65: one assert per test

Is it ok to have more than one assert statement in a test?
I've seen articles that say no, you should never have more than one assert.
I've also seen some test code made almost unreadable due to trying to avoid more than one assert per test.

Where did this recommendation even come from? What are the reasons?
What are the downsides to both perspectives?

That's what we're going to talk about today.

Links:

• Twitter survey about multiple asserts/checks — Are multiple asserts/checks ok in an automated test?
• Multiple Asserts Are OK - Bill Wake
• pytest-check: A pytest plugin that allows multiple failures per test.