2.4 KiB
2.4 KiB
Unit Testing Framework
- Status: Accepted
- Supersedes ES-compatible unit test frameworks (ADR#0000)
- Deciders: Monitor team
- Date: 2023-07-25
Technical Story: MNTOR-1823
Context and Problem Statement
With the transition to Next.js/React, the team wants to consider testing frameworks again, to confirm what works best for the new architecture.
Decision Drivers
- What works best for the current framework, Next.js
- Which provides the best experience for developers
Considered Options
- No Change - Ava (ES6+ compatible test runner)
- Jest (with the Rust Compiler)
- Jest (with Babel)
Decision Outcome
Jest (with the Rust Compiler)
This decision was made in an effort to go with what has the most support for our framework (Nextjs).
Positive Consequences
- Easy to port past tests (Already completed in #3168)
- Compability with Nextjs framework
Negative Consequences
- Still doesn't fully support ES6+ modules
Pros and Cons of the Options
No Change - Ava (ES6+ compatible test runner)
- Good, because the system under test and the test code are pure ES modules
- Good, because the system under test needs no changes
- Bad, because the unit tests need to be rewritten to use the new non-jest test runner and mocking library
Jest (with the Rust Compiler)
Use Jest and the default compiler, SWC
- Good, Next.js now has built-in configuration for Jest
- Good, Auto mocks of
.css,.module.css(and their.scssvariants), and image imports - Good, Automatically sets up
transformusing SWC - Good, Loads
.env(and all variants) into process.env - Good, Ignores
node_modulesfrom test resolving and transforms - Good, Ignores
.nextfrom test resolving - Good, Loads
next.config.jsfor flags that enable experimental SWC transforms - Good, SWC is faster than Babel
- Good, needs no additional configuration to be able to test UI code
- Bad, does not fully support ES6+ modules
Jest (with Babel)
Use Jest and Babel
- Good, Next.js is configured
- Bad, slower than SWC
- Bad, stylesheets and Image imports need to be mocked