While planning testing suits and approaches, it's vital to consider that the apps are multiplatform. The same elements will look differently on mobile platforms and on desktops and must be adapted accordingly. That is especially true for correctly displaying UI/UX elements. Without testing that aspect, you might end up with an app having a broken layout. For checking an app's functioning under realistic conditions, testers need a predefined pool of real devices or, at minimum, emulators in a browser.
Your visitors need to feel comfortable navigating your website, so don't disappoint them.
Your professional testing team will focus on smoothing out user interaction with page components and conduct not only formal testing but also exploratory testing.
Developers of SPAs commonly use JavaScript, and your tester should be aware of that. Styles applied to page components are permanent, and related testing issues will pop up repeatedly if not addressed on time. QA and testing teams often stick to the Agile methodology, and if one team misses errors, other teams will run into the same errors later. That makes thorough professional testing mandatory.
SPAs are limited in page reloading capabilities. If you own e-commerce websites, the number of events on page and user interaction scenarios will multiply dramatically. Your testing team should verify the work of each element and ensure the events on the page go in line with the documentation.