I'm looking for a short story I saw on Reddit once, but apparently didn't save or bookmark. It's about how, in the far future, humanity finally achieves some technological singularity and "transcends" to a higher plane of existence. In doing so, however, humanity abandons dogs, their partners of millions of years of evolution. After doing so, dogs become the dominant intelligent species of life on Earth and develop advanced civilization and so on, with the focus of finally finding the humans, who the dogs believe are testing their worth. Dogs finally achieve their own technological transcendance many, many years later, locating the collective consciousness of humanity in the process. An avatar for humanity comes forth to deliver the lie that yes it was all a test, but after seeing all Dog has done to reunite with him, admits that humanity just discarded dog.
Dog is heartbroken, and its entire reality which formed the basis for the entire species' civilizational drive is shattered, but immediately after asks if they can still be friends, "because it was Dog" or something like that. Humanity agrees to be friends again with Dog and that is the end of the story.