Add additional parse tests

tests/test_api.py

@@ -43,6 +43,24 @@
 class TestStruct(unittest.TestCase):
     """Test the data structures."""
 
+    def test_default_prefix(self) -> None:
+        """Test a default (empty) prefix."""
+        ref = Reference.from_curie(":something")
+        self.assertEqual("", ref.prefix)
+        self.assertEqual("something", ref.identifier)
+
+    def test_default_identifier(self) -> None:
+        """Test a default (empty) identifier."""
+        ref = Reference.from_curie("p1:")
+        self.assertEqual("p1", ref.prefix)
+        self.assertEqual("", ref.identifier)
+
+    def test_multiple_delimiters(self) -> None:
+        """Test a default (empty) identifier."""
+        ref = Reference.from_curie("a1:b2:c3")
+        self.assertEqual("a1", ref.prefix)
+        self.assertEqual("b2:c3", ref.identifier)
+
     def test_records(self):
         """Test a list of records."""
         records = Records.parse_obj([{"prefix": "chebi", "uri_prefix": CHEBI_URI_PREFIX}])