add config and docs for limits

tests/test_basic.py

@@ -1538,27 +1538,6 @@ def test_werkzeug_passthrough_errors(
     app.run(debug=debug, use_debugger=use_debugger, use_reloader=use_reloader)
 
 
-def test_max_content_length(app, client):
-    app.config["MAX_CONTENT_LENGTH"] = 64
-
-    @app.before_request
-    def always_first():
-        flask.request.form["myfile"]
-        AssertionError()
-
-    @app.route("/accept", methods=["POST"])
-    def accept_file():
-        flask.request.form["myfile"]
-        AssertionError()
-
-    @app.errorhandler(413)
-    def catcher(error):
-        return "42"
-
-    rv = client.post("/accept", data={"myfile": "foo" * 100})
-    assert rv.data == b"42"
-
-
 def test_url_processors(app, client):
     @app.url_defaults
     def add_language_code(endpoint, values):