add Response.max_cookie_size config

tests/test_basic.py

@@ -1917,3 +1917,33 @@ def test_run_from_config(monkeypatch, host, port, expect_host, expect_port, app)
     monkeypatch.setattr(werkzeug.serving, 'run_simple', run_simple_mock)
     app.config['SERVER_NAME'] = 'pocoo.org:8080'
     app.run(host, port)
+
+
+def test_max_cookie_size(app, client, recwarn):
+    app.config['MAX_COOKIE_SIZE'] = 100
+
+    # outside app context, default to Werkzeug static value,
+    # which is also the default config
+    response = flask.Response()
+    default = flask.Flask.default_config['MAX_COOKIE_SIZE']
+    assert response.max_cookie_size == default
+
+    # inside app context, use app config
+    with app.app_context():
+        assert flask.Response().max_cookie_size == 100
+
+    @app.route('/')
+    def index():
+        r = flask.Response('', status=204)
+        r.set_cookie('foo', 'bar' * 100)
+        return r
+
+    client.get('/')
+    assert len(recwarn) == 1
+    w = recwarn.pop()
+    assert 'cookie is too large' in str(w.message)
+
+    app.config['MAX_COOKIE_SIZE'] = 0
+
+    client.get('/')
+    assert len(recwarn) == 0