removed side effect in tests

Author: yujinwunz

tests/unit/test_resources.py

@@ -1,7 +1,6 @@
 import mock
 import dash
 from dash import dcc, html  # noqa: F401
-import sys
 
 from dash.development.base_component import ComponentRegistry
 
@@ -112,15 +111,14 @@ def test_collect_and_register_resources(mocker):
     )
     with mock.patch("dash.dash.os.stat", return_value=StatMock()):
         with mock.patch("dash.dash.importlib.import_module") as import_mock:
-            sys.modules["dash_html_components"] = dcc
-
-            import_mock.return_value = dcc
-            app._collect_and_register_resources(
-                [
-                    {
-                        "namespace": "dash_html_components",
-                        "relative_package_path": "dash_html_components.min.js",
-                    },
-                ]
-            )
-            import_mock.assert_any_call("dash_html_components")
+            with mock.patch("sys.modules", {"dash_html_components": dcc}):
+                import_mock.return_value = dcc
+                app._collect_and_register_resources(
+                    [
+                        {
+                            "namespace": "dash_html_components",
+                            "relative_package_path": "dash_html_components.min.js",
+                        },
+                    ]
+                )
+                import_mock.assert_any_call("dash_html_components")