https://github.com/gojob-1337/wait-for-assertion

A wrapper for asynchronous testing assertions
https://github.com/gojob-1337/wait-for-assertion

Last synced: 3 days ago
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A wrapper for asynchronous testing assertions

• Host: GitHub
• URL: https://github.com/gojob-1337/wait-for-assertion
• Owner: gojob-1337
• License: mit
• Created: 2019-05-23T12:49:45.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2023-01-03T22:28:52.000Z (almost 2 years ago)
• Last Synced: 2024-05-06T19:07:55.224Z (6 months ago)
• Language: TypeScript
• Homepage:
• Size: 720 KB
• Stars: 0
• Watchers: 6
• Forks: 0
• Open Issues: 13
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md

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README

        
# Wait for Assertion

A wrapper for asynchronous testing assertions.

## Getting started

```bash

yarn add @gojob/wait-for-assertion

# or

npm install @gojob/wait-for-assertion

```

## How

By "asynchronous assertions", we means Assertions that must be executed with a delay. The typical use case that we want to avoid is the following:

```typescript

await myFunctionWithAsyncSideEffects();

await new Promise(resolve => setTimeout(resolve, 1000)); // ❌ 🤢 🤮

expect(mySideEffectExists()).toBe(true);

```

`waitForAssertion` will run the given function (containing assertions) until it stops throwing exceptions (which means that it "passed"), or will throw a Timeout error.

`waitForAssertion` accepts up to three parameters:

```typescript

function waitForAssertion(

  assertion: () => any,

  timeoutDelay: number = 1000,

  intervalDelay: number = 100

);

```

- `assertion`: Closure containing asynchronous assertions to be made.

- `timeoutDelay`: _[1000ms]_ How long should the assertion be repeated until it passes (or times out).

- `intervalDelay`: _[100ms]_ How often should the assertion be repeated during `timeoutDelay`.

## Example

```typescript

import { waitForAssertion } from '@gojob/wait-for-assertion';

// [...]

it('should asynchronously update the value in Elasticsearch', async () => {

  await request(server)

    .put(endpointURL)

    .send(input)

    .expect(HttpStatus.NO_CONTENT);

  // the document is not immediatly available in Elasticsearch: wait

  await waitForAssertion(async () => {

    const { document } = await elasticsearchService.get(UserIndex, userId);

    return expect(document.firstName).toBe(updatedUser.firstName);

  });

});

```

## Credits

Developed by [VinceOPS](https://twitter.com/VinceOPS) at [Gojob](https://twitter.com/GojobT).  

Initial blog story: 🇫🇷 [article](https://vinceops.me/nest-e2e-tests-effets-de-bord/)