add a flag to skip SIGINT and SIGTERM signals registration

tests/test_sanic.py

@@ -0,0 +1,41 @@
+from sanic import Sanic
+from sanic.response import HTTPResponse
+from sanic.utils import HOST, PORT
+from unittest.mock import MagicMock
+import pytest
+import asyncio
+
+
+async def stop(app):
+    await asyncio.sleep(0.2)
+    app.stop()
+
+
+def test_register_system_signals():
+    """Test if sanic register system signals"""
+    app = Sanic('test_register_system_signals')
+
+    @app.route('/hello')
+    async def hello_route(request):
+        return HTTPResponse()
+
+    loop = asyncio.new_event_loop()
+    loop.add_signal_handler = MagicMock()
+    asyncio.ensure_future(stop(app), loop=loop)
+    app.run(HOST, PORT, loop=loop)
+    assert loop.add_signal_handler.called == True
+
+
+def test_dont_register_system_signals():
+    """Test if sanic don't register system signals"""
+    app = Sanic('test_register_system_signals')
+
+    @app.route('/hello')
+    async def hello_route(request):
+        return HTTPResponse()
+
+    loop = asyncio.new_event_loop()
+    loop.add_signal_handler = MagicMock()
+    asyncio.ensure_future(stop(app), loop=loop)
+    app.run(HOST, PORT, loop=loop, register_sys_signals=False)
+    assert loop.add_signal_handler.called == False