Fix twisted plugin installation with new packaging. (#562)

* Added test for twisted plugin installation.

Refs #557.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Fixed setuptools configuration

Port correct configuration from old setup.cfg file.

Regression in #542. Fixes #557.

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

pyproject.toml

@@ -55,7 +55,7 @@ requires = ["setuptools"]
 build-backend = "setuptools.build_meta"
 
 [tool.setuptools]
-packages = ["daphne"]
+package-dir = { daphne = "daphne", twisted = "daphne/twisted" }
 
 [tool.setuptools.dynamic]
 version = { attr = "daphne.__version__" }

tests/test_packaging.py

@@ -0,0 +1,15 @@
+import sys
+from pathlib import Path
+
+
+def test_fd_endpoint_plugin_installed():
+    # Find the site-packages directory
+    for path in sys.path:
+        if "site-packages" in path:
+            site_packages = Path(path)
+            break
+    else:
+        raise AssertionError("Could not find site-packages in sys.path")
+
+    plugin_path = site_packages / "twisted" / "plugins" / "fd_endpoint.py"
+    assert plugin_path.exists(), f"fd_endpoint.py not found at {plugin_path}"