gh-108388: Convert test_concurrent_futures to package (#108401)

Convert test_concurrent_futures to a package of sub-tests.

1 files changed, 291 insertions, 0 deletions

diff --git a/Lib/test/test_concurrent_futures/test_future.py b/Lib/test/test_concurrent_futures/test_future.py
new file mode 100644
index 00000000000..4066ea1ee4b
--- /dev/null
+++ b/Lib/test/test_concurrent_futures/test_future.py
@@ -0,0 +1,291 @@
+import threading
+import time
+import unittest
+from concurrent import futures
+from concurrent.futures._base import (
+    PENDING, RUNNING, CANCELLED, CANCELLED_AND_NOTIFIED, FINISHED, Future)
+
+from test import support
+
+from .util import (
+    PENDING_FUTURE, RUNNING_FUTURE, CANCELLED_FUTURE,
+    CANCELLED_AND_NOTIFIED_FUTURE, EXCEPTION_FUTURE, SUCCESSFUL_FUTURE,
+    BaseTestCase, create_future, setup_module)
+
+
+class FutureTests(BaseTestCase):
+    def test_done_callback_with_result(self):
+        callback_result = None
+        def fn(callback_future):
+            nonlocal callback_result
+            callback_result = callback_future.result()
+
+        f = Future()
+        f.add_done_callback(fn)
+        f.set_result(5)
+        self.assertEqual(5, callback_result)
+
+    def test_done_callback_with_exception(self):
+        callback_exception = None
+        def fn(callback_future):
+            nonlocal callback_exception
+            callback_exception = callback_future.exception()
+
+        f = Future()
+        f.add_done_callback(fn)
+        f.set_exception(Exception('test'))
+        self.assertEqual(('test',), callback_exception.args)
+
+    def test_done_callback_with_cancel(self):
+        was_cancelled = None
+        def fn(callback_future):
+            nonlocal was_cancelled
+            was_cancelled = callback_future.cancelled()
+
+        f = Future()
+        f.add_done_callback(fn)
+        self.assertTrue(f.cancel())
+        self.assertTrue(was_cancelled)
+
+    def test_done_callback_raises(self):
+        with support.captured_stderr() as stderr:
+            raising_was_called = False
+            fn_was_called = False
+
+            def raising_fn(callback_future):
+                nonlocal raising_was_called
+                raising_was_called = True
+                raise Exception('doh!')
+
+            def fn(callback_future):
+                nonlocal fn_was_called
+                fn_was_called = True
+
+            f = Future()
+            f.add_done_callback(raising_fn)
+            f.add_done_callback(fn)
+            f.set_result(5)
+            self.assertTrue(raising_was_called)
+            self.assertTrue(fn_was_called)
+            self.assertIn('Exception: doh!', stderr.getvalue())
+
+    def test_done_callback_already_successful(self):
+        callback_result = None
+        def fn(callback_future):
+            nonlocal callback_result
+            callback_result = callback_future.result()
+
+        f = Future()
+        f.set_result(5)
+        f.add_done_callback(fn)
+        self.assertEqual(5, callback_result)
+
+    def test_done_callback_already_failed(self):
+        callback_exception = None
+        def fn(callback_future):
+            nonlocal callback_exception
+            callback_exception = callback_future.exception()
+
+        f = Future()
+        f.set_exception(Exception('test'))
+        f.add_done_callback(fn)
+        self.assertEqual(('test',), callback_exception.args)
+
+    def test_done_callback_already_cancelled(self):
+        was_cancelled = None
+        def fn(callback_future):
+            nonlocal was_cancelled
+            was_cancelled = callback_future.cancelled()
+
+        f = Future()
+        self.assertTrue(f.cancel())
+        f.add_done_callback(fn)
+        self.assertTrue(was_cancelled)
+
+    def test_done_callback_raises_already_succeeded(self):
+        with support.captured_stderr() as stderr:
+            def raising_fn(callback_future):
+                raise Exception('doh!')
+
+            f = Future()
+
+            # Set the result first to simulate a future that runs instantly,
+            # effectively allowing the callback to be run immediately.
+            f.set_result(5)
+            f.add_done_callback(raising_fn)
+
+            self.assertIn('exception calling callback for', stderr.getvalue())
+            self.assertIn('doh!', stderr.getvalue())
+
+
+    def test_repr(self):
+        self.assertRegex(repr(PENDING_FUTURE),
+                         '<Future at 0x[0-9a-f]+ state=pending>')
+        self.assertRegex(repr(RUNNING_FUTURE),
+                         '<Future at 0x[0-9a-f]+ state=running>')
+        self.assertRegex(repr(CANCELLED_FUTURE),
+                         '<Future at 0x[0-9a-f]+ state=cancelled>')
+        self.assertRegex(repr(CANCELLED_AND_NOTIFIED_FUTURE),
+                         '<Future at 0x[0-9a-f]+ state=cancelled>')
+        self.assertRegex(
+                repr(EXCEPTION_FUTURE),
+                '<Future at 0x[0-9a-f]+ state=finished raised OSError>')
+        self.assertRegex(
+                repr(SUCCESSFUL_FUTURE),
+                '<Future at 0x[0-9a-f]+ state=finished returned int>')
+
+    def test_cancel(self):
+        f1 = create_future(state=PENDING)
+        f2 = create_future(state=RUNNING)
+        f3 = create_future(state=CANCELLED)
+        f4 = create_future(state=CANCELLED_AND_NOTIFIED)
+        f5 = create_future(state=FINISHED, exception=OSError())
+        f6 = create_future(state=FINISHED, result=5)
+
+        self.assertTrue(f1.cancel())
+        self.assertEqual(f1._state, CANCELLED)
+
+        self.assertFalse(f2.cancel())
+        self.assertEqual(f2._state, RUNNING)
+
+        self.assertTrue(f3.cancel())
+        self.assertEqual(f3._state, CANCELLED)
+
+        self.assertTrue(f4.cancel())
+        self.assertEqual(f4._state, CANCELLED_AND_NOTIFIED)
+
+        self.assertFalse(f5.cancel())
+        self.assertEqual(f5._state, FINISHED)
+
+        self.assertFalse(f6.cancel())
+        self.assertEqual(f6._state, FINISHED)
+
+    def test_cancelled(self):
+        self.assertFalse(PENDING_FUTURE.cancelled())
+        self.assertFalse(RUNNING_FUTURE.cancelled())
+        self.assertTrue(CANCELLED_FUTURE.cancelled())
+        self.assertTrue(CANCELLED_AND_NOTIFIED_FUTURE.cancelled())
+        self.assertFalse(EXCEPTION_FUTURE.cancelled())
+        self.assertFalse(SUCCESSFUL_FUTURE.cancelled())
+
+    def test_done(self):
+        self.assertFalse(PENDING_FUTURE.done())
+        self.assertFalse(RUNNING_FUTURE.done())
+        self.assertTrue(CANCELLED_FUTURE.done())
+        self.assertTrue(CANCELLED_AND_NOTIFIED_FUTURE.done())
+        self.assertTrue(EXCEPTION_FUTURE.done())
+        self.assertTrue(SUCCESSFUL_FUTURE.done())
+
+    def test_running(self):
+        self.assertFalse(PENDING_FUTURE.running())
+        self.assertTrue(RUNNING_FUTURE.running())
+        self.assertFalse(CANCELLED_FUTURE.running())
+        self.assertFalse(CANCELLED_AND_NOTIFIED_FUTURE.running())
+        self.assertFalse(EXCEPTION_FUTURE.running())
+        self.assertFalse(SUCCESSFUL_FUTURE.running())
+
+    def test_result_with_timeout(self):
+        self.assertRaises(futures.TimeoutError,
+                          PENDING_FUTURE.result, timeout=0)
+        self.assertRaises(futures.TimeoutError,
+                          RUNNING_FUTURE.result, timeout=0)
+        self.assertRaises(futures.CancelledError,
+                          CANCELLED_FUTURE.result, timeout=0)
+        self.assertRaises(futures.CancelledError,
+                          CANCELLED_AND_NOTIFIED_FUTURE.result, timeout=0)
+        self.assertRaises(OSError, EXCEPTION_FUTURE.result, timeout=0)
+        self.assertEqual(SUCCESSFUL_FUTURE.result(timeout=0), 42)
+
+    def test_result_with_success(self):
+        # TODO(brian@sweetapp.com): This test is timing dependent.
+        def notification():
+            # Wait until the main thread is waiting for the result.
+            time.sleep(1)
+            f1.set_result(42)
+
+        f1 = create_future(state=PENDING)
+        t = threading.Thread(target=notification)
+        t.start()
+
+        self.assertEqual(f1.result(timeout=5), 42)
+        t.join()
+
+    def test_result_with_cancel(self):
+        # TODO(brian@sweetapp.com): This test is timing dependent.
+        def notification():
+            # Wait until the main thread is waiting for the result.
+            time.sleep(1)
+            f1.cancel()
+
+        f1 = create_future(state=PENDING)
+        t = threading.Thread(target=notification)
+        t.start()
+
+        self.assertRaises(futures.CancelledError,
+                          f1.result, timeout=support.SHORT_TIMEOUT)
+        t.join()
+
+    def test_exception_with_timeout(self):
+        self.assertRaises(futures.TimeoutError,
+                          PENDING_FUTURE.exception, timeout=0)
+        self.assertRaises(futures.TimeoutError,
+                          RUNNING_FUTURE.exception, timeout=0)
+        self.assertRaises(futures.CancelledError,
+                          CANCELLED_FUTURE.exception, timeout=0)
+        self.assertRaises(futures.CancelledError,
+                          CANCELLED_AND_NOTIFIED_FUTURE.exception, timeout=0)
+        self.assertTrue(isinstance(EXCEPTION_FUTURE.exception(timeout=0),
+                                   OSError))
+        self.assertEqual(SUCCESSFUL_FUTURE.exception(timeout=0), None)
+
+    def test_exception_with_success(self):
+        def notification():
+            # Wait until the main thread is waiting for the exception.
+            time.sleep(1)
+            with f1._condition:
+                f1._state = FINISHED
+                f1._exception = OSError()
+                f1._condition.notify_all()
+
+        f1 = create_future(state=PENDING)
+        t = threading.Thread(target=notification)
+        t.start()
+
+        self.assertTrue(isinstance(f1.exception(timeout=support.SHORT_TIMEOUT), OSError))
+        t.join()
+
+    def test_multiple_set_result(self):
+        f = create_future(state=PENDING)
+        f.set_result(1)
+
+        with self.assertRaisesRegex(
+                futures.InvalidStateError,
+                'FINISHED: <Future at 0x[0-9a-f]+ '
+                'state=finished returned int>'
+        ):
+            f.set_result(2)
+
+        self.assertTrue(f.done())
+        self.assertEqual(f.result(), 1)
+
+    def test_multiple_set_exception(self):
+        f = create_future(state=PENDING)
+        e = ValueError()
+        f.set_exception(e)
+
+        with self.assertRaisesRegex(
+                futures.InvalidStateError,
+                'FINISHED: <Future at 0x[0-9a-f]+ '
+                'state=finished raised ValueError>'
+        ):
+            f.set_exception(Exception())
+
+        self.assertEqual(f.exception(), e)
+
+
+def setUpModule():
+    setup_module()
+
+
+if __name__ == "__main__":
+    unittest.main()