I have tried sending this message by email twice, and both times it seems to have disappeared. So I'm commenting via the web, and my apologies in advance if the message shows up later.

*****

> There are almost 500 occurrences of "is true".

We can worry about them if and when somebody raises them as a "bug
report" or feature request. Without reading each one in context, I have
no idea whether they are good, bad or indifferent. Doing a massive
search and replace would be a bad idea.

Right now we have a simple feature request: improve the assertTrue and
assertFalse messages. There is a simple way to improve them. We don't
have to touch any other message, just these two.

Personally, I prefer "truthy and falsey" or "true-like and false-like"
over "true and false" to distinguish between "duck-typed bools" and the
actual bool singletons True and False. But I don't prefer them enough to
fight over the terms. If you prefer "true and false", that's okay with
me too :-)

"False is not true" suggests to the user that the test is doing an
identity check. We have proof from the OP's bug report that at least one
person thought that. I had to read the source code to check that it doesn't.

A better failure message would be helpful to make it clear that it
checks by value not identity ``if value is True``.