Added test for twisted plugin installation.

Refs #557.

Author: carltongibson

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}"