Added more tests

re_test.go

@@ -25,6 +25,10 @@ var reTests = []struct {
 	{"b*a*a", "bba", []matchIndex{{0, 3}}},
 	{"(ab)+", "abcabddd", []matchIndex{{0, 2}, {3, 5}}},
 	{"a(b(c|d)*)*", "abccbd", []matchIndex{{0, 6}}},
+	{"a(b|c)*d+", "abccdd", []matchIndex{{0, 6}}},
+	{"a*", "", []matchIndex{{0, 0}}},
+	{"a|b", "c", []matchIndex{}},
+	{"(a|b)*c", "aabbc", []matchIndex{{0, 5}}},
 }
 
 func TestFindAllMatches(t *testing.T) {