add tpu mocks

Author: justusschock

tests/tests_fabric/graveyard/test_tpu.py

@@ -11,7 +11,7 @@
         ("lightning.fabric.strategies.single_tpu", "SingleTPUStrategy"),
     ],
 )
-def test_graveyard_single_tpu(import_path, name):
+def test_graveyard_single_tpu(import_path, name, tpu_available):
     module = import_module(import_path)
     cls = getattr(module, name)
     device = torch.device("cpu")
@@ -34,7 +34,7 @@ def test_graveyard_single_tpu(import_path, name):
         ("lightning.fabric.plugins.precision.xlabf16", "XLABf16Precision"),
     ],
 )
-def test_graveyard_no_device(import_path, name):
+def test_graveyard_no_device(import_path, name, tpu_available):
     module = import_module(import_path)
     cls = getattr(module, name)
     with pytest.deprecated_call(match="is deprecated"):