add cache test

Author: geetu040

tests/test_setups/test_setup_functions.py

@@ -180,4 +180,7 @@ def test_setuplist_offset(self):
 
         assert len(all) == size * 2
 
-
+    @pytest.mark.test_server()
+    def test_get_cached_setup(self):
+        openml.config.set_root_cache_directory(self.static_cache_dir)
+        openml.setups.get_setup(1)