Testing: add e2e test for the HTML block

test/e2e/specs/blocks/__snapshots__/html.test.js.snap

@@ -0,0 +1,8 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`HTML block can be created by typing "/html" 1`] = `
+"<!-- wp:html -->
+<p>Pythagorean theorem: 
+<var>a</var><sup>2</sup> + <var>b</var><sup>2</sup> = <var>c</var><sup>2</sup> </p>
+<!-- /wp:html -->"
+`;

test/e2e/specs/blocks/html.test.js

@@ -0,0 +1,26 @@
+/**
+ * Internal dependencies
+ */
+import {
+ clickBlockAppender,
+ getEditedPostContent,
+ newPost,
+} from '../../support/utils';
+
+describe( 'HTML block', () => {
+ beforeEach( async () => {
+ await newPost();
+ } );
+
+ it( 'can be created by typing "/html"', async () => {
+ // Create a Custom HTML block with the slash shortcut.
+ await clickBlockAppender();
+ await page.keyboard.type( '/html' );
+ await page.keyboard.press( 'Enter' );
+ await page.keyboard.type( '<p>Pythagorean theorem: ' );
+ await page.keyboard.press( 'Enter' );
+ await page.keyboard.type( '<var>a</var><sup>2</sup> + <var>b</var><sup>2</sup> = <var>c</var><sup>2</sup> </p>' );
+
+ expect( await getEditedPostContent() ).toMatchSnapshot();
+ } );
+} );