[Bugfix] Fix LoRA test (#18518)

Signed-off-by: Jee Jee Li <pandaleefree@gmail.com>

tests/lora/test_lora_functions.py

@@ -69,7 +69,7 @@ def test_lora_functions_sync():
     run_check(llm.add_lora, make_lora_request(12), [12, 9, 10, 11])
     run_check(llm.add_lora, make_lora_request(13), [12, 13, 10, 11])
 
-    # Remove all LoRAs
+    # Remove all LoRAs.
     run_check(llm.remove_lora, 13, [12, 10, 11])
     run_check(llm.remove_lora, 12, [10, 11])
     run_check(llm.remove_lora, 11, [10])

tests/v1/sample/test_topk_topp_sampler.py

@@ -16,9 +16,20 @@ VOCAB_SIZE = 128 * 1024
 FLASHINFER_ENABLED = current_platform.is_cuda() and is_flashinfer_available
 
 
+@pytest.fixture(autouse=True)
+def reset_default_device():
+    """
+    Explicitly set the default device, which can affect subsequent tests. 
+    Adding this fixture helps avoid this problem.
+    """
+    original_device = torch.get_default_device()
+    yield
+    torch.set_default_device(original_device)
+
+
 def test_topk_impl_equivalance():
 
-    with torch.device(DEVICE):
+    torch.set_default_device(DEVICE)
     generator = Generator(device=DEVICE).manual_seed(33)
 
     logits = torch.rand((BATCH_SIZE, VOCAB_SIZE), generator=generator)
@@ -28,10 +39,8 @@ def test_topk_impl_equivalance():
 
     # Set k=vocab_size for ~50% of requests in the batch (top-k disabled).
     k.masked_fill_(
-            torch.randint(0,
-                          2, (BATCH_SIZE, ),
-                          generator=generator,
-                          dtype=bool), VOCAB_SIZE)
+        torch.randint(0, 2, (BATCH_SIZE, ), generator=generator, dtype=bool),
+        VOCAB_SIZE)
 
     # Top-k only implementation
     result1 = apply_top_k_top_p(logits=logits.clone(), k=k, p=None)
@@ -58,7 +67,7 @@ def test_flashinfer_sampler():
         pytest.skip(
             "FlashInfer not installed or not available on this platform.")
 
-    with torch.device(DEVICE):
+    torch.set_default_device(DEVICE)
     generator = Generator(device=DEVICE).manual_seed(42)
 
     # Generate random logits
@@ -67,8 +76,7 @@ def test_flashinfer_sampler():
     # Generate various top-k and top-p values
     k_values = torch.randint(1, 1000, (BATCH_SIZE, ), generator=generator)
     p_values = torch.rand(
-            (BATCH_SIZE, ),
-            generator=generator) * 0.5 + 0.5  # range in [0.5, 1.0]
+        (BATCH_SIZE, ), generator=generator) * 0.5 + 0.5  # range in [0.5, 1.0]
 
     # Sometimes disable top-k (k=vocab_size)
     k_values.masked_fill_(