add test for util.get_str_class_num()

tests/unittests/test_util.py

@@ -3369,3 +3369,61 @@ def test_logexc_with_log_level(self, caplog, log_level):
             ),
             ("tests.unittests.test_util", logging.DEBUG, "an error occurred"),
         ]
+
+
+class TestRandStr:
+    def _get_str_class_num(str):
+        import string
+        str_class_num = 0
+        if any(c.islower() for c in str):
+            str_class_num += 1
+        if any(c.isupper() for c in str):
+            str_class_num += 1
+        if any(c.isdigit() for c in str):
+            str_class_num += 1
+        if any(c in string.punctuation for c in str):
+            str_class_num += 1
+        return str_class_num
+
+    @pytest.mark.parametrize(
+        "strlen, param_minclass, expected_minclass, expected_maxclass",
+        [
+            (1, 1, 1, 1),
+            (1, 2, 1, 1),
+            (1, 3, 1, 1),
+            (1, 4, 1, 1),
+            (2, 1, 1, 2),
+            (2, 2, 2, 2),
+            (2, 3, 2, 2),
+            (2, 4, 2, 2),
+            (3, 1, 1, 3),
+            (3, 2, 2, 3),
+            (3, 3, 3, 3),
+            (3, 4, 3, 3),
+            (4, 1, 1, 3),
+            (4, 2, 2, 3),
+            (4, 3, 3, 3),
+            (4, 4, 4, 4),
+            (5, 1, 1, 3),
+            (5, 2, 2, 3),
+            (5, 3, 3, 3),
+            (5, 4, 4, 4),
+            (5, 5, 4, 4),
+            (6, 1, 1, 3),
+            (6, 2, 2, 3),
+            (6, 3, 3, 3),
+            (6, 4, 4, 4),
+            (6, 5, 4, 4),
+            (6, 6, 4, 4),
+            (20, 1, 1, 3),
+            (20, 2, 2, 3),
+            (20, 3, 3, 3),
+            (20, 4, 4, 4),
+            (20, 5, 4, 4),
+        ],
+    )
+    def test_get_str_class_num(self, strlen, param_minclass, expected_minclass, expected_maxclass):
+        res_rand_str = util.rand_str_minclass(strlen, param_minclass)
+        actual_class = self._get_str_class_num(res_rand_str)
+        assert actual_class >= expected_minclass
+        assert actual_class <= expected_maxclass