Scripts: Provide the default configuration for the test command

It is used in the case when the project does not have a config for Jest or Babel

lerna.json

@@ -1,5 +1,12 @@
 {
 	"lerna": "2.8.0",
+	"commands": {
+		"publish": {
+			"ignore": [
+				"**/test/*.js"
+			]
+		}
+	},
 	"packages": [
 		"packages/*"
 	],

package.json

@@ -28,7 +28,7 @@
 		"prebuild": "check-node-version --package",
 		"build": "node ./scripts/build.js",
 		"postinstall": "lerna bootstrap --hoist && ./scripts/create-symlinks.sh && npm run build",
-		"test": "wp-scripts test",
+		"test": "wp-scripts test-unit",
 		"test:coverage": "npm run test -- --coverage",
 		"test:coverage-ci": "npm run test -- --coverage && codecov",
 		"test:watch": "npm run test -- --watch",

packages/scripts/README.md

@@ -16,9 +16,9 @@ This is a CLI and exposes a binary called `wp-scripts` so you can call it direct
 ```json
 {
 	"scripts": {
-		"test": "wp-scripts",
-		"test:help": "wp-scripts --help",
-		"test:watch": "wp-scripts --watch"
+		"test": "wp-scripts test-unit",
+		"test:help": "wp-scripts test-unit --help",
+		"test:watch": "wp-scripts test-unit --watch"
 	}
 }
 ```
@@ -30,9 +30,9 @@ This is how you execute those scripts using the presented setup:
 
 ## Available Scripts
 
-### `wp-scripts test`
+### `wp-scripts test-unit`
 
-Launches the test runner. It uses [Jest](https://facebook.github.io/jest/) behind the scenes and you are able to utilize all of its [CLI options](https://facebook.github.io/jest/docs/en/cli.html). You can also run `./node_modules/.bin/wp-scripts --help` or `npm run test:help` (if you use `package.json` setup shared above) to view all of the available options.
+Launches the test runner. It uses [Jest](https://facebook.github.io/jest/) behind the scenes and you are able to utilize all of its [CLI options](https://facebook.github.io/jest/docs/en/cli.html). You can also run `./node_modules/.bin/wp-scripts test-unit --help` or `npm run test:help` (if you use `package.json` setup shared above) to view all of the available options.
 
 ## Inspiration
 

packages/scripts/bin/wp-scripts.js

@@ -1,38 +1,10 @@
 #!/usr/bin/env node
 
-const spawn = require( 'cross-spawn' );
+/**
+ * Internal dependencies
+ */
+const { getCliArgs, spawnScript } = require( '../utils' );
 
-const allowedScripts = [ 'test' ];
-const [ scriptName, ...nodeArgs ] = process.argv.slice( 2 );
+const [ scriptName, ...nodesArgs ] = getCliArgs();
 
-if ( allowedScripts.indexOf( scriptName ) === -1 ) {
-	console.log( 'Unknown script "' + scriptName + '".' );
-	console.log( 'Perhaps you need to update @wordpress/scripts?' );
-	process.exit( 1 );
-}
-
-const result = spawn.sync(
-	'node',
-	[
-		require.resolve( `../scripts/${ scriptName }-script`  ),
-		...nodeArgs
-	],
-	{ stdio: 'inherit' }
-);
-if ( result.signal ) {
-	if ( result.signal === 'SIGKILL' ) {
-		console.log(
-			'The build failed because the process exited too early. ' +
-			'This probably means the system ran out of memory or someone called ' +
-			'`kill -9` on the process.'
-		);
-	} else if ( result.signal === 'SIGTERM' ) {
-		console.log(
-			'The build failed because the process exited too early. ' +
-			'Someone might have called `kill` or `killall`, or the system could ' +
-			'be shutting down.'
-		);
-	}
-	process.exit( 1 );
-}
-process.exit( result.status );
+spawnScript( scriptName, nodesArgs );

packages/scripts/config/babel-transform.js

@@ -0,0 +1,8 @@
+/**
+ * External dependencies
+ */
+const babelJest = require( 'babel-jest' );
+
+module.exports = babelJest.createTransformer( {
+	presets: [ '@wordpress/default' ],
+} );

packages/scripts/config/jest.config.js

@@ -0,0 +1,27 @@
+/**
+ * External dependencies
+ */
+const path = require( 'path' );
+
+/**
+ * Internal dependencies
+ */
+const {
+	hasProjectFile,
+	hasPackageProp,
+} = require( '../utils' );
+
+const jestConfig = {
+	preset: '@wordpress/jest-preset-default'
+};
+
+const hasBabelConfig = hasProjectFile( '.babelrc' ) ||
+	hasPackageProp( 'babel' );
+
+if ( ! hasBabelConfig ) {
+	jestConfig.transform = {
+		'^.+\\.js$': path.join( __dirname, 'babel-transform' ),
+	};
+}
+
+module.exports = jestConfig;

packages/scripts/package.json

@@ -23,14 +23,19 @@
 	},
 	"files": [
 		"bin",
-		"scripts"
+		"config",
+		"scripts",
+		"utils"
 	],
 	"bin": {
 		"wp-scripts": "./bin/wp-scripts.js"
 	},
 	"dependencies": {
+		"@wordpress/babel-preset-default": "^1.0.2",
+		"@wordpress/jest-preset-default": "^1.0.0",
 		"cross-spawn": "^5.1.0",
-		"jest": "^22.0.4"
+		"jest": "^22.0.4",
+		"read-pkg-up": "^3.0.0"
 	},
 	"publishConfig": {
 		"access": "public"

packages/scripts/scripts/test-unit.js

@@ -0,0 +1,39 @@
+// Do this as the first thing so that any code reading it knows the right env.
+process.env.BABEL_ENV = 'test';
+process.env.NODE_ENV = 'test';
+
+// Makes the script crash on unhandled rejections instead of silently
+// ignoring them. In the future, promise rejections that are not handled will
+// terminate the Node.js process with a non-zero exit code.
+process.on( 'unhandledRejection', err => {
+	throw err;
+} );
+
+/**
+ * External dependencies
+ */
+const jest = require( 'jest' );
+
+/**
+ * Internal dependencies
+ */
+const {
+	getCliArgs,
+	hasCliArg,
+	hasProjectFile,
+	hasPackageProp,
+} = require( '../utils' );
+
+const args = getCliArgs();
+
+const hasJestConfig = hasCliArg( '-c' ) ||
+	hasCliArg( '--config' ) ||
+	hasProjectFile( 'jest.config.js' ) ||
+	hasProjectFile( 'jest.config.json' ) ||
+	hasPackageProp( 'jest' );
+
+const config = ! hasJestConfig
+		? [ '--config', JSON.stringify( require( '../config/jest.config' ) ) ]
+		: [];
+
+jest.run( [ ...config, ...args ] );

packages/scripts/utils/index.js

@@ -0,0 +1,81 @@
+/**
+ * External dependencies
+ */
+const spawn = require( 'cross-spawn' );
+const { existsSync, realpathSync } = require( 'fs' );
+const path = require( 'path' );
+const readPkgUp = require( 'read-pkg-up' );
+
+/**
+ * Internal dependencies
+ */
+const { exit, getCliArgs, getCurrentWorkingDirectory } = require( './process' );
+
+const first = list => list[ 0 ];
+
+const hasCliArg = ( arg ) => getCliArgs()
+	.some( ( value ) => first( value.split( '=' ) ) === arg );
+
+const { pkg, path: pkgPath } = readPkgUp.sync( {
+	cwd: realpathSync( getCurrentWorkingDirectory() ),
+} );
+
+const appDirectory = path.dirname( pkgPath );
+
+const fromProjectRoot = ( fileName ) => path.join( appDirectory, fileName );
+
+const hasProjectFile = ( fileName ) => existsSync( fromProjectRoot( fileName ) );
+
+const fromScriptsRoot = ( scriptName ) => path.join( path.dirname( __dirname ), 'scripts', `${ scriptName }.js` );
+
+const hasScriptFile = ( scriptName ) => existsSync( fromScriptsRoot( scriptName ) );
+
+const hasPackageProp = ( prop ) => pkg && pkg.hasOwnProperty( prop );
+
+const handleSignal = ( signal ) => {
+	if ( signal === 'SIGKILL' ) {
+		console.log(
+			'The build failed because the process exited too early. ' +
+			'This probably means the system ran out of memory or someone called ' +
+			'`kill -9` on the process.'
+		);
+	} else if ( signal === 'SIGTERM' ) {
+		console.log(
+			'The build failed because the process exited too early. ' +
+			'Someone might have called `kill` or `killall`, or the system could ' +
+			'be shutting down.'
+		);
+	}
+	exit( 1 );
+};
+
+const spawnScript = ( scriptName, args ) => {
+	if ( ! hasScriptFile( scriptName ) ) {
+		console.log( 'Unknown script "' + scriptName + '".' );
+		console.log( 'Perhaps you need to update @wordpress/scripts?' );
+		exit( 1 );
+	}
+
+	const { signal, status } = spawn.sync(
+		'node',
+		[
+			fromScriptsRoot( scriptName ),
+			...args
+		],
+		{ stdio: 'inherit' }
+	);
+
+	if ( signal ) {
+		handleSignal( signal );
+	}
+
+	exit( status );
+};
+
+module.exports = {
+	getCliArgs,
+	hasCliArg,
+	hasProjectFile,
+	hasPackageProp,
+	spawnScript,
+};

packages/scripts/utils/process.js

@@ -0,0 +1,7 @@
+const getCliArgs = () => process.argv.slice( 2 );
+
+module.exports = {
+	exit: process.exit,
+	getCliArgs,
+	getCurrentWorkingDirectory: process.cwd,
+};

packages/scripts/utils/test/index.js

@@ -0,0 +1,54 @@
+jest.mock( '../process', () => {
+	const process = require.requireActual( '../process' );
+
+	return Object.keys( process ).reduce(
+		( accumulator, methodName ) => ( {
+			...accumulator,
+			[ methodName ]: jest.spyOn( process, methodName ),
+		} ),
+		{},
+	);
+} );
+
+/**
+ * Internal dependencies
+ */
+import {
+	getCliArgs,
+	hasCliArg,
+} from '../';
+import { getCliArgs as getCliArgsMock } from '../process';
+
+describe( 'utils', () => {
+	describe( 'getCliArgs', () => {
+		test( 'should have function defined', () => {
+			expect( getCliArgs() ).toBeDefined();
+		} );
+	} );
+
+	describe( 'hasCliArg', () => {
+		beforeAll( () => {
+			getCliArgsMock.mockReturnValue( [ '-a', '--b', '--config=test' ] );
+		} );
+
+		afterAll( () => {
+			getCliArgsMock.mockReset();
+		} );
+
+		test( 'should return false when no args passed', () => {
+			getCliArgsMock.mockReturnValueOnce( [] );
+
+			expect( hasCliArg( '--no-args' ) ).toBe( false );
+		} );
+
+		test( 'should return false when checking for unrecognized arg', () => {
+			expect( hasCliArg( '--non-existent' ) ).toBe( false );
+		} );
+
+		test( 'should return true when CLI arg found', () => {
+			expect( hasCliArg( '-a' ) ).toBe( true );
+			expect( hasCliArg( '--b' ) ).toBe( true );
+			expect( hasCliArg( '--config' ) ).toBe( true );
+		} );
+	} );
+} );