Fix git diff tests

models/git_diff_test.go

 }
 
 func TestDiffToHTML(t *testing.T) {
-	assertEqual(t, "foo <span class=\"added-code\">bar</span> biz", diffToHTML([]dmp.Diff{
+	assertEqual(t, "+foo <span class=\"added-code\">bar</span> biz", diffToHTML([]dmp.Diff{
 		dmp.Diff{dmp.DiffEqual, "foo "},
 		dmp.Diff{dmp.DiffInsert, "bar"},
 		dmp.Diff{dmp.DiffDelete, " baz"},
 		dmp.Diff{dmp.DiffEqual, " biz"},
 	}, DIFF_LINE_ADD))
 
-	assertEqual(t, "foo <span class=\"removed-code\">bar</span> biz", diffToHTML([]dmp.Diff{
+	assertEqual(t, "-foo <span class=\"removed-code\">bar</span> biz", diffToHTML([]dmp.Diff{
 		dmp.Diff{dmp.DiffEqual, "foo "},
 		dmp.Diff{dmp.DiffDelete, "bar"},
 		dmp.Diff{dmp.DiffInsert, " baz"},