CODEWITHSUNDEEP
androidtestingkotlinandroid-jetpack-compose
Sebastian Helzer
Sebastian Helzer

Reputation: 899

How to test @Model data classes from Jetpack Compose?

I'm trying to test a mapper function between my UI layer and my Domain layer.

But I get an exception thrown of java.lang.IllegalStateException: Not in a frame

This exception goes away if I change my UIModel to have a val instead of a var but then it is useless with the model updates that Jetpack Compose offers.

Is there a way to test this type of mapper?

import androidx.compose.Model
import org.junit.Assert.assertEquals
import org.junit.Test

class DataModelMapperTest {

    @Test
    fun `data model to ui model`() {
        val model = DataModel(5)
        val uiModel = UIModel(5)

        assertEquals(uiModel, model.toUIModel())
    }

    @Test
    fun `ui model to data model`() {
        val model = DataModel(5)
        val uiModel = UIModel(5)

        assertEquals(model, uiModel.toDataModel())
    }

}

@Model
data class UIModel(var value: Int)

data class DataModel(val value: Int)

fun DataModel.toUIModel(): UIModel = UIModel(this.value)

fun UIModel.toDataModel(): DataModel = DataModel(this.value)

Upvotes: 2

Views: 1075

Answers (1)

atsushieno
atsushieno

Reputation: 26

I was hitting the same issue. Here is what I figured out: I have to initialize my model objects that is annotated with @Model within (or maybe after) call to setContent().

Google's JetNews sample comes with ComposeTestRule.launchJetNewsApp() function which is called by JetnewsUiTest.setUp(). Their test class comes with full use of androidx.ui:ui-test stuff including createComposeRule(). You might want to have a look at it.

Upvotes: 1

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