Add tests

tests/unit/test_parsers.py

@@ -0,0 +1,17 @@
+from typing import Literal
+
+import pytest
+
+from dataclass_wizard.parsers import LiteralParser
+
+
+class TestLiteralParser:
+    @pytest.fixture
+    def literal_parser(self) -> LiteralParser:
+        return LiteralParser(cls=object, base_type=Literal["foo"], extras={})
+
+    def test_literal_parser_dunder_contains_succeeds_if_item_in_keys_of_base_type(self, literal_parser):
+        assert "foo" in literal_parser
+
+    def test_literal_parser_dunder_contains_fails_if_item_not_in_keys_of_base_type(self, literal_parser):
+        assert "bar" not in literal_parser