Hey i want to test observer in mockk. Anyone know how to do that. ```viewModel.onDownloadErrorLiveDa...

# mockk

[Vivek Modi]

Hey i want to test observer in mockk. Anyone know how to do that.

viewModel.onDownloadErrorLiveData.observe(this, { consumable ->
           some code
        })

[Matt Thompson]

You can get a reference to arguments passed in with capture in a verify block or in an answers block. Then just manually invoke the observer.

[Vivek Modi]

@Matt Thompson thanks for your reply. I am new in this library. I didn't get the reference or example. Can you please give me the example if possible. It would be great pleasure for me.

[Matt Thompson]

Sorry not on a proper keyboard but I'll try...

```lateinit var observer : Observer
every { mockLiveData.observe(any(), any()) } answers { observer = secondArg() as Observer }

[Matt Thompson]

something like that

[Vivek Modi]

@Matt Thompson

private fun yo(){
    viewModel.consentTag.observe(this, Observer { type ->
        typeText.text = type
    })
}

this is my function

[Vivek Modi]

import androidx.lifecycle.Observer

which import i need to use

[Vivek Modi]

@Test
fun `yo `() {
    every { mockViewModel.consentTag.observe(any(), any()) } answers {
        observer = secondArg() as Observer
    }

}

it giving error

[Matt Thompson]

you need to add the generic type of the LiveData

[Matt Thompson]

i.e. Observer<TypeHere>

[Vivek Modi]

okk

[Vivek Modi]

it fixed on complaining in observer issue

[Vivek Modi]

it again complaining this @Matt Thompson

[Vivek Modi]

ConsentType is enum class

[Matt Thompson]

yeah when you cast it using as you also need to define the type

[Matt Thompson]

or alternatively I believe secondArg takes a type argument, you could try putting it there

[Vivek Modi]

Sorry for again asking this

[Vivek Modi]

observer = secondArg() as ConsentType

[Vivek Modi]

like this ?

[Matt Thompson]

no, as Observer<ConsentType>

[Matt Thompson]

the actual type of the lambda that you’re passing in as the second argument of the observe function is Observer<ConsentType> - kotlin allows you to write it as a lambda with SAM conversion

[Vivek Modi]

and little bit confuse

private fun yo(){
    viewModel.consentTag.observe(this, Observer { type ->
        typeText.text = type
    })
}

how can i set value type in typeText

[Matt Thompson]

once you have the reference to the observer you can manually invoke onChanged

[Vivek Modi]

@Matt Thompson like this

@Test
    fun `yo `() {
        val value = ConsentType.GENERAL
        every { mockViewModel.consentTag.observe(any(), any()) } answers {
            observer = secondArg() as Observer<ConsentType>
        }
        observer.onChanged(value)
        consentActivity.yo()
        verify { mockTextView.tag = value }
    }

[Vivek Modi]

it gives error kotlin.UninitializedPropertyAccessException: lateinit property observer has not been initialized

[Matt Thompson]

yeah that makes sense - the way every / answers works is that the answers block with be run every time the function inside of every gets called. so if this yo function is what calls it, you need to call it in order to initialize your observer var

[Vivek Modi]

So i need to call yo at top of function ?