Fix error when creating EventError(...) with message=None (#441)

linode_api4/polling.py

@@ -13,7 +13,7 @@ class EventError(Exception):
 
     def __init__(self, event_id: int, message: Optional[str]):
         # Edge case, sometimes the message is populated with an empty string
-        if len(message) < 1:
+        if message is not None and len(message) < 1:
             message = None
 
         self.event_id = event_id

test/unit/objects/polling_test.py

@@ -328,3 +328,17 @@ def test_wait_for_event_finished_failed(
             assert err.message == "oh no!"
         else:
             raise Exception("Expected event error, got none")
+
+    def test_event_error(
+        self,
+    ):
+        """
+        Tests that EventError objects can be constructed and
+        will be formatted to the correct output.
+
+        Tests for regression of TPT-3060
+        """
+
+        assert str(EventError(123, None)) == "Event 123 failed"
+        assert str(EventError(123, "")) == "Event 123 failed"
+        assert str(EventError(123, "foobar")) == "Event 123 failed: foobar"