Well i was surprised when i took my 1st gen SE to Apple store. They have ran some tests on their own Iphones (in special case to make it more than just an iPhone). So my iPhone was laying down still and nothing was happening on it.It says that, yes, but I don't recall it doing so when I bought it. I was surprised because I was expecting to have to download and run an application or something. That is, unless they ran it silently and in the background using Safari, but I have no idea how.
But iPhones of the service worker had a tons of information going around and checking everything. SO they even knew the exact moments when my iPhone failed to receive charging. They gave me a new iPhone then. Just because their software have proven my words: phone fails to charge above 1%.
This is highly possible, that you even won't notice on your side, but they will have proper tests performed virtually.