svelte/test/runtime/samples/binding-textarea/_config.js

export default {
	data: {
		value: 'some text'
	},

	html: `
		<textarea></textarea>
		<p>some text</p>
	`,

	test ( assert, component, target, window ) {
		const textarea = target.querySelector( 'textarea' );
		assert.equal( textarea.value, 'some text' );

		const event = new window.Event( 'input' );

		textarea.value = 'hello';
		textarea.dispatchEvent( event );

		assert.htmlEqual( target.innerHTML, `
			<textarea></textarea>
			<p>hello</p>
		` );

		component.set({ value: 'goodbye' });
		assert.equal( textarea.value, 'goodbye' );
		assert.htmlEqual( target.innerHTML, `
			<textarea></textarea>
			<p>goodbye</p>
		` );
	}
};