fix(tests): dynamically determine the path to the shiny app

CHANGELOG.md

@@ -22,7 +22,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Expose `shiny.playwright`, `shiny.run`, and `shiny.pytest` modules that allow users to testing their Shiny apps.  (#1448, #1456, #1481)
   * `shiny.playwright` contains `controller` and `expect` submodules. `controller` will contain many classes to interact with (and verify!) your Shiny app using Playwright. `expect` contains expectation functions that enhance standard Playwright expectation methods.
   * `shiny.run` contains the `run_shiny_app` command and the return type `ShinyAppProc`. `ShinyAppProc` can be used to type the Shiny app pytest fixtures.
-  * `shiny.pytest` contains pytest test fixtures. The `local_app` pytest fixture is automatically available and runs a sibling `app.py` file. Where as `create_app_fixture(PATH_TO_APP)` allows for a Shiny app to be instantiated from a different folder.
+  * `shiny.pytest` contains pytest test fixtures. The `local_app` pytest fixture is automatically available and runs a sibling `app.py` file. Where as `create_app_fixture(PATH_TO_APP)` allows for a relative path to a Shiny app to be instantiated from a different folder.
 
 * Added CLI command `shiny add test` to add a test file to an existing Shiny app. (#1461)
 

shiny/pytest/_fixture.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from pathlib import PurePath
+from pathlib import Path, PurePath
 from typing import Literal, Union
 
 import pytest
@@ -29,13 +29,22 @@ def create_app_fixture(
     ----------
     app
         The path to the Shiny app file.
+
+        If `app` is a `Path` or `PurePath` instance and `.is_file()` returns `True`, then this value will be used directly.
+        Note, file paths will be checked from where `pytest` was called, not from the calling function.
+
+        Otherwise, all `app` paths will be considered to be relative paths from where the test function was collected.
+
+        To be sure that your app path is always relative, supply a `str` value.
     scope
         The scope of the fixture.
     """
 
     @pytest.fixture(scope=scope)
-    def fixture_func():
-        sa_gen = shiny_app_gen(app)
+    def fixture_func(request: pytest.FixtureRequest):
+        app_purepath_exists = isinstance(app, PurePath) and Path(app).is_file()
+        app_path = app if app_purepath_exists else request.path.parent / app
+        sa_gen = shiny_app_gen(app_path)
         yield next(sa_gen)
 
     return fixture_func