Is there some way to assert that a function does not throw kotlinlang #atrium

Do you still need such a function? I agree with Kevin that usually such a use case should be handled by the test framework but let me know if you have a different use case and I can help you with a corresponding assertion function

charleskorn

12/09/2018, 10:16 PM

In my case I have some test cases that should throw (so I use

assert({ ... }).toThrow<...>()

), but I want to also make it clear for other cases that they should not throw - I can imply that it should succeed by just calling the function, but something like

assert({ ... }).toNotThrow()

makes it really clear what my intention is

(I’m testing an initialiser block that does some validation, so it doesn’t make sense to make an assertion about the return value)

robstoll

12/11/2018, 3:50 PM

In the simplest form you can use the following:

Copy code

fun <T : Throwable> Assert<T>.notToThrow () = this

charleskorn

12/11/2018, 3:53 PM

That won’t quite work - if I have a

Throwable

, then it’s already thrown

I need an assertion on a lambda

robstoll

12/11/2018, 3:56 PM

Ah... sorry, I am writing from my phone and did not have the code at hand. Make the above an extension function of: ThrowableThrown.Builder

charleskorn

12/11/2018, 3:57 PM

OK, I’ll give that a go

Thanks!

robstoll

12/11/2018, 3:59 PM

Wait... I am pretty sure you need to check that exception is null

It's a bit cumbersome on the phone, I'll check it later. Also notice that my slack notifications seem to be broken. Did not get any notice about your question or this reply.

I guess it's a bit more complicated than I wrote. In the meantime you could use:

Copy code

fun Assert<() -> Any?>.notToThrow () = subject ()

Btw. good idea, I opened a feature request: https://github.com/robstoll/atrium/issues/53

Here the solution for ThrowableThrownBuilder:

Copy code

fun ThrowableThrown.Builder.notToThrow() = act()

0.8.0-alpha contains a

notToThrow()

function

charleskorn

01/20/2019, 1:05 AM

Great, I’ll try that now

8 Views