将t.Parallel（）放在测试顶部的实际好处是什么？

Question

The go testing package defines a Parallel() function:

Parallel signals that this test is to be run in parallel with (and only with) other parallel tests.

However when I searched the tests written for the standard library, I found only a few uses of this function.

My tests are pretty fast, and generally don't rely on mutating shared state, so I've been adding this, figuring it would lead to a speedup. But the fact it's not used in the standard library gives me pause. What is the practical benefit to adding t.Parallel() to your tests?

Answer 1

This seems to have been brought up first on the golang-dev group.

The initial request states:

"I'd like to add an option to run tests in parallel with gotest. My motivation comes from running selenium tests where each test is pretty much independent from each other but they take time."

The thread contains the discussion of the practical benefits.

It's really just for allowing you to run unrelated, long-running tests at the same time. It's not really used in the standard library as almost all of the functionality needs to be as fast as possible (some crypto exceptions etc.)

There was further discussion here and the commit is here