Add test for require_description flag

Add a test which will verify that a missing description triggers an
error when the flag is set.

tests/test_cli.py

@@ -140,7 +140,9 @@ def test_validate_rsp(self) -> None:
         result = runner.invoke(
             cli, ["validate", "-s", "RSP", "--require-description", TEST_YAML], catch_exceptions=False
         )
-        # This state needs to be reset for subsequent tests.
+        # This state needs to be reset for subsequent tests. This is not an
+        # issue when running the actual command line tool as it will execute
+        # in its own system process.
         Schema.require_description(False)
         self.assertEqual(result.exit_code, 0)
 

tests/test_datamodel.py

@@ -121,6 +121,19 @@ def test_validation(self) -> None:
         with self.assertRaises(ValidationError):
             Column(**units_data)
 
+        # Creating a column without a description when required should throw an
+        # error.
+        Schema.require_description(True)
+        with self.assertRaises(ValidationError):
+            col = Column(
+                **{
+                    "name": "testColumn",
+                    "@id": "#test_col_id",
+                    "datatype": "string",
+                }
+            )
+        Schema.require_description(False)
+
 
 class ConstraintTestCase(unittest.TestCase):
     """Test the `UniqueConstraint`, `Index`, `CheckCosntraint`, and