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https://github.com/pngwn/svelte-test
Testing utilities for Svelte
https://github.com/pngwn/svelte-test
Last synced: about 2 months ago
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Testing utilities for Svelte
- Host: GitHub
- URL: https://github.com/pngwn/svelte-test
- Owner: pngwn
- Created: 2019-05-19T21:37:34.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2023-01-03T23:29:43.000Z (almost 2 years ago)
- Last Synced: 2024-10-14T13:03:32.733Z (2 months ago)
- Language: JavaScript
- Homepage:
- Size: 3.44 MB
- Stars: 25
- Watchers: 2
- Forks: 0
- Open Issues: 30
-
Metadata Files:
- Readme: README.md
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README
# svelte-test
Transforms and examples for testing Svelte components.
There are details on the transforms below. You can view example test setups in [`/examples/`](https://github.com/pngwn/svelte-test/tree/master/examples/).
---
- [I am using Jest](#svelte-testtransform)
- [I am not using Jest](#svelte-testrequire)
---
## svelte-test/transform
Install `jest` and `svelte-test`.
```bash
yarn add --dev jest svelte-test # or npm i -D jest
```
In your jest config file add `svelte-test/transform` as a transform for Svelte components (whatever file extension you use). Add any preprocessors to `globals.svelte.preprocess` and any custom compiler options to `globals.svelte.compilerOptions`. Your Jest config file will need to be a javascript file.
The `jest.config.js` should look something like this:
```js
module.exports = {
testPathIgnorePatterns: ['/node_modules/', '/cypress/'],
transform: {
'^.+\\.svelte$': 'svelte-test/transform',
},
globals: {
svelte: {
preprocess: preprocess(),
compilerOptions: {
accessors: true,
},
},
},
};
```
### babel?
You will probably need to install babel as well, to save you a lifetime of hell I will provide basic instructions.
Install `babel-jest`, `@babel/core`, and `@babel/preset-env`.
```bash
yarn add --dev babel-jest @babel/core @babel/preset-env #or npm i ...
```
Create a `babel.config.js` that looks like this:
```js
module.exports = function(api) {
api.cache(true);
return {
presets: [
[
'@babel/preset-env',
{
targets: {
node: 'current',
},
},
],
],
};
};
```
### success!
You can now do this in your tests:
```js
import App from '../App.svelte';
test('The component should exist', () => {
const component = new App({ target: document.body });
expect(component).toBeTruthy();
});
```
You may now go on with your life.
## svelte-test/require
If you are not using jest you can still hook into node `require`s and get back a real, _genuine_, compiled component. What you do with that component is your business.
Install `require-extension-hooks` and `svelte-test`:
```bash
yarn add --dev require-extension-hooks svelte-test # or npm i ...
```
Wherever you are doing your magic, import `require-extension-hooks` and `svelte-test/require`.
```js
const hooks = require('require-extension-hooks');
const svelte = require('svelte-test/require');
```
You need to pass the `svelte()` function the _absolute path_ to your preprocessors as the first argument and any compiler options as the second argument, I haven't completely thought through the API so this may change in the future. You can then `push` the svelte function as a require hook for your component file extension like so:
```js
const hooks = require('require-extension-hooks');
const svelte = require('svelte-test/require');
const { join } = require('path');
const preprocessors = join(__dirname, './less.js');
const compilerOptions = { accessors: true };
const extensionHook = svelte(preprocessors, compilerOptions);
hooks('.svelte').push(extensionHook);
// You can just require it
const App = require('./App.svelte');
// This is now a constructor function as expected.
const app = new App(options);
```