EuroPython 2022 - Dance with shadows: stubs, patch and mock - presented by María Andrea Vignau [Liffey Hall 2 on 2022-07-13] A comprehensive but simple introduction to the use of fake objects. Explain how to inject this object and use in test using patch and the awesome and powerful mock objects . Last, I present some very interesting specialized libraries for mocking on web development. Outline 0:00 I present the key factors to use fake objects, and present some dangers. 3:00 Discuss some wanted characteristics in this kind of components. 6:00 Patching: how to do that and some common mistakes. After that I present patch scopes and some disadvantage in the use of this technique. 10:00 Inverse dependency as an possible alternative to patch 13:00 Mocks properties: return value, side effect and specs. Using mocks as spy functions or wrappers. Asserting on callings. 21:00 Using special libraries for mocking. Presenting pyvcr and moto." This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License http://creativecommons.org/licenses/by-nc-sa/4.0/