fix: run Shiny E2E apps as subprocesses (demonstrate shinychat main issue)

pkg-py/tests/playwright/conftest.py

@@ -14,6 +14,7 @@
 from typing import TYPE_CHECKING, Any
 
 import pytest
+from shiny.pytest import create_app_fixture
 
 # Configure logging for test debugging
 logger = logging.getLogger(__name__)
@@ -150,82 +151,11 @@ def _create_chat_controller(page: Page, table_name: str) -> ChatControllerType:
     return ChatController(page, f"querychat_{table_name}-chat")
 
 
-def _load_shiny_app(app_path: str) -> Any:
-    """
-    Load a Shiny app from a Python file.
-
-    Handles both Shiny Core apps (with explicit `app = App(...)`) and Shiny Express
-    apps (which use decorators and don't have an explicit app object).
-
-    Args:
-        app_path: Absolute or relative path to the Shiny app Python file.
-
-    Returns:
-        The loaded Shiny App object ready to be served.
-
-    Note:
-        Uses unique module names based on the file path to avoid Python's module
-        caching, which could cause issues when loading multiple apps in the same
-        test session.
-
-    """
-    from shiny.express._is_express import is_express_app
-    from shiny.express._run import wrap_express_app
-
-    path = Path(app_path).resolve()
-    app_dir = str(path.parent)
-    app_file = path.name
-
-    if is_express_app(app_file, app_dir):
-        # Express apps don't have an explicit `app` object
-        return wrap_express_app(path)
-    else:
-        # Regular apps have `app = App(...)` at module level
-        # Use unique module name based on path to avoid caching issues
-        module_name = f"shiny_app_{path.stem}_{id(path)}"
-        spec = importlib.util.spec_from_file_location(module_name, str(path))
-        module = importlib.util.module_from_spec(spec)  # type: ignore[arg-type]
-        spec.loader.exec_module(module)  # type: ignore[union-attr]
-        return module.app
-
-
-def _start_shiny_app_threaded(app_path: str, port: int) -> tuple[threading.Thread, Any]:
-    """Start a Shiny app in a background thread."""
-    import uvicorn
-
-    app = _load_shiny_app(app_path)
-    config = uvicorn.Config(app, host="127.0.0.1", port=port, log_level="warning")
-    server = uvicorn.Server(config)
-    thread = threading.Thread(target=server.run, daemon=True)
-    thread.start()
-    return thread, server
-
-
-def _stop_shiny_server(server: Any) -> None:
-    """Stop a uvicorn server."""
-    server.should_exit = True
-
-
-@pytest.fixture(scope="module")
-def app_01_hello() -> Generator[str, None, None]:
-    """Start the 01-hello-app.py Shiny server for testing."""
-    app_path = str(EXAMPLES_DIR / "01-hello-app.py")
-
-    def start_factory():
-        port = _find_free_port()
-        url = f"http://localhost:{port}"
-        return url, lambda: _start_shiny_app_threaded(app_path, port)
-
-    def shiny_cleanup(_thread, server):
-        _stop_shiny_server(server)
-
-    url, _thread, server = _start_server_with_retry(
-        start_factory, shiny_cleanup, timeout=30.0
-    )
-    try:
-        yield url
-    finally:
-        _stop_shiny_server(server)
+# Shiny apps run as subprocesses via shiny.pytest.create_app_fixture.
+# Running them in-process (threaded uvicorn) shares Shiny's process-global,
+# loop-bound reactive lock across apps, which crashes sessions when apps
+# on different event loops contend for it.
+app_01_hello = create_app_fixture(EXAMPLES_DIR / "01-hello-app.py", scope="module")
 
 
 @pytest.fixture
@@ -234,26 +164,7 @@ def chat_01_hello(page: Page) -> ChatControllerType:
     return _create_chat_controller(page, "titanic")
 
 
-@pytest.fixture(scope="module")
-def app_02_prompt() -> Generator[str, None, None]:
-    """Start the 02-prompt-app.py Shiny server for testing."""
-    app_path = str(EXAMPLES_DIR / "02-prompt-app.py")
-
-    def start_factory():
-        port = _find_free_port()
-        url = f"http://localhost:{port}"
-        return url, lambda: _start_shiny_app_threaded(app_path, port)
-
-    def shiny_cleanup(_thread, server):
-        _stop_shiny_server(server)
-
-    url, _thread, server = _start_server_with_retry(
-        start_factory, shiny_cleanup, timeout=30.0
-    )
-    try:
-        yield url
-    finally:
-        _stop_shiny_server(server)
+app_02_prompt = create_app_fixture(EXAMPLES_DIR / "02-prompt-app.py", scope="module")
 
 
 @pytest.fixture
@@ -262,26 +173,9 @@ def chat_02_prompt(page: Page) -> ChatControllerType:
     return _create_chat_controller(page, "titanic")
 
 
-@pytest.fixture(scope="module")
-def app_03_express() -> Generator[str, None, None]:
-    """Start the 03-sidebar-express-app.py Shiny server for testing."""
-    app_path = str(EXAMPLES_DIR / "03-sidebar-express-app.py")
-
-    def start_factory():
-        port = _find_free_port()
-        url = f"http://localhost:{port}"
-        return url, lambda: _start_shiny_app_threaded(app_path, port)
-
-    def shiny_cleanup(_thread, server):
-        _stop_shiny_server(server)
-
-    url, _thread, server = _start_server_with_retry(
-        start_factory, shiny_cleanup, timeout=30.0
-    )
-    try:
-        yield url
-    finally:
-        _stop_shiny_server(server)
+app_03_express = create_app_fixture(
+    EXAMPLES_DIR / "03-sidebar-express-app.py", scope="module"
+)
 
 
 @pytest.fixture
@@ -290,26 +184,9 @@ def chat_03_express(page: Page) -> ChatControllerType:
     return _create_chat_controller(page, "titanic")
 
 
-@pytest.fixture(scope="module")
-def app_03_core() -> Generator[str, None, None]:
-    """Start the 03-sidebar-core-app.py Shiny server for testing."""
-    app_path = str(EXAMPLES_DIR / "03-sidebar-core-app.py")
-
-    def start_factory():
-        port = _find_free_port()
-        url = f"http://localhost:{port}"
-        return url, lambda: _start_shiny_app_threaded(app_path, port)
-
-    def shiny_cleanup(_thread, server):
-        _stop_shiny_server(server)
-
-    url, _thread, server = _start_server_with_retry(
-        start_factory, shiny_cleanup, timeout=30.0
-    )
-    try:
-        yield url
-    finally:
-        _stop_shiny_server(server)
+app_03_core = create_app_fixture(
+    EXAMPLES_DIR / "03-sidebar-core-app.py", scope="module"
+)
 
 
 @pytest.fixture
@@ -605,26 +482,7 @@ def dash_cleanup(_thread, server):
         _stop_dash_server(server)
 
 
-@pytest.fixture(scope="module")
-def app_10_viz() -> Generator[str, None, None]:
-    """Start the 10-viz-app.py Shiny server for testing."""
-    app_path = str(EXAMPLES_DIR / "10-viz-app.py")
-
-    def start_factory():
-        port = _find_free_port()
-        url = f"http://localhost:{port}"
-        return url, lambda: _start_shiny_app_threaded(app_path, port)
-
-    def shiny_cleanup(_thread, server):
-        _stop_shiny_server(server)
-
-    url, _thread, server = _start_server_with_retry(
-        start_factory, shiny_cleanup, timeout=30.0
-    )
-    try:
-        yield url
-    finally:
-        _stop_shiny_server(server)
+app_10_viz = create_app_fixture(EXAMPLES_DIR / "10-viz-app.py", scope="module")
 
 
 @pytest.fixture

pkg-py/tests/playwright/test_01_hello_app.py

@@ -15,6 +15,7 @@
 
 if TYPE_CHECKING:
     from playwright.sync_api import Page
+    from shiny.run import ShinyAppProc
     from shinychat.playwright import ChatController
 
 
@@ -23,10 +24,10 @@ class Test01HelloApp:
 
     @pytest.fixture(autouse=True)
     def setup(
-        self, page: Page, app_01_hello: str, chat_01_hello: ChatController
+        self, page: Page, app_01_hello: ShinyAppProc, chat_01_hello: ChatController
     ) -> None:
         """Navigate to the app before each test."""
-        page.goto(app_01_hello)
+        page.goto(app_01_hello.url)
         page.wait_for_selector("table", timeout=10000)
         self.page = page
         self.chat = chat_01_hello
@@ -244,7 +245,7 @@ def test_stop_button_appears_during_streaming(self) -> None:
         )
         self.chat.send_user_input(method="click")
 
-        stop_btn = self.page.locator(".shiny-chat-btn-cancel")
+        stop_btn = self.page.locator('.shiny-chat-btn-send[data-state="cancel"]')
         expect(stop_btn).to_be_visible(timeout=30000)
 
     def test_cancel_stops_response(self) -> None:
@@ -255,7 +256,7 @@ def test_cancel_stops_response(self) -> None:
         )
         self.chat.send_user_input(method="click")
 
-        stop_btn = self.page.locator(".shiny-chat-btn-cancel")
+        stop_btn = self.page.locator('.shiny-chat-btn-send[data-state="cancel"]')
         expect(stop_btn).to_be_visible(timeout=30000)
         stop_btn.click()
 
@@ -271,7 +272,7 @@ def test_can_send_after_cancel(self) -> None:
         )
         self.chat.send_user_input(method="click")
 
-        stop_btn = self.page.locator(".shiny-chat-btn-cancel")
+        stop_btn = self.page.locator('.shiny-chat-btn-send[data-state="cancel"]')
         expect(stop_btn).to_be_visible(timeout=30000)
         stop_btn.click()
 
@@ -281,5 +282,7 @@ def test_can_send_after_cancel(self) -> None:
         self.chat.set_user_input("How many rows are in the dataset?")
         self.chat.send_user_input(method="click")
 
-        send_btn = self.page.locator(".shiny-chat-btn-send:not(.shiny-chat-btn-cancel)")
+        send_btn = self.page.locator(
+            '.shiny-chat-btn-send:not([data-state="cancel"]):not([data-state="cancelling"])'
+        )
         expect(send_btn).to_be_visible(timeout=60000)

pkg-py/tests/playwright/test_02_prompt_app.py

@@ -14,6 +14,7 @@
 
 if TYPE_CHECKING:
     from playwright.sync_api import Page
+    from shiny.run import ShinyAppProc
     from shinychat.playwright import ChatController
 
 
@@ -22,10 +23,10 @@ class Test02PromptApp:
 
     @pytest.fixture(autouse=True)
     def setup(
-        self, page: Page, app_02_prompt: str, chat_02_prompt: ChatController
+        self, page: Page, app_02_prompt: ShinyAppProc, chat_02_prompt: ChatController
     ) -> None:
         """Navigate to the app before each test."""
-        page.goto(app_02_prompt)
+        page.goto(app_02_prompt.url)
         page.wait_for_selector("table", timeout=10000)
         self.page = page
         self.chat = chat_02_prompt

pkg-py/tests/playwright/test_03_sidebar_apps.py

@@ -17,6 +17,7 @@
 
 if TYPE_CHECKING:
     from playwright.sync_api import Page
+    from shiny.run import ShinyAppProc
     from shinychat.playwright import ChatController
 
 
@@ -25,10 +26,10 @@ class Test03SidebarExpress:
 
     @pytest.fixture(autouse=True)
     def setup(
-        self, page: Page, app_03_express: str, chat_03_express: ChatController
+        self, page: Page, app_03_express: ShinyAppProc, chat_03_express: ChatController
     ) -> None:
         """Navigate to the app before each test."""
-        page.goto(app_03_express)
+        page.goto(app_03_express.url)
         # Wait for data table to be visible
         page.wait_for_selector("table tbody tr", timeout=15000)
         self.page = page
@@ -114,9 +115,11 @@ class Test03SidebarCore:
     """Tests for 03-sidebar-core-app.py - Shiny Core with sidebar layout."""
 
     @pytest.fixture(autouse=True)
-    def setup(self, page: Page, app_03_core: str, chat_03_core: ChatController) -> None:
+    def setup(
+        self, page: Page, app_03_core: ShinyAppProc, chat_03_core: ChatController
+    ) -> None:
         """Navigate to the app before each test."""
-        page.goto(app_03_core)
+        page.goto(app_03_core.url)
         # Wait for Shiny data frame to be ready (uses shiny-data-frame custom element)
         page.wait_for_selector("shiny-data-frame table", timeout=15000)
         self.page = page