diff --git a/tests/test_schemas_utils.py b/tests/test_schemas_utils.py
index 0732b3a..120ca88 100644
--- a/tests/test_schemas_utils.py
+++ b/tests/test_schemas_utils.py
@@ -9,9 +9,13 @@ def test_string_to_duration_days():
     assert string_to_duration("3w", target="days") == 21
     assert string_to_duration("3m", target="days") == 90
     assert string_to_duration("1y", target="days") == 365
+
     with pytest.raises(ValueError):
         string_to_duration("3h", target="days")
 
+    with pytest.raises(ValueError):
+        string_to_duration("1", target="days")
+
 
 def test_string_to_duration_hours():
     assert string_to_duration("1h", target="hours") == 1
@@ -19,3 +23,6 @@ def test_string_to_duration_hours():
     assert string_to_duration("1w", target="hours") == 7 * 24
     assert string_to_duration("3w", target="hours") == 21 * 24
     assert string_to_duration("3m", target="hours") == 3 * 30 * 24
+
+    with pytest.raises(ValueError):
+        string_to_duration("1", target="hours")