Get started with custom builds

Add a test to the project

To create a build config that runs tests, you have to prepare your project by installing jest-expo and jest as dependencies. Run the following command:

Next, add a test script in package.json:

{
  "scripts": {
    %%placeholder-start%%... %%placeholder-end%%
    "test": "jest"
  },
  "jest": {
    "preset": "jest-expo",
    "transformIgnorePatterns": [
      "node_modules/(?!((jest-)?react-native|@react-native(-community)?)|expo(nent)?|@expo(nent)?/.*|@expo-google-fonts/.*|react-navigation|@react-navigation/.*|@unimodules/.*|unimodules|sentry-expo|native-base|react-native-svg)"
    ]
  }
}

For brevity, let's create an App.test.js at the root of your project and then add the following snippet:

import renderer from 'react-test-renderer';

import App from './App';

describe('<App />', () => {
  it('has 1 child', () => {
    const tree = renderer.create(<App />).toJSON();
    expect(tree.children.length).toBe(1);
  });
});

See Unit testing with Jest for more information about configuring the jest-expo package and additional configuration options such as transformIgnorePatterns.

Create a workflow

You must add a build config file in your project to create a workflow. Create a directory path .eas/build at the same level as eas.json. For example, if the eas.json file is at the root of your project, create the directory at that level. Both path and name of both directories are important for EAS Build to identify that a project contains a custom build config.

Inside it, you can create a new file called test.yml. This file contains the workflow config that you want to run. The filename is unimportant; you can name it whatever you want. The only requirement is that the file extension uses .yml.

This file will contain steps to run tests on the EAS Build service. It'll install all the required dependencies from the package.json file of your project and execute the npm test script.

Add the following workflow steps in the file:

build:
  name: Run tests
  steps:
    - eas/checkout
    - run:
        name: Install dependencies
        command: npm install
    - run:
        name: Run tests
        command: |
          echo "Running tests..."
          npm test

Add config property in eas.json

To use the custom build config, you must add the config property in eas.json. It contains the build config filename as the value you want to run on the EAS.

Let's create a new build profile called test under build to run the custom config from the test.yml file:

{
  "build": {
    %%placeholder-start%%... %%placeholder-end%%
    "test": {
      "config": "test.yml",
      "withoutCredentials": true
    },
}

Use the withoutCredentials option to skip the credentials setup on the CLI side, as they are not needed for running tests.

If you wish to use separate configs for each platform, you can create separate YAML config files for Android and iOS. For example:

{
  "build": {
    %%placeholder-start%%... %%placeholder-end%%
    "test": {
      "ios": {
        "config": "test-ios.yml",
      },
      "android": {
        "config": "test-android.yml",
      },
      "withoutCredentials": true
    },
}

Run build to test the workflow

To test the workflow, run the following command:

After the build is complete, you can verify that the npm test script was executed by checking the logs on the build details page.