Merge pull request #34 from altendky/31-altendky-async_callbacks

[31] Add @ensureDeferred for use with async/await

Author: altendky

README.rst

@@ -51,7 +51,7 @@ is to ``import pytest_twisted as pt``.
 
 
 inlineCallbacks
-=================
+===============
 Using ``twisted.internet.defer.inlineCallbacks`` as a decorator for test
 functions, which take funcargs, does not work. Please use
 ``pytest_twisted.inlineCallbacks`` instead::
@@ -61,6 +61,19 @@ functions, which take funcargs, does not work. Please use
       res = yield threads.deferToThread(os.listdir, tmpdir.strpath)
       assert res == []
 
+
+ensureDeferred
+==============
+Using ``twisted.internet.defer.ensureDeferred`` as a decorator for test
+functions, which take funcargs, does not work. Please use
+``pytest_twisted.ensureDeferred`` instead::
+
+  @pytest_twisted.ensureDeferred
+  async def test_some_stuff(tmpdir):
+      res = await threads.deferToThread(os.listdir, tmpdir.strpath)
+      assert res == []
+
+
 Waiting for deferreds in fixtures
 =================================
 ``pytest_twisted.blockon`` allows fixtures to wait for deferreds::

pytest_twisted.py

@@ -61,6 +61,11 @@ def inlineCallbacks(fun, *args, **kw):
     return defer.inlineCallbacks(fun)(*args, **kw)
 
 
+@decorator.decorator
+def ensureDeferred(fun, *args, **kw):
+    return defer.ensureDeferred(fun(*args, **kw))
+
+
 def init_twisted_greenlet():
     if _instances.reactor is None or _instances.gr_twisted:
         return

testing/test_basic.py

@@ -3,6 +3,11 @@
 
 import pytest
 
+import pytest_twisted
+
+
+ASYNC_AWAIT = sys.version_info >= (3, 5)
+
 
 def assert_outcomes(run_result, outcomes):
     formatted_output = format_run_result_output_for_assert(run_result)
@@ -35,6 +40,13 @@ def skip_if_reactor_not(request, expected_reactor):
         pytest.skip("reactor is {} not {}".format(actual_reactor, expected_reactor))
 
 
+def skip_if_no_async_await():
+    return pytest.mark.skipif(
+        not ASYNC_AWAIT,
+        reason="async/await syntax not supported on Python <3.5",
+    )
+
+
 @pytest.fixture
 def cmd_opts(request):
     reactor = request.config.getoption("reactor", "default")
@@ -126,6 +138,28 @@ def test_succeed(foo):
     assert_outcomes(rr, {"passed": 2, "failed": 1})
 
 
+@skip_if_no_async_await()
+def test_async_await(testdir, cmd_opts):
+    test_file = """
+    from twisted.internet import reactor, defer
+    import pytest
+    import pytest_twisted
+
+    @pytest.fixture(scope="module", params=["fs", "imap", "web"])
+    def foo(request):
+        return request.param
+
+    @pytest_twisted.ensureDeferred
+    async def test_succeed(foo):
+        await defer.succeed(foo)
+        if foo == "web":
+            raise RuntimeError("baz")
+    """
+    testdir.makepyfile(test_file)
+    rr = testdir.run(sys.executable, "-m", "pytest", "-v", *cmd_opts)
+    assert_outcomes(rr, {"passed": 2, "failed": 1})
+
+
 def test_twisted_greenlet(testdir, cmd_opts):
     test_file = """
     import pytest, greenlet
@@ -171,6 +205,32 @@ def test_succeed(foo):
     assert_outcomes(rr, {"passed": 2, "failed": 1})
 
 
+@skip_if_no_async_await()
+def test_blockon_in_fixture_async(testdir, cmd_opts):
+    test_file = """
+    from twisted.internet import reactor, defer
+    import pytest
+    import pytest_twisted
+
+    @pytest.fixture(scope="module", params=["fs", "imap", "web"])
+    def foo(request):
+        d1, d2 = defer.Deferred(), defer.Deferred()
+        reactor.callLater(0.01, d1.callback, 1)
+        reactor.callLater(0.02, d2.callback, request.param)
+        pytest_twisted.blockon(d1)
+        return d2
+
+    @pytest_twisted.ensureDeferred
+    async def test_succeed(foo):
+        x = await foo
+        if x == "web":
+            raise RuntimeError("baz")
+    """
+    testdir.makepyfile(test_file)
+    rr = testdir.run(sys.executable, "-m", "pytest", "-v", *cmd_opts)
+    assert_outcomes(rr, {"passed": 2, "failed": 1})
+
+
 def test_blockon_in_hook(testdir, cmd_opts, request):
     skip_if_reactor_not(request, "default")
     conftest_file = """