Add regression E2E test for the bug that caused some wp_options to ge…

…t corrupted data (#32797)

* Manually revert the relevant portions of #32229 in order to reproduce the wp_option data corruption bug

* Test regression for settings update corrupting some wp_options

* Cleanup

* Revert "Manually revert the relevant portions of #32229 in order to reproduce the wp_option data corruption bug"

This reverts commit 17eb33b.

* Add comment to remind us that to eventually add a similar test to core

packages/e2e-tests/specs/misc/settings.test.js

@@ -0,0 +1,42 @@
+/**
+ * WordPress dependencies
+ */
+import { visitAdminPage } from '@wordpress/e2e-test-utils';
+
+async function getOptionsValues( selector ) {
+	await visitAdminPage( 'options.php' );
+	return page.evaluate( ( theSelector ) => {
+		const inputs = Array.from( document.querySelectorAll( theSelector ) );
+		return inputs.reduce( ( memo, input ) => {
+			memo[ input.id ] = input.value;
+			return memo;
+		}, {} );
+	}, selector );
+}
+
+// It might make sense to include a similar test in WP core (or move this one over).
+// See discussion here: https://github.com/WordPress/gutenberg/pull/32797#issuecomment-864192088.
+describe( 'Settings', () => {
+	test( 'Regression: updating a specific option will only change its value and will not corrupt others', async () => {
+		// We won't select the option that we updated and will also remove some
+		// _transient options that seem to change at every update.
+		const optionsInputsSelector =
+			'form#all-options table.form-table input:not([id*="_transient"]):not([id="blogdescription"])';
+		const optionsBefore = await getOptionsValues( optionsInputsSelector );
+
+		await visitAdminPage( 'options-general.php' );
+		await page.type(
+			'input#blogdescription',
+			'Just another Gutenberg site'
+		);
+		await page.click( 'input#submit' );
+
+		const optionsAfter = await getOptionsValues( optionsInputsSelector );
+
+		Object.entries( optionsBefore ).forEach( ( optionBefore ) => {
+			const [ id ] = optionBefore;
+			const optionAfter = [ id, optionsAfter[ id ] ];
+			expect( optionAfter ).toStrictEqual( optionBefore );
+		} );
+	} );
+} );