E2E Tests: Add Child Blocks tests and test plugin

packages/e2e-tests/plugins/child-blocks.php

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+<?php
+/**
+ * Plugin Name: Gutenberg Test Child Blocks
+ * Plugin URI: https://github.com/WordPress/gutenberg
+ * Author: Gutenberg Team
+ *
+ * @package gutenberg-test-child-blocks
+ */
+
+/**
+ * Registers a custom script for the plugin.
+ */
+function enqueue_child_blocks_script() {
+	wp_enqueue_script(
+		'gutenberg-test-child-blocks',
+		plugins_url( 'child-blocks/index.js', __FILE__ ),
+		array(
+			'wp-blocks',
+			'wp-block-editor',
+			'wp-element',
+			'wp-i18n',
+		),
+		filemtime( plugin_dir_path( __FILE__ ) . 'child-blocks/index.js' ),
+		true
+	);
+}
+
+add_action( 'init', 'enqueue_child_blocks_script' );

packages/e2e-tests/plugins/child-blocks/index.js

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+( function() {
+	const { InnerBlocks } = wp.blockEditor;
+	const { createElement: el } = wp.element;
+	const { registerBlockType } = wp.blocks;
+
+	registerBlockType( 'test/child-blocks-unrestricted-parent', {
+		title: 'Child Blocks Unrestricted Parent',
+		icon: 'carrot',
+		category: 'text',
+
+		edit() {
+			return el(
+				'div',
+				{},
+				el( InnerBlocks )
+			);
+		},
+
+		save() {
+			return el(
+				'div',
+				{},
+				el( InnerBlocks.Content )
+			);
+		},
+	} );
+
+	registerBlockType( 'test/child-blocks-restricted-parent', {
+		title: 'Child Blocks Restricted Parent',
+		icon: 'carrot',
+		category: 'text',
+
+		edit() {
+			return el(
+				'div',
+				{},
+				el(
+					InnerBlocks,
+					{ allowedBlocks: [ 'core/paragraph', 'core/image' ] }
+				)
+			);
+		},
+
+		save() {
+			return el(
+				'div',
+				{},
+				el( InnerBlocks.Content )
+			);
+		},
+	} );
+
+	registerBlockType( 'test/child-blocks-child', {
+		title: 'Child Blocks Child',
+		icon: 'carrot',
+		category: 'text',
+
+		parent: [
+			'test/child-blocks-unrestricted-parent',
+			'test/child-blocks-restricted-parent',
+		],
+
+		edit() {
+			return el(
+				'div',
+				{},
+				'Child'
+			);
+		},
+
+		save() {
+			return el(
+				'div',
+				{},
+				'Child'
+			);
+		},
+	} );
+} )();

packages/e2e-tests/specs/editor/plugins/child-blocks.test.js

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+/**
+ * WordPress dependencies
+ */
+import {
+	activatePlugin,
+	closeGlobalBlockInserter,
+	createNewPost,
+	deactivatePlugin,
+	getAllBlockInserterItemTitles,
+	insertBlock,
+	openGlobalBlockInserter,
+} from '@wordpress/e2e-test-utils';
+
+describe( 'Child Blocks', () => {
+	beforeAll( async () => {
+		await activatePlugin( 'gutenberg-test-child-blocks' );
+	} );
+
+	beforeEach( async () => {
+		await createNewPost();
+	} );
+
+	afterAll( async () => {
+		await deactivatePlugin( 'gutenberg-test-child-blocks' );
+	} );
+
+	it( 'are hidden from the global block inserter', async () => {
+		await openGlobalBlockInserter();
+		await expect( await getAllBlockInserterItemTitles() ).not.toContain(
+			'Child Blocks Child'
+		);
+	} );
+
+	it( 'shows up in a parent block', async () => {
+		await insertBlock( 'Child Blocks Unrestricted Parent' );
+		await closeGlobalBlockInserter();
+		await page.waitForSelector(
+			'[data-type="test/child-blocks-unrestricted-parent"] .block-editor-default-block-appender'
+		);
+		await page.click(
+			'[data-type="test/child-blocks-unrestricted-parent"] .block-editor-default-block-appender'
+		);
+		await openGlobalBlockInserter();
+		const inserterItemTitles = await getAllBlockInserterItemTitles();
+		expect( inserterItemTitles ).toContain( 'Child Blocks Child' );
+		expect( inserterItemTitles.length ).toBeGreaterThan( 20 );
+	} );
+
+	it( 'display in a parent block with allowedItems', async () => {
+		await insertBlock( 'Child Blocks Restricted Parent' );
+		await closeGlobalBlockInserter();
+		await page.waitForSelector(
+			'[data-type="test/child-blocks-restricted-parent"] .block-editor-default-block-appender'
+		);
+		await page.click(
+			'[data-type="test/child-blocks-restricted-parent"] .block-editor-default-block-appender'
+		);
+		await openGlobalBlockInserter();
+		expect( await getAllBlockInserterItemTitles() ).toEqual( [
+			'Child Blocks Child',
+			'Image',
+			'Paragraph',
+		] );
+	} );
+} );