Add unit tests for HashingContext

[maxmutant]

This is part of issue #43440.
The unit tests should cover the basic use cases of HashingContext.

I thought about making tests for invalid input as well (e.g. call to update with an empty PackedByteArray), but all these cases are already handled with proper asserts, so I omitted them (as they would pollute the output with ERROR messages).

Ps.: This is my first contribution. So any feedback/critic is very welcome!

[Calinou]

but all these cases are already handled with proper asserts, so I omitted them (as they would pollute the output with ERROR messages).

You can surround the "invalid" code path with ERR_PRINT_OFF; and ERR_PRINT_ON;. This disables error reporting but still runs the code. (Try to put those macros as close as possible to the invalid code you need to run.)

[maxmutant]

Oh, ok. That's good to know, thanks!
I will add further test cases then.

[maxmutant]

I have added more tests that should cover the invalid use of HashingContext.

[maxmutant]

Made an update to current master to solve conflicts.

[Xrayez]

Cannot comment on the topic, but tests look good to me!

Needs another rebase...

[Xrayez]

Need to bump year to 2021 in headers: https://github.com/godotengine/godot/pull/43459/checks?check_run_id=1993702277.

[maxmutant]

Yeah just recognized it, thx!

Should be fine now.

[Faless]

This looks good 🏅 .

It would be nice to also add comparison to the actual known hashes.
I see the String hash functions are tested separately in tests/test_string.h so it feels like testing the same thing 2 times, but this specific test feels a bit incomplete without it.

That said, I don't have a strong opinion about it, so I'm going to approve anyway.

[maxmutant]

I'm with you.
I'll update the tests so they aren't repetitive with the one's of the String class.

[maxmutant]

The actual hashes are now used for comparison instead of the String hash functions.
So the tests should be independent from the one's of the String class.

Hope this makes more sense now :)

[Faless]

Great work, thanks!