[WOOTAX-294] Guard against missing Store API extension data in store notices

On WooCommerce versions without StoreApi support the blocks integration
still registers the script, but the Store API extension never adds the
woocommerce-services key to the cart extensions data, and the notices
effect crashed reading it.

Author: Abdalsalaam

client/components/store/notices/store-notices.js

@@ -50,8 +50,11 @@ export const StoreNotices = ( {
 				return;
 			}
 
-			// Get new notices from the API response.
-			const newNotices = extensions[ 'woocommerce-services' ].notices;
+			// Get new notices from the API response. The extension data is
+			// missing on WooCommerce versions where the Store API extension
+			// is not registered.
+			const wcservicesData = extensions[ 'woocommerce-services' ];
+			const newNotices     = ( wcservicesData && wcservicesData.notices ) || [];
 
 			if ( 0 === newNotices.length ) {
 				return;

client/components/store/notices/test/store-notices.js

@@ -0,0 +1,83 @@
+/** @format */
+
+/**
+ * External dependencies
+ */
+import React from 'react';
+import { mount } from 'enzyme';
+
+describe( 'StoreNotices', () => {
+	let createNotice;
+	let removeNotices;
+	let StoreNotices;
+
+	const usCart = { shippingAddress: { country: 'US', state: 'CA', postcode: '94105' } };
+
+	beforeEach( () => {
+		jest.resetModules();
+
+		createNotice = jest.fn();
+		removeNotices = jest.fn();
+
+		global.window.wp = {
+			element: { useEffect: React.useEffect },
+			data: {
+				useDispatch: () => ( { createNotice, removeNotices } ),
+				useSelect: () => [],
+			},
+		};
+
+		( { StoreNotices } = require( '../store-notices' ) );
+	} );
+
+	afterEach( () => {
+		delete global.window.wp;
+	} );
+
+	it( 'creates notices from the extension data for US addresses', () => {
+		const extensions = {
+			'woocommerce-services': {
+				notices: [ { type: 'error', message: 'ZIP could not be validated.' } ],
+			},
+		};
+
+		mount( <StoreNotices extensions={ extensions } cart={ usCart } /> );
+
+		expect( createNotice ).toHaveBeenCalledWith(
+			'error',
+			'ZIP could not be validated.',
+			expect.objectContaining( { context: 'wc/cart' } )
+		);
+	} );
+
+	it( 'does not create notices for non-US addresses', () => {
+		const extensions = {
+			'woocommerce-services': {
+				notices: [ { type: 'error', message: 'ZIP could not be validated.' } ],
+			},
+		};
+		const caCart = { shippingAddress: { country: 'CA', state: 'ON', postcode: 'M5V 2T6' } };
+
+		mount( <StoreNotices extensions={ extensions } cart={ caCart } /> );
+
+		expect( createNotice ).not.toHaveBeenCalled();
+	} );
+
+	it( 'renders without crashing when the extension data is missing', () => {
+		// Old WooCommerce versions register the blocks integration but not the
+		// Store API extension, so extensions has no woocommerce-services key.
+		expect( () => {
+			mount( <StoreNotices extensions={ {} } cart={ usCart } /> );
+		} ).not.toThrow();
+
+		expect( createNotice ).not.toHaveBeenCalled();
+	} );
+
+	it( 'renders without crashing when the notices key is missing', () => {
+		expect( () => {
+			mount( <StoreNotices extensions={ { 'woocommerce-services': {} } } cart={ usCart } /> );
+		} ).not.toThrow();
+
+		expect( createNotice ).not.toHaveBeenCalled();
+	} );
+} );