[RFC] Unit Testing

[mertyildiran]

Add assert and tests keyword to the grammar. Add -t/--test CLI option. Consider the above Chaos program file:

dev.kaos:

num def sum(num a, num b)
    num c = a + b
    return c
end

print "hello world"

tests:
assert sum(3, 5) == 8

When you run it with chaos dev.kaos it prints hello world. But when you run it with chaos -t dev.kaos it does not print hello world but instead executes the code below the tests: tag. If the assertion fails exits with a non-zero code.

Optionally; warn user if there are no assertions on sum function when they run chaos dev.kaos like:

$ chaos dev.kaos
Chaos Warning: `sum` function is untested!
hello world

Add a CLI option to suppress these warnings.

[naltun]

I really like this idea:
$ chaos --test/-t <file>

I say let's get this in. It reminds me of how Zig programmers code (tests in the same file, and can be invoked via the CLI). I really like this.

$ chaos dev.kaos
Chaos Warning: `sum` function is not tested!
hello world

We can also change the wording to function is unused or untested!. I feel like this is better, because Chaos is built to encourage testing, but not everyone will want to write tests, especially for small programs. Adding unused seems a bit more semantically appropriate for certain cases.

[mertyildiran]

@naltun I've updated the description to <FUNCTION_NAME> function is untested! format. Do you suggest to add another keyword like unused to ignore untested function warnings? Like a function decorator:

@unused
num def sum(num a, num b)
    num c = a + b
    return c
end

such that the Chaos Warning: sum function is not tested! message will be suppressed?