RAHHH

backend/lib/python3.12/site-packages/twisted/internet/test/test_main.py

@@ -0,0 +1,45 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Tests for L{twisted.internet.main}.
+"""
+
+
+from twisted.internet.error import ReactorAlreadyInstalledError
+from twisted.internet.main import installReactor
+from twisted.internet.test.modulehelpers import NoReactor
+from twisted.trial import unittest
+
+
+class InstallReactorTests(unittest.SynchronousTestCase):
+    """
+    Tests for L{installReactor}.
+    """
+
+    def test_installReactor(self) -> None:
+        """
+        L{installReactor} installs a new reactor if none is present.
+        """
+        with NoReactor():
+            newReactor = object()
+            installReactor(newReactor)
+            from twisted.internet import reactor
+
+            self.assertIs(newReactor, reactor)
+
+    def test_alreadyInstalled(self) -> None:
+        """
+        If a reactor is already installed, L{installReactor} raises
+        L{ReactorAlreadyInstalledError}.
+        """
+        with NoReactor():
+            installReactor(object())
+            self.assertRaises(ReactorAlreadyInstalledError, installReactor, object())
+
+    def test_errorIsAnAssertionError(self) -> None:
+        """
+        For backwards compatibility, L{ReactorAlreadyInstalledError} is an
+        L{AssertionError}.
+        """
+        self.assertTrue(issubclass(ReactorAlreadyInstalledError, AssertionError))