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
Maintainable Integration Testing in React
Search
Matija Marohnić
February 22, 2018
Programming
0
31
Maintainable Integration Testing in React
Matija Marohnić
February 22, 2018
Tweet
Share
More Decks by Matija Marohnić
See All by Matija Marohnić
Introduction to Remix
silvenon
0
140
Cypress vs. Playwright
silvenon
0
160
Studying Strapi: an open source head headless CMS
silvenon
0
38
CSS Specificity
silvenon
0
30
Make your JavaScript projects more accessible to newcomers
silvenon
0
73
React Hooks
silvenon
0
72
PostCSS
silvenon
0
43
CSS Custom Properties
silvenon
0
40
Writing Codemods with jscodeshift
silvenon
0
29
Other Decks in Programming
See All in Programming
意外と簡単!?フロントエンドでパスキー認証を実現する WebAuthn
teamlab
PRO
2
760
Introducing ReActionView: A new ActionView-compatible ERB Engine @ Rails World 2025, Amsterdam
marcoroth
0
690
Amazon RDS 向けに提供されている MCP Server と仕組みを調べてみた/jawsug-okayama-2025-aurora-mcp
takahashiikki
1
110
Compose Multiplatform × AI で作る、次世代アプリ開発支援ツールの設計と実装
thagikura
0
160
🔨 小さなビルドシステムを作る
momeemt
4
680
AI Coding Agentのセキュリティリスク:PRの自己承認とメルカリの対策
s3h
0
230
JSONataを使ってみよう Step Functionsが楽しくなる実践テクニック #devio2025
dafujii
1
530
Rancher と Terraform
fufuhu
2
550
Swift Updates - Learn Languages 2025
koher
2
480
Cache Me If You Can
ryunen344
2
1.5k
go test -json そして testing.T.Attr / Kyoto.go #63
utgwkk
3
310
Tool Catalog Agent for Bedrock AgentCore Gateway
licux
6
2.5k
Featured
See All Featured
Visualization
eitanlees
148
16k
GraphQLとの向き合い方2022年版
quramy
49
14k
BBQ
matthewcrist
89
9.8k
VelocityConf: Rendering Performance Case Studies
addyosmani
332
24k
Building Flexible Design Systems
yeseniaperezcruz
328
39k
The Art of Delivering Value - GDevCon NA Keynote
reverentgeek
15
1.7k
How to train your dragon (web standard)
notwaldorf
96
6.2k
Being A Developer After 40
akosma
90
590k
Exploring the Power of Turbo Streams & Action Cable | RailsConf2023
kevinliebholz
34
6k
Code Review Best Practice
trishagee
70
19k
Fantastic passwords and where to find them - at NoRuKo
philnash
52
3.4k
Sharpening the Axe: The Primacy of Toolmaking
bcantrill
44
2.5k
Transcript
None
Matija Marohnić @silvenon
Maintainable Integration Testing in React
Integration testing Unit testing End-to-end testing
Unit testing Are isolated parts of this feature working?
Integration testing Is this feature supposed to work?
End-to-end testing Does this feature actually work in a real
browser?
$$$ ¢ E2E Integration Unit Testing pyramid
•flaky/brittle •“too much of a hassle” •some features are hard
to test Case against frontend testing
•flaky → pass and fail with the same code •brittle
→ easily broken Flaky/brittle
•an afterthought, something to “deal with later” •not considered an
essential part of development “Too much of a hassle”
•e.g. some advanced APIs •async doesn’t help, it’s often about
timing •developers skip challenging tests, but never return Some features are hard to test
None
•integration tests focus on features •unit tests focus on implementation
details Why “mostly integration”?
How do you feel after writing a test?
None
–Me “A test is useless if you’re equally likely to
make a mistake in the implementation and the test itself.”
•usually developers strive towards 100% •important in libraries and APIs
•not really in frontend application code Test coverage
“You should write tests”
Testing in React
•simulating events •traversing through the tree •mounting in the DOM
or shallow rendering React test utilities
Mounting
Shallow rendering
Shallow vs. mount Unit vs. integration
•a complete testing framework •built-in jsdom •powerful assertions •easy mocking
Jest
•Enzyme •built on top of React’s test utilities •useful high-level
API •Nock •imitates a server Companion tools
Example: DataGrid
None
•opening a DataGrid displays features of the currently selected layer
Testing features Do Don’t •opening a DataGrid makes a certain API request
None
•creating a filter causes features to reduce to an expected
set Testing features Do Don’t •creating a filter displays a chip component
What about the API?
Nock
Nock
•battle-testing some modules in a cheap way •a disposable crutch
during development So when to unit test?
None
If the whole thing works together, chances are that its
parts are working as well