what makes you think that the 95% were actually tested? In fact if they were in close contact, they were put into
restricted quarantine, which meant they couldn't come out at all, someone had to bring supplies to their door, and after they opened the door the seal was replaced. over and over.
China knew they couldn't test 11 million people, and they knew they couldn't contain the virus is they let anyone who had been in close contact and might transmit the virus travel elsewhere. So that's why they locked down a city three times the size of Los Angeles (about twice the same physical geography) and still more people by 1/3 than New York and again twice the geography.
So, you close all entries, exits, public transportation, and then you take it down to housing area and street level.
The Chinese have never said they tested everyone in Wuhan, that would have been impossible to pull off. But they knew the primary villages, and the targeted areas where the virus was spreading from, and focused nearly all of their attention there.
Imagine living in Wuhan and being no where near that (as I've said before, Wuhan is actually THREE cities in one. Wuchang (where Wuhan get's its "Wu"), Hankou (where the 'han' comes from) and Hanyang. It has a surface area of 590sq miles just in the URBAN area. And 3200 square miles including the areas that are part of Wuhan CITY, but not Hubei province (large cities in China act like mini provinces with outer districts).