> Tests usually measure lots of things, and speed and accuracy / fluency in the topic is one.

Why are you trying to measure speed though?

I can't think of any situation where someone was like: you have exactly 1 minute to integrate this function, or else.

Fluency yes, but speed is a poor proxy for fluency.

Why is it a poor proxy? Someone who really understands the concepts and has the aptitude for it will get answers more quickly than someone who is shakier on it. The person who groks it less may be able to get to the answer, but needs to spend more time working through the problem. They're less good at calculus and should get a lower grade! Maybe they shouldn't fail Calc 101, but may deserve a B or (the horror) a C. Maybe that person will never get an A is calculus and that should be ok.

Joel Spolsky explained this well about what makes a good programmer[1]. "If the basic concepts aren’t so easy that you don’t even have to think about them, you’re not going to get the big concepts."

[1] https://www.joelonsoftware.com/2006/10/25/the-guerrilla-guid...