# Testing

Para realizar tests unitarios dentro de Rails y Vue se puede usar [Jest](https://jestjs.io/) y [Vue Test Utils](https://vue-test-utils.vuejs.org/). Como siempre, la [documentación de Vue](https://vuejs.org/v2/guide/unit-testing.html) es un buen punto de partida.

En proyectos nuevos Potassium ya incluye los archivos y la configuración necesaria para empezar a testear. En proyectos antiguos sigue los siguientes pasos para tener un ambiente listo para realizar pruebas de manera local.

```bash
> yarn add jest vue-jest babel-jest @vue/test-utils jest-serializer-vue babel-core@^7.0.0-bridge.0 --dev
```

```json
// https://vue-test-utils.vuejs.org/guides/#testing-single-file-components-with-jest
package.json
  "scripts": {
    "test": "jest",
    "test:watch": "jest --watch"
  },
  "jest": {
    "roots": [
      "app/javascript"
    ],
    "moduleDirectories": [
      "node_modules",
      "app/javascript"
    ],
    "moduleNameMapper": {
      "^@/(.*)$": "app/javascript/$1"
    },
    "moduleFileExtensions": [
      "js",
      "json",
      "vue"
    ],
    "transform": {
      "^.+\\\\.js$": "<rootDir>/node_modules/babel-jest",
      ".*\\\\.(vue)$": "<rootDir>/node_modules/vue-jest"
    },
    "snapshotSerializers": [
      "<rootDir>/node_modules/jest-serializer-vue"
    ]
  },
```

***

Para ejecutar los tests en un ambiente CI (como CircleCI), copia los cambios correspondientes de [bin/ci\_build](https://github.com/platanus/potassium/blob/ce9aa9e1ddd19c344b74afe5dfa3a4c7af866176/lib/potassium/assets/bin/cibuild.erb), [.circleci/config.yml](https://github.com/platanus/potassium/blob/ce9aa9e1ddd19c344b74afe5dfa3a4c7af866176/lib/potassium/assets/.circleci/config.yml.erb) y [docker-compose.ci](https://github.com/platanus/potassium/blob/ce9aa9e1ddd19c344b74afe5dfa3a4c7af866176/lib/potassium/assets/docker-compose.ci.yml)

***

```bash
> yarn test
 FAIL  config/webpack/test.js
  ● Test suite failed to run

    Your test suite must contain at least one test.
```

Un ejemplo de test básico usando el componente que instala el setup:

`App.vue`

```javascript
<template>
  <div id="app">
    <p>{{ message }}</p>
  </div>
</template>

<script>
export default {
  data: function () {
    return {
      message: "Hello Platanus!"
    }
  }
}
</script>

<style scoped>
p {
  font-size: 2em;
  text-align: center;
}
</style>
```

`App.spec.js`

```javascript
import { shallowMount } from '@vue/test-utils';
import App from './app.vue';

describe('app.vue', () => {
  it('displays message on load', () => {
    const wrapper = shallowMount(App);
    expect(wrapper.find('p').text()).toEqual('Hello Platanus!');
  });
});
```

```
 PASS  app/javascript/app.spec.js
  app.vue
    ✓ displays message on load (25ms)
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://la-guia.platan.us/stack/javascript/vue/testing.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.