[Attention] Update tests to remove deprecated env vars (#30563)

Signed-off-by: Matthew Bonanni <mbonanni@redhat.com>

tests/v1/cudagraph/test_cudagraph_mode.py

@@ -1,7 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-import contextlib
-import os
 import weakref
 from contextlib import ExitStack
 
@@ -13,26 +11,6 @@ from vllm import LLM
 from vllm.config import CompilationConfig, CompilationMode
 from vllm.platforms import current_platform
 
-
-@contextlib.contextmanager
-def temporary_environ(env_vars):
-    """
-    Temporarily set environment variables and restore them afterward.
-    We have to do this vs monkeypatch because monkeypatch doesn't work
-    with "module" scoped fixtures.
-    """
-    original_env = {k: os.environ.get(k) for k in env_vars}
-    try:
-        os.environ.update(env_vars)
-        yield
-    finally:
-        for k, v in original_env.items():
-            if v is None:
-                os.environ.pop(k, None)
-            else:
-                os.environ[k] = v
-
-
 # test attention backend and cudagraph_mode combo
 # (backend_name, cudagraph_mode, supported)
 if current_platform.is_rocm():
@@ -68,9 +46,9 @@ def test_backend_and_cudagraph_mode_combo(backend_name, cudagraph_mode, supporte
     ):
         pytest.skip("Only Hopper GPUs support FA3 and FlashMLA")
 
-    env_vars = backend_configs[backend_name].env_vars
+    attention_config = backend_config.attention_config
 
-    with temporary_environ(env_vars), ExitStack() as stack:
+    with ExitStack() as stack:
         if not supported:
             stack.enter_context(pytest.raises(Exception))
 
@@ -80,6 +58,7 @@ def test_backend_and_cudagraph_mode_combo(backend_name, cudagraph_mode, supporte
             trust_remote_code=True,
             gpu_memory_utilization=0.45,
             max_model_len=1024,
+            attention_config=attention_config,
             compilation_config=CompilationConfig(
                 mode=CompilationMode.VLLM_COMPILE, cudagraph_mode=cudagraph_mode
             ),
@@ -122,9 +101,10 @@ combo_cases_2 = [
 def test_cudagraph_compilation_combo(
     backend_name, cudagraph_mode, compilation_mode, supported
 ):
-    env_vars = backend_configs[backend_name].env_vars
+    backend_config = backend_configs[backend_name]
+    attention_config = backend_config.attention_config
 
-    with temporary_environ(env_vars), ExitStack() as stack:
+    with ExitStack() as stack:
         if not supported:
             stack.enter_context(pytest.raises(Exception))
 
@@ -134,6 +114,7 @@ def test_cudagraph_compilation_combo(
             trust_remote_code=True,
             gpu_memory_utilization=0.45,
             max_model_len=1024,
+            attention_config=attention_config,
             compilation_config=CompilationConfig(
                 mode=compilation_mode, cudagraph_mode=cudagraph_mode
             ),