\">,</span> <span class=\"kc\">false</span><span class=\"p\">)</span>", diffToHTML("", []dmp.Diff{
+		{Type: dmp.DiffEqual, Text: "<span class=\"nx\">r</span><span class=\"p\">.</span><span class=\"nf\">WrapperRenderer</span><span class=\"p\">(</span><span class=\"nx\">w</span><span class=\"p\">,</span> <span class=\"nx\">"},
+		{Type: dmp.DiffDelete, Text: "language</span><span "},
+		{Type: dmp.DiffEqual, Text: "c"},
+		{Type: dmp.DiffDelete, Text: "lass=\"p\">,</span> <span class=\"kc\">true</span><span class=\"p\">,</span> <span class=\"nx\">attrs"},
+		{Type: dmp.DiffEqual, Text: "</span><span class=\"p\">,</span> <span class=\"kc\">false</span><span class=\"p\">)</span>"},
+	}, DiffLineDel))
+
+	assertEqual(t, "<span class=\"added-code\">language</span></span><span class=\"added-code\"><span class=\"p\">,</span> <span class=\"kc\">true</span><span class=\"p\">,</span> <span class=\"nx\">attrs</span></span><span class=\"p\">,</span> <span class=\"kc\">false</span><span class=\"p\">)</span>", diffToHTML("", []dmp.Diff{
+		{Type: dmp.DiffInsert, Text: "language</span><span "},
+		{Type: dmp.DiffEqual, Text: "c"},
+		{Type: dmp.DiffInsert, Text: "lass=\"p\">,</span> <span class=\"kc\">true</span><span class=\"p\">,</span> <span class=\"nx\">attrs"},
+		{Type: dmp.DiffEqual, Text: "</span><span class=\"p\">,</span> <span class=\"kc\">false</span><span class=\"p\">)</span>"},
+	}, DiffLineAdd))
 }
 
 func TestParsePatch(t *testing.T) {