Ausgabe der neuen DB Einträge

venv/lib/python3.9/site-packages/twisted/internet/test/_yieldfromtests.py.3only

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+# -*- test-case-name: twisted.internet.test.test_coroutines -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Tests for C{yield from} support in Deferreds.
+
+These tests can only work and be imported on Python 3!
+"""
+
+import types
+
+from twisted.internet.defer import Deferred, ensureDeferred, fail
+from twisted.trial.unittest import TestCase
+from twisted.internet.task import Clock
+
+
+class YieldFromTests(TestCase):
+    """
+    Tests for using Deferreds in conjunction with PEP-380.
+    """
+
+    def test_ensureDeferred(self):
+        """
+        L{ensureDeferred} will turn a coroutine into a L{Deferred}.
+        """
+        def run():
+            d = Deferred()
+            d.callback("bar")
+            yield from d
+            res = yield from run2()
+            return res
+
+        def run2():
+            d = Deferred()
+            d.callback("foo")
+            res = yield from d
+            return res
+
+        # It's a generator...
+        r = run()
+        self.assertIsInstance(r, types.GeneratorType)
+
+        # Now it's a Deferred.
+        d = ensureDeferred(r)
+        self.assertIsInstance(d, Deferred)
+
+        # The Deferred has the result we want.
+        res = self.successResultOf(d)
+        self.assertEqual(res, "foo")
+
+
+    def test_basic(self):
+        """
+        L{ensureDeferred} allows a function to C{yield from} a L{Deferred}.
+        """
+        def run():
+            d = Deferred()
+            d.callback("foo")
+            res = yield from d
+            return res
+
+        d = ensureDeferred(run())
+        res = self.successResultOf(d)
+        self.assertEqual(res, "foo")
+
+
+    def test_exception(self):
+        """
+        An exception in a generator wrapped with L{ensureDeferred} will cause
+        the returned L{Deferred} to fire with a failure.
+        """
+        def run():
+            d = Deferred()
+            d.callback("foo")
+            yield from d
+            raise ValueError("Oh no!")
+
+        d = ensureDeferred(run())
+        res = self.failureResultOf(d)
+        self.assertEqual(type(res.value), ValueError)
+        self.assertEqual(res.value.args, ("Oh no!",))
+
+
+    def test_twoDeep(self):
+        """
+        An exception in a generator wrapped with L{ensureDeferred} will cause
+        the returned L{Deferred} to fire with a failure.
+        """
+        reactor = Clock()
+        sections = []
+
+        def runone():
+            sections.append(2)
+            d = Deferred()
+            reactor.callLater(1, d.callback, None)
+            yield from d
+            sections.append(3)
+            return "Yay!"
+
+
+        def run():
+            sections.append(1)
+            result = yield from runone()
+            sections.append(4)
+            d = Deferred()
+            reactor.callLater(1, d.callback, None)
+            yield from d
+            sections.append(5)
+            return result
+
+        d = ensureDeferred(run())
+
+        reactor.advance(0.9)
+        self.assertEqual(sections, [1, 2])
+
+        reactor.advance(0.1)
+        self.assertEqual(sections, [1, 2, 3, 4])
+
+        reactor.advance(0.9)
+        self.assertEqual(sections, [1, 2, 3, 4])
+
+        reactor.advance(0.1)
+        self.assertEqual(sections, [1, 2, 3, 4, 5])
+
+        res = self.successResultOf(d)
+        self.assertEqual(res, "Yay!")
+
+
+    def test_reraise(self):
+        """
+        Yielding from an already failed Deferred will raise the exception.
+        """
+        def test():
+            try:
+                yield from fail(ValueError("Boom"))
+            except ValueError as e:
+                self.assertEqual(e.args, ("Boom",))
+                return 1
+            return 0
+
+        res = self.successResultOf(ensureDeferred(test()))
+        self.assertEqual(res, 1)
+
+
+    def test_chained(self):
+        """
+        Yielding from a paused & chained Deferred will give the result when it
+        has one.
+        """
+        reactor = Clock()
+
+        def test():
+            d = Deferred()
+            d2 = Deferred()
+            d.addCallback(lambda ignored: d2)
+
+            d.callback(None)
+            reactor.callLater(0, d2.callback, "bye")
+            res = yield from d
+            return res
+
+        d = ensureDeferred(test())
+        reactor.advance(0.1)
+
+        res = self.successResultOf(d)
+        self.assertEqual(res, "bye")