Transforming your Tests with Kotlin

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Transforming Your Tests With Kotlin Victoria Gonda victoriagonda.com @TTGonda

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Testing with Kotlin

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https://twitter.com/TTGonda/status/1123025116139544576

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Victoria Gonda • Android Engineer at Buffer • Author and Editor at RayWenderlich.com • Hedgehog and cat owner • she/her

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Kotlin features

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`Backticks`

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https://twitter.com/skentphd/status/1123035724788453377 https://twitter.com/jshvarts/status/1123362376840040448

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Without `Backticks` @Test fun whenDeleteIsCalled_onlyCorrespondingDataIsDeleted() { }

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`Backticks` @Test fun `deleteUpdates only deletes corresponding data`() { }

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`Backticks` java.lang.AssertionError: Assertion failed at package.Test.deleteUpdates only deletes corresponding data

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Higher order functions

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https://twitter.com/wakingrufus/status/ 1123053243800653825 https://twitter.com/RBusarow/status/ 1123057633261441024 https://twitter.com/jessewilson/status/ 1123055645824028672

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Higher order functions fun verifyLinkOpen(expectedUrl: String, openLink: () -> Unit) { Intents.init() try { openLink() intended(allOf(hasAction(ACTION_VIEW), hasData(expectedUrl))) } finally { Intents.release() } }

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Higher order functions verifyLinkOpen("https://buffer.com") { clickBufferButton() }

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Screen Robots

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Screen Robots class CalculatorScreenRobot : ScreenRobot() { fun verifyTipIsCorrect(tip: String): CalculatorScreenRobot { return checkViewHasText(R.id.textTip, tip) } fun inputCheckAmountAndSelectOkayButton(input: String): CalculatorScreenRobot { return enterTextIntoView(R.id.inputAmount, input) .clickOkOnView(R.id.buttonOkay) } }

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Screen Robots withRobot(CalculatorScreenRobot::class.java) .inputCheckAmountAndSelectOkayButton("11") .verifyTipIsCorrect("1.98")

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Screen Robots robot { inputCheckAmountAndSelectOkayButton("11") verifyTipIsCorrect("1.98") }

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Extension functions

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https://twitter.com/objcode/status/1123082385090908160

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Without Extension functions assert(contentViewModel.observeQueueState().value == ContentState.Loading())

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Extension functions private fun ContentViewModel.hasState(state: ContentState) { assert(observeQueueState().value == state) }

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Extension functions contentViewModel.hasState(ContentState.Loading())

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Infix functions

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https://twitter.com/PreusslerBerlin/status/ 1123107023103696896 https://twitter.com/jossiwolf/status/ 1123039773541707776

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Without Infix functions fun verifyTipIsCorrect(tip: String) { onView(withId(R.id.textTip)) .check(matches(withText(tip))) }

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Infix functions infix fun Int.shouldHaveText(expected: String) { onView(withId(this)) .check(matches(withText(expected))) }

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Infix functions fun verifyTipIsCorrect(tip: String) { R.id.textTip shouldHaveText tip }

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Combining multiple features inline fun > robot(block: T.() -> Unit) { T::class.java.newInstance().block() } robot { inputCheckAmountAndSelectOkayButton("11") verifyTipIsCorrect("1.98") }

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Data classes

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https://twitter.com/shekibobo/status/ 1123037412328988673 https://twitter.com/tasomaniac/status/ 1123104225196683264

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Data classes data class UpdateData( var shareMode: ShareMode = ShareMode.ADD_TO_QUEUE, var media: MediaEntity? = null, var extraMedia: Array? = null, var retweet: RetweetEntity? = null, @Nullable var scheduledAt: Long? = null, var text: String = "", var facebookText: String = "", var profileIds: List? = null, var subProfileIds: List? = null, var sourceUrl: String? = null, var importId: String? = null, var shareDetails: ShareDetails? = null, var userChangedMedia: Boolean = false, var isEditing: Boolean = false, var editingProfile: ProfileEntity? = null, var networks: List? = null, var facebookTags: List? = null, var id: String? = "", var lastEditedDate: Long? = 0, var editingProfileTimezone: String? = null, val location: Location? = null, val commentEnabled: Boolean = false, val commentText: String? = null )

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Data classes UpdateData(null, null, emptyArray(), null, 0, "Hello World", "", emptyList(), emptyList(), null, "buffer.com", null, false, true, null, emptyList(), null, "", 0, null, null, false, "")

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Data classes UpdateData(text = "Hello World", sourceUrl = "buffer.com")

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Lazy property delegation

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https://twitter.com/POTUS404/status/1123210124108103680

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private val errorMessage by lazy { DataFactory.randomString() }

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Example https://youtu.be/wlb3lg5JocA

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Example https://youtu.be/wlb3lg5JocA

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Kotlin libraries

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Kakao

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https://twitter.com/erafn/status/1123067587125026816

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Kakao class SearchScreen : Screen() { val searchButton = KButton { withId(R.id.searchButton) } val snackbar = KView { withId(com.google.android.material.R.id.snackbar_text) } }

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Kakao screen { searchButton.click() snackbar.isDisplayed() }

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Spek

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Spek class ProfileSpec : Spek({ given("twitter profile") { on("validate image count") { it("should be valid for four images") { } it("should fail for ten images") { } } } })

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Spek Spek:ProfileSpec:given twitter profile:on validate image count:it   should be valid for four images  => java.lang.AssertionError: Expected , actual .

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Mockito-Kotlin

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https://twitter.com/Exallium/status/1123214566052323329

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Mockito val mockedUpdate = mock(Update::class.java) `when`(mockedUpdate.toString()).thenReturn("Update")

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Mockito-Kotlin val mockedUpdate = mock { on { toString() } doReturn "Update" }

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Kluent

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Kluent message shouldEqual "hello" message.shouldEqual("hello") message `should equal` "hello"

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Kluent invoking { read() } shouldThrow IOException::class

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Kluent Verify on mockedUpdate that mockedUpdate.toString() was called When calling stub.length itReturns 4

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Biscotti

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Biscotti verifyActivityLaunched(MainActivity::class.java.name) { onView(withId(R.id.button_faq)) .perform(click()) }