fix and extend tests

tests/test_ulid.py

@@ -1,20 +1,34 @@
 """Plugin tests."""
+import pytest
 
-from cmem_plugin_ulid.transform import ULIDTransformPlugin
+from cmem_plugin_ulid.transform import ULIDTransformPlugin, URN_PREFIX
 
 
-def test_transform_execution_with_optional_input():
-    """Test Lifetime with optional input"""
-    result = ULIDTransformPlugin().transform(inputs=[])
+def test_execution():
+    """Test execution"""
+    # default case
+    assert len(ULIDTransformPlugin().transform(inputs=[])) == 1
+
+    # multiple values
+    assert len(ULIDTransformPlugin(number_of_values=2).transform(inputs=[])) == 2
+    assert len(ULIDTransformPlugin(number_of_values=3).transform(inputs=[])) == 3
+
+    # as urn
+    result = ULIDTransformPlugin(generate_urn=True).transform(inputs=[])
     assert len(result) == 1
+    for _ in result:
+        assert _.startswith(URN_PREFIX)
 
-    result = ULIDTransformPlugin(number_of_values=2).transform(inputs=[])
-    assert len(result) == 2
 
+def test_fails():
+    """Test fails."""
+    # no inputs allowed
+    with pytest.raises(ValueError):
+        ULIDTransformPlugin().transform(
+            inputs=[["2000-05-22", "2021-12-12", "1904-02-29"]]
+        )
 
-def test_transform_execution_with_inputs():
-    """Test Lifetime with sequence of inputs."""
-    result = ULIDTransformPlugin().transform(
-        inputs=[["2000-05-22", "2021-12-12", "1904-02-29"]]
-    )
-    assert len(result) == 1
+    with pytest.raises(ValueError):
+        ULIDTransformPlugin(number_of_values=-0).transform(inputs=[])
+    with pytest.raises(ValueError):
+        ULIDTransformPlugin(number_of_values=-1).transform(inputs=[])