Add e2e test for the table block caption

packages/e2e-tests/specs/blocks/__snapshots__/table.test.js.snap

@@ -1,5 +1,11 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`Table allows a caption to be added 1`] = `
+"<!-- wp:table -->
+<table class=\\"wp-block-table\\"><caption>Caption!</caption><tbody><tr><td></td><td></td></tr><tr><td></td><td></td></tr></tbody></table>
+<!-- /wp:table -->"
+`;
+
 exports[`Table allows header and footer rows to be switched on and off 1`] = `
 "<!-- wp:table -->
 <table class=\\"wp-block-table\\"><thead><tr><th>header</th><th></th></tr></thead><tbody><tr><td>body</td><td></td></tr><tr><td></td><td></td></tr></tbody><tfoot><tr><td>footer</td><td></td></tr></tfoot></table>

packages/e2e-tests/specs/blocks/table.test.js

@@ -115,4 +115,19 @@ describe( 'Table', () => {
 		// Expect the table to have only a body with written content.
 		expect( await getEditedPostContent() ).toMatchSnapshot();
 	} );
+
+	it( 'allows a caption to be added', async () => {
+		await insertBlock( 'Table' );
+
+		// Create the table.
+		const createButton = await page.$x( "//div[@data-type='core/table']//button[text()='Create']" );
+		await createButton[ 0 ].click();
+
+		// Click the first cell and add some text.
+		await page.click( '.wp-block-table__caption-content' );
+		await page.keyboard.type( 'Caption!' );
+
+		// Expect the post to have the correct written content inside the table.
+		expect( await getEditedPostContent() ).toMatchSnapshot();
+	} );
 } );