diff --git a/contracts/tools/tests/test_parameters.py b/contracts/tools/tests/test_parameters.py
new file mode 100644
index 0000000..afe67b4
--- /dev/null
+++ b/contracts/tools/tests/test_parameters.py
@@ -0,0 +1,22 @@
+import pytest
+from datetime import date
+
+from pic_contracts.parameters import _parse_date
+
+
+def test_parse_date_with_none():
+    assert _parse_date(None) is None
+
+
+def test_parse_date_with_valid_iso_string():
+    assert _parse_date("2023-10-25") == date(2023, 10, 25)
+
+
+def test_parse_date_with_invalid_string_raises_value_error():
+    with pytest.raises(ValueError):
+        _parse_date("invalid-date")
+
+
+def test_parse_date_with_invalid_type_raises_type_error():
+    with pytest.raises(TypeError):
+        _parse_date(123)