How to "officially" distinguish "honest" resolution 1920*1080 from upscale 1280*720 -> 1920*1080?

Question

Video

Good afternoon! There is a certain IPTV provider that offers a certain TV channel with a resolution of 1080. The problem is that:
1) No one except this provider has this channel in 1080. Even from the site of the studio itself, broadcasting is in 720 resolution.
2) In my opinion, the picture does not pull at 1080.
And I had an idea that this provider (or someone in the chain from the content creator to him) is simply upscaling the video stream he has.
Is it possible to somehow conduct an examination to prove that this is really an upscale? (Or really "honest" 1080s?)

Answer 1

Take a screenshot, check here rest7.com/image_upscaled

Answer 2

Examination implies access to the stream transmission channel for the purpose of transmitting test signals over it and subsequent analysis of the results. I doubt that you have such access, but if you do, you should try passing standard test pictures through it, like the ones we use to test monitors. Among these pictures there are those that have sharp edges of the contours. The sharpness of these boundaries is especially well seen in monochrome b/w images. Here's one that fits:
Its central part consists of only black and white pixels. The boundaries between them should be considered with a magnification of 10 or more times. By blurring the boundaries, even a non-expert can easily distinguish 720, "stretched" to 1080, from "clean" 1080.