How do you assert matchers on nested object contents Somethi kotlinlang #kotest

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Title

l

Lukasz Kalnik

12/28/2021, 6:14 PM

How do you assert matchers on nested object contents? Something like capturing slots in MockK. E.g. I have an object like this:

Success(Either.Left(IOError(cause=com.google.gson.stream.MalformedJsonException)))

I want to assert certain things: • that the contents of

Success

is of type

Left

• that the contents of

Left

is of type

IOError

• that the

cause

is of type

MalformedJsonException

s

sam

12/28/2021, 6:23 PM

Are you using arrow ?

l

Lukasz Kalnik

12/28/2021, 6:25 PM

Yes

s

sam

12/28/2021, 6:25 PM

And Success here is a kotlin Result ?

l

Lukasz Kalnik

12/28/2021, 6:25 PM

No

It's a custom class from Retrofit I guess

But my question is more general

s

sam

12/28/2021, 6:26 PM

ok, well for things like Arrow, we offer matchers that will smart cast as well as return the contained value

l

Lukasz Kalnik

12/28/2021, 6:27 PM

What about the `IOError`'s

cause

property type?

s

sam

12/28/2021, 6:27 PM

val v = either.shouldBeLeft()
v shouldBe "whatever"

or

either.shouldBeLeft().shouldBe("whatever")

👍 1

l

Lukasz Kalnik

12/28/2021, 6:27 PM

Can I somehow extract it?

And assert that its type is

MalformedJsonException

?

I don't want to check equality, I just want to check the type of the

cause

property

s

sam

12/28/2021, 6:28 PM

either.shouldBeLeft().cause.shouldBeInstanceOf<MalformedJsonException>()

l

Lukasz Kalnik

12/28/2021, 6:28 PM

ah ok, thanks!

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