Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
factory_boy: testing like a pro. DjangoCon EU 2022
Search
Camila Maia
September 22, 2022
Technology
1
710
factory_boy: testing like a pro. DjangoCon EU 2022
https://pretalx.evolutio.pt/djangocon-europe-2022/talk/XWUYA8/
Camila Maia
September 22, 2022
Tweet
Share
More Decks by Camila Maia
See All by Camila Maia
GitHub Actions - Semana DevOps LINUXTips.pdf
camilamaia
0
32
Minha Jornada em Developer Experience (DX) - DevOpsDays Salvador 2024
camilamaia
0
28
Cumbuca Dev: Ensinando com Open Source - 71º Python Floripa no MeLi
camilamaia
0
60
COMO E PORQUE ENSINAR A PROGRAMAR COM OPEN SOURCE - Python Brasil 2023
camilamaia
0
46
Como testar e manter APIs de qualidade - Codecon Digital 2023
camilamaia
0
1k
factory_boy: testing like a pro. DjangoCon US 2022
camilamaia
0
680
ScanAPI Workshop. DjangoCon EU 2022
camilamaia
0
620
Como testar e documentar REST APIs com ScanAPI - Agile Testers Conference 2021
camilamaia
0
310
factory_boy: Testando Objetos Complexos Python Brasil 2021
camilamaia
0
420
Other Decks in Technology
See All in Technology
ウォンテッドリーのアラート設計と Datadog 移行での知見
donkomura
0
170
Amazon Inspector コードセキュリティで手軽に実現するシフトレフト
maimyyym
0
150
o11yツールを乗り換えた話
tak0x00
2
1.7k
JAWS-UG のイベントで使うハンズオンシナリオを Amazon Q Developer for CLI で作ってみた話
kazzpapa3
0
120
はじめての転職講座/The Guide of First Career Change
kwappa
5
4.4k
データモデリング通り #2オンライン勉強会 ~方法論の話をしよう~
datayokocho
0
190
Oracle Base Database Service:サービス概要のご紹介
oracle4engineer
PRO
1
20k
MCPサーバーを活用したAWSコスト管理
arie0703
0
130
文字列の並び順 / String Collation
tmtms
1
110
GCASアップデート(202506-202508)
techniczna
0
210
形式手法特論:位相空間としての並行プログラミング #kernelvm / Kernel VM Study Tokyo 18th
ytaka23
3
1.5k
信頼できる開発プラットフォームをどう作るか?-Governance as Codeと継続的監視/フィードバックが導くPlatform Engineeringの進め方
yuriemori
1
210
Featured
See All Featured
What’s in a name? Adding method to the madness
productmarketing
PRO
23
3.6k
XXLCSS - How to scale CSS and keep your sanity
sugarenia
248
1.3M
We Have a Design System, Now What?
morganepeng
53
7.7k
The Power of CSS Pseudo Elements
geoffreycrofte
77
5.9k
Rails Girls Zürich Keynote
gr2m
95
14k
Practical Tips for Bootstrapping Information Extraction Pipelines
honnibal
PRO
23
1.4k
Building an army of robots
kneath
306
45k
Optimising Largest Contentful Paint
csswizardry
37
3.4k
Building a Scalable Design System with Sketch
lauravandoore
462
33k
Making Projects Easy
brettharned
117
6.3k
BBQ
matthewcrist
89
9.8k
[Rails World 2023 - Day 1 Closing Keynote] - The Magic of Rails
eileencodes
36
2.5k
Transcript
@cmaiacd factory_boy DjangoCon EU 2022 - Porto Camila Maia
testing like a pro
@cmaiacd You can find this presentation at: speakerdeck.com/cmaiacd
@cmaiacd Who am I?
@cmaiacd Backend Developer @
@cmaiacd Brazilian
@cmaiacd Living in Berlin
@cmaiacd Queer
@cmaiacd 🐶
@cmaiacd Coding since 2010 👵
@cmaiacd Python 🐍 and Ruby 💎
@cmaiacd Community ❤
@cmaiacd Conferences
@cmaiacd Open Source ❤
@cmaiacd Creator of ScanAPI
@cmaiacd +1.5k + 1.2k ⭐
@cmaiacd Workshop Tomorrow 4:55 PM
@cmaiacd
@cmaiacd factory_boy: what is it?
@cmaiacd It is a fixtures replacement
@cmaiacd Based on factory_bot (Thoughtbot)
@cmaiacd First version: Django only Nowadays: framework-independent Unittest, Pytest...
@cmaiacd For complex objects: ❌ Fixtures: static, hard to maintain
✅ Factories: easy-to-use
@cmaiacd
@cmaiacd 🧰 🛠 🔧 ⚙ Sequence Faker Fuzzy attributes LazyFunction
LazyAttribute Inheritance Inheritance Params Traits Strategies RelatedFactory / SubFactory
@cmaiacd My Experience
@cmaiacd +3 years Django Monolith 🐘
@cmaiacd +230 tables +2200 relevant files +75k relevant lines
@cmaiacd
@cmaiacd A poorly designed factory might affect many tests
@cmaiacd Implicit errors
@cmaiacd The tests are created in a way to fit
the factory factory-oriented testing
@cmaiacd Factories can get too tied
@cmaiacd Developers bump into the same issue again and again
@cmaiacd Patterns 👀 Best practices? 🤔
@cmaiacd Demo App
@cmaiacd Polls
@cmaiacd Poll
@cmaiacd Results
@cmaiacd s
@cmaiacd Model - Poll Poll Question Choice n:1 pub_date :
DateTimeField premium : BooleanField author : CharField question_text : CharField language : CharField choice_text : CharField votes : IntegerField 1:1
@cmaiacd Model - Poll
@cmaiacd Model - Poll
@cmaiacd Model - Question
@cmaiacd Model - Choice
@cmaiacd Best Practices
@cmaiacd 1. FACTORIES SHOULD REPRESENT THEIR MODELS
@cmaiacd Avoid implicit errors
@cmaiacd BAD ❌
@cmaiacd GOOD ✅
@cmaiacd 2. DO NOT RELY ON DEFAULTS FROM FACTORIES
@cmaiacd • If a default value is changed, all tests
that depend on it will break • The setup of a test should contain all the logic to ensure it will always pass • Explicit better than implicit
@cmaiacd BAD ❌
@cmaiacd GOOD ✅
@cmaiacd 3. FACTORIES SHOULD CONTAIN ONLY THE REQUIRED DATA
@cmaiacd If the field is nullable (null=True) the attribute should
be under a trait and not as a default value
@cmaiacd BAD ❌
@cmaiacd GOOD ✅
@cmaiacd If we want to have an author, we can
use PollFactory(with_author=True) now When are we going to remember to test the case PollFactory(author=None)? We should not assume there is an author when DB actually allows to not have it.
@cmaiacd 4. BUILD OVER CREATE
@cmaiacd MyFactory.build() creates a local object (memory) MyFactory.create() creates a
local object + stores it in the DB
@cmaiacd BAD ❌
@cmaiacd GOOD ✅
@cmaiacd BUILD STRATEGY ========== 14 passed in 1.76 seconds ==========
CREATE STRATEGY ========== 14 passed in 3.26 seconds ==========
@cmaiacd 5. IF FK IS IN THE TABLE: SUBFACTOR IF
FK IS IN THE OTHER TABLE: RELATEDFACTORY + TRAIT
@cmaiacd SubFactory: builds/creates the SubFactory during the process of creation
of the main factory RelatedFactory: builds/creates the RelatedFactory after creating the main factory
@cmaiacd Good ✅
@cmaiacd 6. USE FIXTURES TO WRAP FACTORIES TO AVOID DUPLICATION
@cmaiacd BAD ❌
@cmaiacd GOOD ✅
@cmaiacd 7. AVOID SHARING FACTORIES OR FIXTURES AMONG DIFFERENT FILES
@cmaiacd Many tests depending on the same factory/fixture
@cmaiacd Tends to inflate the factory/fixture
@cmaiacd Hard to maintain
@cmaiacd Change a factory/fixture… tons of tests breaking
@cmaiacd Fixture / Factory oriented testing
@cmaiacd Ok, ok, I got it! 😌 Now I know
the best practices 💪
@cmaiacd So let’s try to fix one first factory… 🤓
@cmaiacd
@cmaiacd Baby steps 🐣
@cmaiacd Código
@cmaiacd Official doc 📄 factoryboy.readthedocs.io
@cmaiacd Common recipes factoryboy.readthedocs.io/ en/stable/recipes.html
@cmaiacd Code github.com/FactoryBoy/ factory_boy
@cmaiacd THANK YOU! MUITO OBRIGADA! @cmaiacd camilamaia cmaiacd.com