Added test cases

re_test.go

@@ -19,6 +19,8 @@ var reTests = []struct {
 	{"(b|c|A)", "ooaoobocA", []matchIndex{{5, 6}, {7, 8}, {8, 9}}},
 	{"ab*", "a", []matchIndex{{0, 1}}},
 	{"ab*", "abb", []matchIndex{{0, 3}}},
+	{"a*b", "aaab", []matchIndex{{0, 4}}},
+	{"a*b", "qwqw", []matchIndex{}},
 	{"(abc)*", "abcabcabc", []matchIndex{{0, 9}}},
 	{"((abc)|(def))*", "abcdef", []matchIndex{{0, 6}}},
 	{"(abc)*|(def)*", "abcdef", []matchIndex{{0, 3}, {3, 3}, {3, 6}, {6, 6}}},
@@ -30,6 +32,9 @@ var reTests = []struct {
 	{"a|b", "c", []matchIndex{}},
 	{"(a|b)*c", "aabbc", []matchIndex{{0, 5}}},
 	{"a*", "aaaaaaaa", []matchIndex{{0, 8}, {8, 8}}},
+	{"ab?", "ab", []matchIndex{{0, 2}}},
+	{"a?b", "ab", []matchIndex{{0, 2}}},
+	{"a?", "", []matchIndex{{0, 0}}},
 }
 
 func TestFindAllMatches(t *testing.T) {