fix: fix unittests.

Author: GdoongMathew

tests/tests_pytorch/accelerators/test_gpu.py

@@ -80,4 +80,4 @@ def test_gpu_device_name():
 
 
 def test_gpu_device_name_no_gpu(cuda_count_0):
-    assert str(False) == CUDAAccelerator.device_name()
+    assert CUDAAccelerator.device_name() == ""

tests/tests_pytorch/accelerators/test_mps.py

@@ -47,7 +47,7 @@ def test_mps_device_name():
 
 def test_mps_device_name_not_available():
     with mock.patch("torch.backends.mps.is_available", return_value=False):
-        assert MPSAccelerator.device_name() == "False"
+        assert MPSAccelerator.device_name() == ""
 
 
 def test_warning_if_mps_not_used(mps_count_1):

tests/tests_pytorch/accelerators/test_xla.py

@@ -304,7 +304,15 @@ def test_warning_if_tpus_not_used(tpu_available):
 
 @RunIf(tpu=True)
 def test_tpu_device_name():
-    assert XLAAccelerator.device_name() == "TPU"
+    from lightning.fabric.accelerators.xla import _XLA_GREATER_EQUAL_2_1
+
+    if _XLA_GREATER_EQUAL_2_1:
+        from torch_xla._internal import tpu
+    else:
+        from torch_xla.experimental import tpu
+    import torch_xla.core.xla_env_vars as xenv
+
+    assert XLAAccelerator.device_name() == tpu.get_tpu_env()[xenv.ACCELERATOR_TYPE]
 
 
 @pytest.mark.parametrize(