fix: pass import path instead of callable in 'screenshot_apps'

.github/workflows/unit-test.yml

@@ -28,3 +28,10 @@ jobs:
         run: playwright install
       - name: Run unittest
         run: pytest
+      - name: Upload failed image artifact
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: failed-images-${{ matrix.os }}-${{ matrix.python-version }}
+          # https://docs.pytest.org/en/stable/how-to/tmp_path.html#temporary-directory-location-and-retention
+          path: /tmp/pytest-of-*/pytest-*/*/*/*.obtained.png

README.md

@@ -65,25 +65,28 @@ It also generates a PDF file when `pdf` option is given, which might be useful w
 ## Local WSGI application
 
 `sphinxcontrib-screenshot` can launch your local WSGI applications and take screenshot of thems.
-Define them in the `screenshot_apps` dict. The key must be a name you choose for your applications, and the value must be a callable that creates a WSGI app:
+Define them in the `screenshot_apps` dict.
+The key must be a name you choose for your applications, and the value must be a callable that creates a WSGI app:
 
 ```python
 from flask import Flask
 
-def create_app():
+def create_app(sphinx_app):
     app = Flask(__name__)
 
     @app.route("/hello")
     def hello():
         return "Hello, world!"
 
     return app
+```
 
-
+```
 screenshot_apps = {
-    "example": create_app,
+    "example": "my_module.my_app:create_app",
 }
 ```
+Note that you might manually add your application module in `sys.path`.
 
 Then you can use a Sphinx substitution with your application name to refer to its temporary URL:
 

setup.cfg

@@ -36,7 +36,7 @@ dev =
     mypy
     Pillow
     pytest
-    pytest-regressions
+    pytest-regressions[image]
     sphinx[test]
     toml
     twine

sphinxcontrib/screenshot.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import hashlib
+import importlib
 import os
 import threading
 import typing
@@ -208,20 +209,28 @@ def run(self) -> typing.List[nodes.Node]:
 app_threads = {}
 
 
+def resolve_wsgi_app_import(app: Sphinx, app_path: str):
+  module_path, app_attribute = app_path.split(":")
+  module = importlib.import_module(module_path)
+  app_attr = getattr(module, app_attribute)
+  wsgi_app = app_attr(app) if callable(app_attr) else app_attr
+  return wsgi_app
+
+
 def setup_apps(app: Sphinx, config: Config):
   """Start the WSGI application threads.
 
     A new replacement is created for each WSGI app."""
-  for app_name, app_builder in config.screenshot_apps.items():
+  for wsgi_app_name, wsgi_app_path in config.screenshot_apps.items():
     port = pick_unused_port()
     config.rst_prolog = (
         config.rst_prolog or
-        "") + f".. |{app_name}| replace:: http://localhost:{port}\n"
-    wsgi_app = app_builder()
+        "") + f"\n.. |{wsgi_app_name}| replace:: http://localhost:{port}\n"
+    wsgi_app = resolve_wsgi_app_import(app, wsgi_app_path)
     httpd = wsgiref.simple_server.make_server("localhost", port, wsgi_app)
     thread = threading.Thread(target=httpd.serve_forever)
     thread.start()
-    app_threads[app_name] = (httpd, thread)
+    app_threads[wsgi_app_name] = (httpd, thread)
 
 
 def teardown_apps(app: Sphinx, exception: typing.Optional[Exception]):

tests/roots/test-wsgi-apps/conf.py

@@ -11,11 +11,10 @@
 # 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.
-def hello_world_app(environ, start_response):
-  headers = [('Content-type', 'text/plain; charset=utf-8')]
-  start_response('200 OK', headers)
-  return [b'Hello, World!']
+import pathlib
+import sys
 
+sys.path.insert(0, str(pathlib.Path(__file__).parent.resolve()))
 
 extensions = ['sphinxcontrib.screenshot']
-screenshot_apps = {"example": lambda: hello_world_app}
+screenshot_apps = {"example": "example_app:create_app"}

tests/roots/test-wsgi-apps/example_app.py

@@ -0,0 +1,25 @@
+# Copyright 2024 Google LLC
+#
+# 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.
+def create_app(sphinx_app):
+
+  def hello_world_app(environ, start_response):
+    headers = [('Content-type', 'text/html; charset=utf-8')]
+    start_response('200 OK', headers)
+    style = b"font-family: arial; font-size: 10px; margin: 0; padding: 0"
+    return [
+        b"<html>" + b'<body style="' + style + b'">' + b"Hello, World!" +
+        b"</body>" + b"</html>"
+    ]
+
+  return hello_world_app

tests/roots/test-wsgi-apps/index.rst

@@ -1 +1,3 @@
 .. screenshot:: |example|
+   :width: 800
+   :height: 600

tests/test_wsgi_apps.py

@@ -20,7 +20,7 @@
 
 @pytest.mark.sphinx('html', testroot="wsgi-apps")
 def test_default(app: SphinxTestApp, status: StringIO, warning: StringIO,
-                 data_regression) -> None:
+                 image_regression) -> None:
   app.build()
   out_html = app.outdir / "index.html"
 
@@ -29,4 +29,4 @@ def test_default(app: SphinxTestApp, status: StringIO, warning: StringIO,
 
   img_path = app.outdir / imgs[0]['src']
   with open(img_path, "rb") as fd:
-    data_regression.check(fd.read())
+    image_regression.check(fd.read())