[pygobject/benzea/gio-asyncio: 8/10] tests: Add tests for awaitable return of async routines

[Benjamin Berg <bberg src gnome org>]

commit d9492a042603f06348348f2d950ecee879221de9
Author: Benjamin Berg <bberg redhat com>
Date:   Fri Nov 26 13:31:38 2021 +0100

    tests: Add tests for awaitable return of async routines

 tests/test_async.py | 201 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 201 insertions(+)
---
diff --git a/tests/test_async.py b/tests/test_async.py
new file mode 100644
index 00000000..ac3629c7
--- /dev/null
+++ b/tests/test_async.py
@@ -0,0 +1,201 @@
+# -*- Mode: Python; py-indent-offset: 4 -*-
+# vim: tabstop=4 shiftwidth=4 expandtab
+
+import sys
+import unittest
+import pytest
+
+import asyncio
+from gi.repository import GLib, Gio
+if sys.platform != 'win32':
+    from gi.events import GLibEventLoopPolicy
+
+
+class TestAsync(unittest.TestCase):
+
+    def setUp(self):
+        if sys.platform == 'win32':
+            raise unittest.SkipTest("Not supported on Windows")
+
+        policy = GLibEventLoopPolicy()
+        asyncio.set_event_loop_policy(policy)
+        self.addCleanup(asyncio.set_event_loop_policy, None)
+        self.loop = policy.get_event_loop()
+        self.addCleanup(self.loop.close)
+
+    def test_async_enumerate(self):
+        f = Gio.file_new_for_path("./")
+
+        called = False
+
+        def cb():
+            nonlocal called
+            called = True
+
+        async def run():
+            nonlocal called, self
+
+            self.loop.call_soon(cb)
+
+            iter_info = []
+            for info in await f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT):
+                iter_info.append(info.get_name())
+
+            # The await runs the mainloop and cb is called.
+            self.assertEqual(called, True)
+
+            next_info = []
+            enumerator = f.enumerate_children("standard::*", 0, None)
+            while True:
+                info = enumerator.next_file(None)
+                if info is None:
+                    break
+                next_info.append(info.get_name())
+
+            self.assertEqual(iter_info, next_info)
+
+        self.loop.run_until_complete(run())
+
+    def test_async_cancellation(self):
+        """Cancellation raises G_IO_ERROR_CANCELLED"""
+
+        f = Gio.file_new_for_path("./")
+
+        async def run():
+            nonlocal self
+
+            # cancellable created implicitly
+            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
+            res.cancel()
+            with self.assertRaisesRegex(GLib.GError, "Operation was cancelled"):
+                await res
+
+            # cancellable passed explicitly
+            cancel = Gio.Cancellable()
+            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT, cancel)
+            self.assertEqual(res.cancellable, cancel)
+            cancel.cancel()
+            with self.assertRaisesRegex(GLib.GError, "Operation was cancelled"):
+                await res
+
+        self.loop.run_until_complete(run())
+
+    def test_not_completed(self):
+        """Querying an uncompleted task raises exceptions"""
+
+        f = Gio.file_new_for_path("./")
+
+        async def run():
+            nonlocal self
+
+            # cancellable created implicitly
+            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
+            with self.assertRaises(asyncio.InvalidStateError):
+                res.result()
+
+            with self.assertRaises(asyncio.InvalidStateError):
+                res.exception()
+
+            # And, await it
+            await res
+
+        self.loop.run_until_complete(run())
+
+    def test_async_cancel_completed(self):
+        """Cancelling a completed task just cancels the cancellable"""
+
+        f = Gio.file_new_for_path("./")
+
+        async def run():
+            nonlocal self
+
+            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
+            await res
+            assert not res.cancellable.is_cancelled()
+            res.cancel()
+            assert res.cancellable.is_cancelled()
+
+        self.loop.run_until_complete(run())
+
+    def test_async_completed_add_cb(self):
+        """Adding a done cb to a completed future queues it with call_soon"""
+
+        f = Gio.file_new_for_path("./")
+
+        called = False
+
+        def cb():
+            nonlocal called
+            called = True
+
+        async def run():
+            nonlocal called, self
+
+            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
+            await res
+            self.loop.call_soon(cb)
+
+            # Python await is smart and does not iterate the EventLoop
+            await res
+            assert not called
+
+            # So create a new future and wait on that
+            fut = asyncio.Future()
+
+            def done_cb(res):
+                nonlocal fut
+                fut.set_result(res.result())
+
+            res.add_done_callback(done_cb)
+            await fut
+            assert called
+
+        self.loop.run_until_complete(run())
+
+    def test_deleting_failed_logs(self):
+        f = Gio.file_new_for_path("./")
+
+        async def run():
+            nonlocal self
+
+            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
+            res.cancel()
+            # Cancellation in Gio is not immediate, so sleep for a bit
+            await asyncio.sleep(0.5)
+
+        exc = None
+        msg = None
+
+        def handler(loop, context):
+            nonlocal exc, msg
+            msg = context['message']
+            exc = context['exception']
+
+        self.loop.set_exception_handler(handler)
+        self.loop.run_until_complete(run())
+
+        self.assertRegex(msg, ".*exception was never retrieved")
+        self.assertIsInstance(exc, GLib.GError)
+
+    @pytest.mark.xfail(reason="BEHAVIOUR: Async routines need a running EventLoop for the current 
GMainContext")
+    def test_no_running_loop(self):
+        f = Gio.file_new_for_path("./")
+
+        res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
+        self.assertEqual(res._loop, self.loop)
+
+    @pytest.mark.xfail(reason="BEHAVIOUR: Async routines need a running EventLoop for the current 
GMainContext")
+    def test_wrong_default_context(self):
+        f = Gio.file_new_for_path("./")
+
+        async def run():
+            nonlocal self
+
+            ctx = GLib.MainContext.new()
+            GLib.MainContext.push_thread_default(ctx)
+            self.addCleanup(GLib.MainContext.pop_thread_default, ctx)
+
+            with self.assertRaises(RuntimeError):
+                await f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
+
+        self.loop.run_until_complete(run())