Fix Ctrl+C and tests on Windows. (#1808)

* Fix Ctrl+C on Windows.

* Disable testing of a function N/A on Windows.

* Add test for coverage, avoid crash on missing _stopping.

* Initialise StreamingHTTPResponse.protocol = None

* Improved comments.

* Reduce amount of data in test_request_stream to avoid failures on Windows.

* The Windows test doesn't work on Windows :(

* Use port numbers more likely to be free than 8000.

* Disable the other signal tests on Windows as well.

* Windows doesn't properly support SO_REUSEADDR, so that's disabled in Python, and thus rebinding fails. For successful testing, reuse port instead.

* app.run argument handling: added server kwargs (alike create_server), added warning on extra kwargs, made auto_reload explicit argument. Another go at Windows tests

* Revert "app.run argument handling: added server kwargs (alike create_server), added warning on extra kwargs, made auto_reload explicit argument. Another go at Windows tests"

This reverts commit dc5d682448.

* Use random test server port on most tests. Should avoid port/addr reuse issues.

* Another test to random port instead of 8000.

* Fix deprecation warnings about missing name on Sanic() in tests.

* Linter and typing

* Increase test coverage

* Rewrite test for ctrlc_windows_workaround

* py36 compat

* py36 compat

* py36 compat

* Don't rely on loop internals but add a stopping flag to app.

* App may be restarted.

* py36 compat

* Linter

* Add a constant for OS checking.

Co-authored-by: L. Kärkkäinen <tronic@users.noreply.github.com>

sanic/app.py

@@ -81,6 +81,7 @@ class Sanic:
         self.sock = None
         self.strict_slashes = strict_slashes
         self.listeners = defaultdict(list)
+        self.is_stopping = False
         self.is_running = False
         self.is_request_stream = False
         self.websocket_enabled = False
@@ -1177,6 +1178,7 @@ class Sanic:
 
         try:
             self.is_running = True
+            self.is_stopping = False
             if workers > 1 and os.name != "posix":
                 logger.warn(
                     f"Multiprocessing is currently not supported on {os.name},"
@@ -1209,7 +1211,9 @@ class Sanic:
 
     def stop(self):
         """This kills the Sanic"""
-        get_event_loop().stop()
+        if not self.is_stopping:
+            self.is_stopping = True
+            get_event_loop().stop()
 
     async def create_server(
         self,