https://github.com/op-engineering/op-test
Simple in-app testing framework for React Native
https://github.com/op-engineering/op-test
Last synced: 2 months ago
JSON representation
Simple in-app testing framework for React Native
- Host: GitHub
- URL: https://github.com/op-engineering/op-test
- Owner: OP-Engineering
- License: mit
- Created: 2025-02-04T08:13:42.000Z (about 1 year ago)
- Default Branch: main
- Last Pushed: 2025-09-07T13:23:55.000Z (8 months ago)
- Last Synced: 2025-09-07T15:20:04.727Z (8 months ago)
- Language: TypeScript
- Size: 9.23 MB
- Stars: 16
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
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README
# op-test
A lightweight, in-app testing framework for React Native applications.
## Motivation
You can think of op-test as a half-way between a Detox (UI e2e test) and Jest (runs in a Node environment). It's specially useful for library authors that depend on native libraries or some sort of runtime behavior that requires a simulator/emulator/device to assert correct functionality. It's specially suited to test JSI enabled libraries as testing JSI/TurboModules/NitroModules functions require the whole the React Native app to have started.
## Installation
```sh
npm install --save @op-engineering/op-test
```
## Usage
Import the testing utilities and write your tests:
```tsx
import { describe, it, expect } from '@op-engineering/op-test';
describe('Example', () => {
it('should work', () => {
expect(1 + 1).toBe(2);
});
});
```
You can then call the `runTests` function which will run all the functions registered under the `describe` blocks:
```ts
import {runTests} from '@op-engineering/op-test`;
const results = await runTests()
```
### Available Functions
- `describe(name: string, fn: () => void)`: Group related tests
- `it(name: string, fn: TestFunction)`: Define a test case
- `expect(value)`: Create assertions with:
- `.toBe(expected)`: Strict equality
- `.toEqual(expected)`: Loose equality
- `.not.toBe(expected)`: Negative strict equality
- `.not.toEqual(expected)`: Negative loose equality
- `.resolves`: For testing promises
- `.rejects`: For testing promise rejections
### Hooks
- `beforeAll(fn)`: Run before all tests in a describe block
- `beforeEach(fn)`: Run before each test
- `afterAll(fn)`: Run after all tests in a describe block
- `afterEach(fn)`: Run after each test
### Display Results
Use the `displayResults` component to show test results in your app in a visual way:
```tsx
import { runTests, displayResults } from '@op-engineering/op-test';
export default function App() {
const [result, setResult] = useState(null);
useEffect(() => {
runTests().then(setResult);
}, []);
return displayResults(result);
}
```
### CI
You probably want to automate your in-app tests in your CI. For this you can pass the DescribeBlock to the `allTestsPassed` function, it will return a boolean that indicates if all tests have passed. You can this automate this in various ways in your CI. My favorite is starting and in-app http server, exposing a single endpoint. From your CI you can then start the app, query this endpoint (over and over until it returns a reponse). Here is a snippet how to do this.
Server code:
```ts
import { BridgeServer } from 'react-native-http-bridge-refurbished';
let testsPassed: boolean | null = null;
const server = new BridgeServer('http_service', true);
server.get('/ping', async (_req, _res) => {
return { message: 'pong' };
});
server.get('/results', async (_req, _res) => {
return { testPassed };
});
server.listen(9000);
export function startServer() {
return server;
}
export function stopServer() {
server.stop();
}
export function setServerTestPassed(r: boolean) {
testsPassed = r;
}
```
Then to run your tests:
```tsx
import {
runTests,
displayResults,
allTestsPassed,
} from '@op-engineering/op-test';
import { startServer, setServerTestPassed } from './server';
export default function App() {
const [result, setResult] = useState(null);
useEffect(() => {
runTests().then((newResults) => {
setServerTestPassed(allTestsPassed(newResults));
setResult(newResults);
});
startServer();
}, []);
return displayResults(result);
}
```
The CI code is left as an exercise to the reader, just curl the device ip until you get a response.
## License
MIT