Dannon Baker
19c54da423
frequently, and is more trouble than it has proved to be worth. For a component workbench, we're going to try storybook, which now has a nice vue integration instead. Reorg client docs. This all could use a once-over for content and tone.
2.6 KiB
Clearly document the intent of your test
Please remember that these tests are not for you. They're for the people who come after you. It will be a lot easier to modify, repair and upgrade your code if they can figure out what you were originally hoping to accomplish. Try to use as detailed 'expect' statements as possible -- overuse of 'toBeTruthy()' for example, can hide the intent of your test.
Add a couple of comments. Use variable names that mean something. Nobody's code is as self-documenting as they believe it to be.
Only test the public API that you define
Internal implementations come and go with library upgrades and new tech. But the point of the unit test is to make sure your units work as designed.... which means you need to... you know... design your code to work in units.
Separate your concerns and identify the developer-facing methods and functions you expect them to use. Test THOSE. Everything else should probably be considered an implementation detail.
The other side of the same coin is to test only the unit in question. If your component has a model that uses a service that touches Vuex, which then uses Axios to fetch some data -- don't test all that at once. Break things apart and mock functionality to isolate testing to units. End to end testing is a separate thing that shouldn't be attempted using spec tests in Jest.
Assume nobody cares how your code works, we just need to know that the public API you designed does work. If performance problems or new tech necessitate a re-write, these tests become a guide for the next implementation.
Writing a test file
Jest will try to test any file ending in "*.test.js". Please place your test files inside client/src folders right next to whatever files that they are testing.
Jest has extensive documentation on the expect API, mocking, and more on the official docs page, which will be your best resource here.
// yourcode.test.js
import { things } from "./yourcode.js";
describe("some module you wrote", () => {
let transientVariables;
let serviceInstances;
let testData;
beforeEach(() => {
// setup your code (if necessary)
});
afterEach(() => {
// teardown your code (so it doesn't ruin the next test)
});
it("should do something or other", () => {
expect(workflowNodeCount()).toBe(5);
});
});
Check out the Jest helper functions
We have created some common helpers for common testing scenarios.