tests(llm): use pytest monkeypatch for env vars in ssl_verify parsing test

Replaces direct os.environ manipulation with monkeypatch.setenv so env is auto-restored and the test is isolated.

Co-authored-by: openhands <openhands@all-hands.dev>

Author: enyst

tests/sdk/llm/test_llm.py

@@ -1,4 +1,3 @@
-import os
 from typing import Any
 from unittest.mock import Mock, patch
 
@@ -540,32 +539,31 @@ def test_llm_responses_ssl_verify_and_custom_provider(mock_responses):
     assert kwargs.get("api_base") == "https://corporate-proxy.example.com/api"
 
 
-def test_llm_ssl_verify_env_parsing():
-    """Test that ssl_verify is correctly parsed from environment variables."""
+def test_llm_ssl_verify_env_parsing(monkeypatch):
+    """Test that ssl_verify is correctly parsed from environment variables.
+
+    Use pytest's monkeypatch to ensure environment is restored automatically.
+    """
+    # Ensure model is set for all subsequent load_from_env calls
+    monkeypatch.setenv("LLM_MODEL", "gpt-4")
+
     # Test various false values
     for value in ["false", "False", "FALSE", "0", "no", "off"]:
-        os.environ["LLM_SSL_VERIFY"] = value
-        os.environ["LLM_MODEL"] = "gpt-4"
+        monkeypatch.setenv("LLM_SSL_VERIFY", value)
         llm = LLM.load_from_env()
         assert llm.ssl_verify is False, f"Failed for value: {value}"
 
     # Test various true values
     for value in ["true", "True", "TRUE", "1", "yes", "on"]:
-        os.environ["LLM_SSL_VERIFY"] = value
+        monkeypatch.setenv("LLM_SSL_VERIFY", value)
         llm = LLM.load_from_env()
         assert llm.ssl_verify is True, f"Failed for value: {value}"
 
     # Test certificate path (string value)
-    os.environ["LLM_SSL_VERIFY"] = "/path/to/cert.pem"
+    monkeypatch.setenv("LLM_SSL_VERIFY", "/path/to/cert.pem")
     llm = LLM.load_from_env()
     assert llm.ssl_verify == "/path/to/cert.pem"
 
-    # Clean up
-    if "LLM_SSL_VERIFY" in os.environ:
-        del os.environ["LLM_SSL_VERIFY"]
-    if "LLM_MODEL" in os.environ:
-        del os.environ["LLM_MODEL"]
-
 
 def test_llm_vision_support(default_llm):
     """Test LLM vision support detection."""