Simplify. Every subclass of GPUObjectBase has a device in its _device…

… field.

tests_mem/testutils.py

@@ -215,17 +215,13 @@ def core_test_func():
             cls = objects[0].__class__
             assert all(isinstance(objects[i], cls) for i in range(len(objects)))
 
-            # Test that everything that's a subclass of GPUObjectBase is either a
-            # GPUDevice and has None it its _device field, or is something else and has
-            # a GPUDevice in the _device field.
+            # Test that everything that's a subclass of GPUObjectBase has a device
+            # in its _device field.
             if issubclass(cls, GPUObjectBase):
-                if issubclass(cls, GPUDevice):
-                    assert all(objects[i]._device is None for i in range(len(objects)))
-                else:
-                    assert all(
-                        isinstance(objects[i]._device, GPUDevice)
-                        for i in range(len(objects))
-                    )
+                assert all(
+                    isinstance(objects[i]._device, GPUDevice)
+                    for i in range(len(objects))
+                )
 
             # Test that class matches function name (should prevent a group of copy-paste errors)
             assert ob_name == cls.__name__[3:]

wgpu/_classes.py

@@ -701,7 +701,7 @@ class GPUDevice(GPUObjectBase):
     """
 
     def __init__(self, label, internal, adapter, features, limits, queue):
-        super().__init__(label, internal, None)
+        super().__init__(label, internal, self)
 
         assert isinstance(adapter, GPUAdapter)
         assert isinstance(features, set)