What makes you think that it's not humanly possible? Medical residents do similar hours. It's only been in the last 200 or so years that the 40 hour work week was more normal.
To answer your question though; About 45 to 60 hours a week can be spent testing various things depending on what needs to be done. It's not a constant flow of testing testing though, I'd probably say at least a few hours of each day is spent semi idle. It can be waiting for feedback or clarification from the devs, or a compilation (which can take up to 55 minutes for a release build of the largest package, but require 3 hours to take it from the final tested version to managers sending out the release email to the public). In other cases it's doing the secondary tasks for testing; setup and teardown, writing reports, hardware changes, etc.
10 to 20 hours a week is spent working on user facing documentation. Some of the time it's just editing what someone else wrote but most of the time it's compiling notes from bug reports, test case results, feature documents, and trying to compress all that information into a more easy to digest format.
About 8 to 16 hours a week is spent reviewing test cases. In most cases it's just making sure that the cases are still relevant and accurate. It is rather tedious and because of that I think no one else wants to do it, but it is a necessary task as letting it slide causes a great deal of confusion for all. There's some 300 to 400 manual test cases at any given time that cannot be readily automated.
Some 2 to 5 hours a week is spent on administrative overhead. Meetings, email, etc.
Beyond that it varies on what odd jobs need to be done around the office, which. Most of the time it's minor things but it can sometimes turn a larger effort, such as a hardware audit.
Keep in mind that 60 to 90 hours a week is a range, but most of the time it hovers closer to 60. Higher times only occur every two or three months or so.
Doctors and medical staff treat human lives and I don't think they are comparable to an office job. They also get paid a lot for that (at least in the US)
I don't know how someone can focus with that time schedule and I cannot see how I could handle that. I have so many other stuff in my life that I could not see myself committing to that, unless maybe in the case of having my own business or actually thinking that doing that (still, only for a limited amount of time) will open up great possibilities (maybe I strongly believe in the start up I work for). Especially not for 40k/year.
Can't really comment on whether it's humane, that's a debate left to people smarter then me.
Like I said, there's pretty significant downtime, it's not all go all the time. Weekend and evening work is at a fairly relaxed pace as well and is free of distractions.
It helps if you do not have hobbies, friends, dependents, a partner, and a family that is quite fine with not seeing you often, with no realistic possibility of any of that changing in the future. It would be much more difficult if any of those factors were different.
To answer your question though; About 45 to 60 hours a week can be spent testing various things depending on what needs to be done. It's not a constant flow of testing testing though, I'd probably say at least a few hours of each day is spent semi idle. It can be waiting for feedback or clarification from the devs, or a compilation (which can take up to 55 minutes for a release build of the largest package, but require 3 hours to take it from the final tested version to managers sending out the release email to the public). In other cases it's doing the secondary tasks for testing; setup and teardown, writing reports, hardware changes, etc.
10 to 20 hours a week is spent working on user facing documentation. Some of the time it's just editing what someone else wrote but most of the time it's compiling notes from bug reports, test case results, feature documents, and trying to compress all that information into a more easy to digest format.
About 8 to 16 hours a week is spent reviewing test cases. In most cases it's just making sure that the cases are still relevant and accurate. It is rather tedious and because of that I think no one else wants to do it, but it is a necessary task as letting it slide causes a great deal of confusion for all. There's some 300 to 400 manual test cases at any given time that cannot be readily automated.
Some 2 to 5 hours a week is spent on administrative overhead. Meetings, email, etc.
Beyond that it varies on what odd jobs need to be done around the office, which. Most of the time it's minor things but it can sometimes turn a larger effort, such as a hardware audit.
Keep in mind that 60 to 90 hours a week is a range, but most of the time it hovers closer to 60. Higher times only occur every two or three months or so.