fix(tests): isolate litellm.cache and CLI env vars in flaky tests

- TestSpendLogsPayload: save/restore litellm.cache in setup_method/teardown_method
  so tests that run after a cache-setting test don't see a non-None cache and get
  a hash instead of "Cache OFF" in the cache_key field
- test_use_prisma_db_push_flag_behavior: apply clean_env pattern (strip DATABASE_URL/DIRECT_URL,
  then set DATABASE_URL to test value) inside the with block instead of using @patch.dict
  decorator, matching the pattern from test_skip_server_startup to avoid Click 8.3.x
  StreamMixer stream lifecycle issues in CI

tests/test_litellm/proxy/spend_tracking/test_spend_management_endpoints.py

@@ -1231,9 +1231,12 @@ async def _wait_for_mock_call(mock, timeout=10, interval=0.1):
 class TestSpendLogsPayload:
     def setup_method(self):
         self._original_callbacks = litellm.callbacks[:]
+        self._original_cache = litellm.cache
+        litellm.cache = None
 
     def teardown_method(self):
         litellm.callbacks = self._original_callbacks
+        litellm.cache = self._original_cache
 
     @pytest.mark.asyncio
     async def test_spend_logs_payload_e2e(self):

tests/test_litellm/proxy/test_proxy_cli.py

@@ -586,9 +586,6 @@ class TestHealthAppFactory:
     @patch("litellm.proxy.db.prisma_client.PrismaManager.setup_database")
     @patch("litellm.proxy.db.check_migration.check_prisma_schema_diff")
     @patch("litellm.proxy.db.prisma_client.should_update_prisma_schema")
-    @patch.dict(
-        os.environ, {"DATABASE_URL": "postgresql://test:test@localhost:5432/test"}
-    )
     def test_use_prisma_db_push_flag_behavior(
         self,
         mock_should_update_schema,
@@ -616,7 +613,19 @@ class TestHealthAppFactory:
             save_worker_config=MagicMock(),
         )
 
+        # Strip DIRECT_URL and set DATABASE_URL to a test value so Click's
+        # CliRunner doesn't encounter real DB env vars (causes stream lifecycle
+        # issues with Click 8.3.x in CI environments).
+        clean_env = {
+            k: v
+            for k, v in os.environ.items()
+            if k not in ("DATABASE_URL", "DIRECT_URL")
+        }
+        clean_env["DATABASE_URL"] = "postgresql://test:test@localhost:5432/test"
+
         with patch.dict(
+            os.environ, clean_env, clear=True
+        ), patch.dict(
             "sys.modules",
             {
                 "proxy_server": mock_proxy_module,