Change Payload Too Large process

When Payload Too Large occurs, it uses error handler.

tests/test_payload_too_large.py

@@ -0,0 +1,54 @@
+from sanic import Sanic
+from sanic.response import text
+from sanic.exceptions import PayloadTooLarge
+from sanic.utils import sanic_endpoint_test
+
+data_received_app = Sanic('data_received')
+data_received_app.config.REQUEST_MAX_SIZE = 1
+data_received_default_app = Sanic('data_received_default')
+data_received_default_app.config.REQUEST_MAX_SIZE = 1
+on_header_default_app = Sanic('on_header')
+on_header_default_app.config.REQUEST_MAX_SIZE = 500
+
+
+@data_received_app.route('/1')
+async def handler1(request):
+    return text('OK')
+
+
+@data_received_app.exception(PayloadTooLarge)
+def handler_exception(request, exception):
+    return text('Payload Too Large from error_handler.', 413)
+
+
+def test_payload_too_large_from_error_handler():
+    response = sanic_endpoint_test(
+        data_received_app, uri='/1', gather_request=False)
+    assert response.status == 413
+    assert response.text == 'Payload Too Large from error_handler.'
+
+
+@data_received_default_app.route('/1')
+async def handler2(request):
+    return text('OK')
+
+
+def test_payload_too_large_at_data_received_default():
+    response = sanic_endpoint_test(
+        data_received_default_app, uri='/1', gather_request=False)
+    assert response.status == 413
+    assert response.text == 'Error: Payload Too Large'
+
+
+@on_header_default_app.route('/1')
+async def handler3(request):
+    return text('OK')
+
+
+def test_payload_too_large_at_on_header_default():
+    data = 'a' * 1000
+    response = sanic_endpoint_test(
+        on_header_default_app, method='post', uri='/1',
+        gather_request=False, data=data)
+    assert response.status == 413
+    assert response.text == 'Error: Payload Too Large'