Use monkeypatch to set env var in test

Signed-off-by: Pooya Davoodi <[email protected]>

Author: pooyadavoodi

tests/models/embedding/language/test_gritlm.py

@@ -1,6 +1,5 @@
 import importlib.util
 import math
-import os
 from array import array
 from typing import List
 
@@ -17,10 +16,8 @@
 # GritLM embedding implementation is only supported by XFormers backend.
 pytest.mark.skipif(not importlib.util.find_spec("xformers"),
                    reason="GritLM requires XFormers")
-os.environ["VLLM_ATTENTION_BACKEND"] = "XFORMERS"
 
 MODEL_NAME = "parasail-ai/GritLM-7B-vllm"
-
 MAX_MODEL_LEN = 4000
 
 
@@ -31,7 +28,10 @@ def _arr(arr):
     return array("i", arr)
 
 
-def test_find_array():
+def test_find_array(monkeypatch):
+    # GritLM embedding implementation is only supported by XFormers backend.
+    monkeypatch.setenv("VLLM_ATTENTION_BACKEND", "XFORMERS")
+
     from vllm.model_executor.models.gritlm import GritLMPooler
 
     # Create an LLM object to get the model config.
@@ -51,9 +51,13 @@ def test_find_array():
 
 @pytest.fixture(scope="module")
 def server_embedding():
-    args = ["--task", "embedding", "--max_model_len", str(MAX_MODEL_LEN)]
-    with RemoteOpenAIServer(MODEL_NAME, args) as remote_server:
-        yield remote_server
+    # GritLM embedding implementation is only supported by XFormers backend.
+    with pytest.MonkeyPatch.context() as mp:
+        mp.setenv("VLLM_ATTENTION_BACKEND", "XFORMERS")
+
+        args = ["--task", "embedding", "--max_model_len", str(MAX_MODEL_LEN)]
+        with RemoteOpenAIServer(MODEL_NAME, args) as remote_server:
+            yield remote_server
 
 
 @pytest.fixture(scope="module")
@@ -131,7 +135,10 @@ def validate_embed_output(q_rep: List[float], d_rep: List[float]):
     assert math.isclose(cosine_sim_q1_d1, 0.532, abs_tol=0.001)
 
 
-def test_gritlm_offline_embedding():
+def test_gritlm_offline_embedding(monkeypatch):
+    # GritLM embedding implementation is only supported by XFormers backend.
+    monkeypatch.setenv("VLLM_ATTENTION_BACKEND", "XFORMERS")
+
     queries, q_instruction, documents, d_instruction = get_test_data()
 
     llm = vllm.LLM(MODEL_NAME, task="embedding", max_model_len=MAX_MODEL_LEN)