Fix unit test that was looking for the wrong behavior.

First problem was just that the test assumed it could register a
dataset type after the QG was made and not run into trouble when
running that QG.

Second problem was that it was just expecting something other than what
its own code comments suggested, which was also contrary to correct
behavior.

tests/test_simple_pipeline_executor.py

@@ -226,12 +226,6 @@ def test_from_pipeline_intermediates_differ(self):
 
     def test_from_pipeline_output_differ(self):
         """Run pipeline but output definition in registry differs."""
-        executor = self._configure_pipeline(
-            NoDimensionsTestTask.ConfigClass,
-            NoDimensionsTestTask.ConfigClass,
-            storageClass_a="TaskMetadataLike",
-        )
-
         # Pre-define the "output" storage class to be something that is
         # like a dict but is not a dict. This will fail unless storage
         # class conversion is supported in put and get.
@@ -243,14 +237,21 @@ def test_from_pipeline_output_differ(self):
             )
         )
 
+        executor = self._configure_pipeline(
+            NoDimensionsTestTask.ConfigClass,
+            NoDimensionsTestTask.ConfigClass,
+            storageClass_a="TaskMetadataLike",
+        )
+
         with self.assertLogs("lsst", level="INFO") as cm:
             quanta = executor.run(register_dataset_types=True, save_versions=False)
-        # a has been told to return a TaskMetadata but will convert to dict.
+        # a has been told to return a TaskMetadata but this will convert to
+        # dict on read by b.
         # b returns a dict and that is converted to TaskMetadata on put.
         self._test_logs(cm.output, "dict", "lsst.pipe.base.TaskMetadata", "dict", "dict")
 
         self.assertEqual(len(quanta), 2)
-        self.assertEqual(self.butler.get("intermediate"), {"zero": 0, "one": 1})
+        self.assertEqual(self.butler.get("intermediate").to_dict(), {"zero": 0, "one": 1})
         self.assertEqual(self.butler.get("output").to_dict(), {"zero": 0, "one": 1, "two": 2})
 
     def test_from_pipeline_input_differ(self):