diff --git a/invokeai/app/invocations/baseinvocation.py b/invokeai/app/invocations/baseinvocation.py
index 5edae5342d..a1303d38ef 100644
--- a/invokeai/app/invocations/baseinvocation.py
+++ b/invokeai/app/invocations/baseinvocation.py
@@ -183,7 +183,7 @@ class BaseInvocation(ABC, BaseModel):
         """Gets a pydantc TypeAdapter for the union of all invocation types."""
         if not cls._typeadapter:
             InvocationsUnion = TypeAliasType(
-                "InvocationsUnion", Annotated[Union[tuple(cls._invocation_classes)], Field(discriminator="type")]
+                "InvocationsUnion", Annotated[Union[tuple(cls.get_invocations())], Field(discriminator="type")]
             )
             cls._typeadapter = TypeAdapter(InvocationsUnion)
         return cls._typeadapter
diff --git a/tests/test_config.py b/tests/test_config.py
index 740a4866dd..c33a344eee 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -6,6 +6,10 @@ import pytest
 from omegaconf import OmegaConf
 from pydantic import ValidationError
 
+from invokeai.app.invocations.baseinvocation import BaseInvocation
+from invokeai.app.invocations.primitives import FloatInvocation, IntegerInvocation, StringInvocation
+from invokeai.app.services.shared.graph import Graph
+
 
 @pytest.fixture
 def patch_rootdir(tmp_path: Path, monkeypatch: Any) -> None:
@@ -158,58 +162,44 @@ def test_type_coercion(patch_rootdir):
     assert isinstance(conf.root, Path)
 
 
-@pytest.mark.xfail(
-    reason="""
-    This test fails when run as part of the full test suite.
-
-    This test needs to deny nodes from being included in the InvocationsUnion by providing
-    an app configuration as a test fixture. Pytest executes all test files before running
-    tests, so the app configuration is already initialized by the time this test runs, and
-    the InvocationUnion is already created and the denied nodes are not omitted from it.
-
-    This test passes when `test_config.py` is tested in isolation.
-
-    Perhaps a solution would be to call `InvokeAIAppConfig.get_config().parse_args()` in
-    other test files?
-    """
-)
 def test_deny_nodes(patch_rootdir):
     from invokeai.app.services.config import InvokeAIAppConfig
 
     # Allow integer, string and float, but explicitly deny float
     allow_deny_nodes_conf = OmegaConf.create(
-        """
+        f"""
         InvokeAI:
           Nodes:
             allow_nodes:
-              - integer
-              - string
-              - float
+              - {IntegerInvocation.get_type()}
+              - {StringInvocation.get_type()}
+              - {FloatInvocation.get_type()}
             deny_nodes:
-              - float
+              - {FloatInvocation.get_type()}
         """
     )
     # must parse config before importing Graph, so its nodes union uses the config
     conf = InvokeAIAppConfig().get_config()
     conf.parse_args(conf=allow_deny_nodes_conf, argv=[])
-    from invokeai.app.services.shared.graph import Graph
 
     # confirm graph validation fails when using denied node
-    Graph(nodes={"1": {"id": "1", "type": "integer"}})
-    Graph(nodes={"1": {"id": "1", "type": "string"}})
+    Graph(nodes={"1": IntegerInvocation(value=1)})
+    Graph(nodes={"1": StringInvocation(value="asdf")})
 
     with pytest.raises(ValidationError):
-        Graph(nodes={"1": {"id": "1", "type": "float"}})
+        Graph(nodes={"1": FloatInvocation(value=1.0)})
 
-    from invokeai.app.invocations.baseinvocation import BaseInvocation
+    # Also test with a dict input
+    with pytest.raises(ValidationError):
+        Graph(nodes={"1": {"id": "1", "type": "float"}})
 
     # confirm invocations union will not have denied nodes
     all_invocations = BaseInvocation.get_invocations()
 
-    has_integer = len([i for i in all_invocations if i.model_fields.get("type").default == "integer"]) == 1
-    has_string = len([i for i in all_invocations if i.model_fields.get("type").default == "string"]) == 1
-    has_float = len([i for i in all_invocations if i.model_fields.get("type").default == "float"]) == 1
+    has_integer = len([i for i in all_invocations if i.get_type() == "integer"]) == 1
+    has_string = len([i for i in all_invocations if i.get_type() == "string"]) == 1
+    does_not_have_float = len([i for i in all_invocations if i.get_type() == "float"]) == 0
 
     assert has_integer
     assert has_string
-    assert not has_float
+    assert does_not_have_float