Migrate forward_msg_cache cypress test to playwright (streamlit#7974)

e2e_playwright/conftest.py

@@ -532,3 +532,8 @@ def compare(
 
     if test_failure_messages:
         pytest.fail("Missing snapshots: \n" + "\n".join(test_failure_messages))
+
+
+def rerun(page: Page):
+    page.keyboard.press("r")
+    wait_for_app_run(page)

e2e_playwright/forward_msg_cache_test.py

@@ -0,0 +1,25 @@
+# Copyright (c) Streamlit Inc. (2018-2022) Snowflake Inc. (2022-2024)
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from playwright.sync_api import Page, expect
+
+from e2e_playwright.conftest import rerun
+
+
+def test_forward_msg_cache_receives_msg(app: Page):
+    app.evaluate("window.streamlitDebug.clearForwardMsgCache()")
+    rerun(app)
+    expect(app.get_by_role("dialog")).not_to_be_visible()
+
+    app.expect_request("**/_stcore/message/")