Kotlin all your tests (Mobius 2017)

fun test() Kotlin all your tests Danny Preussler Android Lead,
Google Developer Expert

@PreusslerBerlin

@PreusslerBerlin Our world so far …

@PreusslerBerlin Android Firewall by Uncalno Tekno, CC, flickr.com/photos/uncalno/8538679708

@PreusslerBerlin Watch the cool kids …

@PreusslerBerlin onika Durickova, CC, flickr.com/photos/98873911@N07/15683534672

@PreusslerBerlin But then …

@PreusslerBerlin http://davidojedalopez.com/2016/06/07/getting-started-with-kotlin-for-android-development/

@PreusslerBerlin Fly into new horizons ! (c) Sunny M5, CC
flickr.com/photos/84935187@N04/16171765851

@PreusslerBerlin Kotlin stole the best from the best

@PreusslerBerlin Kotlin stole got inspired by the best from of
the best

@PreusslerBerlin Excited by eltpics, CC flickr.com/photos/eltpics/14554630040

@PreusslerBerlin BUT

@PreusslerBerlin The Boss by Joselito TagaraoFollow, CC, flickr.com/photos/lidocaineus/7803665222/

@PreusslerBerlin “No Kotlin in production”

@PreusslerBerlin Depressed by wheatfieldbrown, CC flickr.com/photos/wheatfieldbrown/2233487982

@PreusslerBerlin But wait …

@PreusslerBerlin But wait … A backdoor

@PreusslerBerlin No one cares about your tests anyway right?

@PreusslerBerlin Tests are a safe place for experiments

@PreusslerBerlin Let’s test in Kotlin

@PreusslerBerlin Kotlin is expressive

@PreusslerBerlin @Test void testHandlesNullArguments()

@PreusslerBerlin @Test fun testHandlesNullArguments()

@PreusslerBerlin @Test fun handlesNullArguments()

@PreusslerBerlin @Test fun handles_null_arguments()

@PreusslerBerlin @Test @DisplayName("handles null arguments") fun handlesNullArguments() * Needs JUnit5

@PreusslerBerlin @Test fun ‘handles null arguments’()

@PreusslerBerlin Readability first

@PreusslerBerlin String jsonText = "{\r\n \"deal\" : {\r\n \"isTipped\" :
true,\r\n \"id\" : \"D- Company-241907\",\r\n \"areas\" : [],\r\n \"smallImageUrl\" : \"http://uat- static.groupon.de/00/00/small0000.jpg\",\r\n \"finePrint\" : \"MULTI DEAL ext Codes\",\r\n \"says\" : {\r\n \"emailContent\" : \"\",\r\n \"id\" : \"\",\r\n \"websiteContent\" : \"\",\r\n \"title\" : \"\",\r\n \"websiteContentHtml\" : \"\",\r\n \"emailContentHtml\" : \"\"\r\n },\r\n \"endAt\" : \"2014-03-31T22:59:00Z\",\r\n \"shortAnnouncementTitle\" : \"D-Company: 50% sparen in QA_AutoTestCity2\",\r\n \"placeholderUrl\" : \"http://assets2.grouponcdn.com/images/groupon/grayPlaceholder.png\",\r\n \"shippingAddressRequired\" : false,\r\n \"type\" : \"groupon\",\r\n \"isSoldOut\" : false,\r\n \"priority\" : 0,\r\n \"options\" : [\r\n {\r\n \"status\" : \"open\",\r\n \"title\" : \"MULTI DEAL ext Codes Option1\",\r\n \"isLimitedQuantity\" : false,\r\n \"tax\" : {\r\n \"amount\" : 16,\r\n \"currencyCode\" : \"EUR\",\r\n \"formattedAmount\" : \"0,16 \u20AC\"\r\n },\r\n \"minimumPurchaseQuantity\" : 1,\r\n \"expiresInDays\" : 62,\r\n \"discount\" : {\r\n \"amount\" : 100,\r\n \"currencyCode\" : \"EUR\",\r\n

@PreusslerBerlin val jsonText = """ { "channels":{ "BOOKING":1443439538, "GTG":1443439537, }
} """

@PreusslerBerlin Keep it short

@PreusslerBerlin ... Map<TYPE, Integer> signalStrength = new HashMap<>(); signalStrength.put(EDGE, 80);
signalStrength.put(WIFI to 90); ...

@PreusslerBerlin ... val signalStrength = hashMapOf(EDGE to 80, WIFI to
90) ...

@PreusslerBerlin ... tested.updateNetworkStatus(networkInfo) assertFalse(tested.isCellularConnected()) assertFalse(tested.isWifiConnected()) ...

@PreusslerBerlin ... tested.updateNetworkStatus(networkInfo) assertFalse(tested.isNotOnAnyNetwork()) ...

@PreusslerBerlin fun ConnectivityReceiver.isNotOnAnyNetwork(): Boolean { return !isCellularConnected() && !isWifiConnected()) }

@PreusslerBerlin fun ConnectivityReceiver.isNotOnAnyNetwork() = !isCellularConnected() && !isWifiConnected())

@PreusslerBerlin @Test fun `should ignore scroll if nothing moved`() {
tested.setOverScrollListener(scrollListener) tested.onScroll(START_SCROLL, START_SCROLL) verify(scrollListener, never()).onStopped() }

@PreusslerBerlin fun ScrollContainer.onScroll(started : Float, end: Float) { whenever(actionDown.action) .thenReturn(MotionEvent.ACTION_DOWN)
whenever(actionDown.y) .thenReturn(started) whenever(actionMove.action) .thenReturn(MotionEvent.ACTION_MOVE) … onTouchEventInternal(actionDown) onTouchEventInternal(actionMove) onTouchEventInternal(actionUp) }

@PreusslerBerlin @Test fun `should ignore scroll if nothing moved`() {
tested.setOverScrollListener(scrollListener) tested.onScroll(START_SCROLL, START_SCROLL) verify(scrollListener, never()).onStopped() }

@PreusslerBerlin ... tested.updateNetworkStatus(networkInfo) tested.assertNotOnAnyNetwork() ...

@PreusslerBerlin fun ConnectivityReceiver.assertNotOnAnyNetwork(){ assertFalse(isConnected()) assertFalse(isWifiConnected()) }

@PreusslerBerlin Make it consistent

@PreusslerBerlin @Test @Throws(NoSuchElementException.class) public void test() { none.get() )

@PreusslerBerlin @Test fun test() { assertFailsWith<NoSuchElementException>( none.get() )

@PreusslerBerlin What about mocks?

@PreusslerBerlin Kotlin Mockito github.com/nhaarman/mockito-kotlin

@PreusslerBerlin Syntactical Sugar around Mockito

@PreusslerBerlin val resources = mock<Resources>()

@PreusslerBerlin val resources : Resources = mock()

@PreusslerBerlin whenever(resources.getString(R.string.title) .thenReturn(”Title")

@PreusslerBerlin val resources = mock<Resources> { on { getString(R.string.title) }
doReturn ”Title” }

@PreusslerBerlin recyclerview.setAdapter(mock()) * without Java8

@PreusslerBerlin recyclerview.adapter = mock()

@PreusslerBerlin verify(recyclerview).adapter = any()

@PreusslerBerlin InOrder verifier = inOrder(parcel); verifier.verify(parcel).writeByte((byte)0); verifier.verify(parcel).writeString("path");

@PreusslerBerlin inOrder(parcel).apply { verify(parcel).writeByte(0) verify(parcel).writeString("path") }

@PreusslerBerlin ArgumentCaptor<Adapter> captor = ArgumentCaptor.forClass(Adapter.class); verify(recyclerview).setAdapter(captor.capture()); assertEquals(1, captor.getValue().getItemCount());

@PreusslerBerlin argumentCaptor<Adapter<ViewHolder>>().apply { verify(recyclerview).adapter = capture() assertEquals(1, value.itemCount) }

@PreusslerBerlin verify(recyclerView) .adapter = argForWhich { itemCount == 1 }

@PreusslerBerlin verify(parcel) .writeStringArray (argForWhich { size == 2 }) *
without Java8

@PreusslerBerlin Kluent github.com/MarkusAmshove/Kluent

@PreusslerBerlin Readability first

@PreusslerBerlin assertEquals("hello", greeting);

@PreusslerBerlin greeting shouldEqual "hello"

@PreusslerBerlin greeting `should equal` "hello"

@PreusslerBerlin list shouldContain “jon”

@PreusslerBerlin No magic here

@PreusslerBerlin infix fun <T> Array<T>.shouldContain(theThing: T)

@PreusslerBerlin list.shouldContain(“jon”)

@PreusslerBerlin list shouldContain “jon”

@PreusslerBerlin Verify on mock that mock.getPerson() was called

@PreusslerBerlin theFunction shouldThrow RuntimeException::class

@PreusslerBerlin theFunction `should throw` RuntimeException::class

@PreusslerBerlin shouldThrowTheException IllegalArgumentException::class withCause IOException::class withMessage "hello"

@PreusslerBerlin Junit5

@PreusslerBerlin Class CalculatorTest @Nested @DisplayName(”on addition") class addition { @Test
@DisplayName(”should return the sum ") fun test() {…} @Nested @DisplayName(”on substraction") class substraction{ … }

@PreusslerBerlin Spek github.com/JetBrains/spek

@PreusslerBerlin SimpleSpec: Spek({ describe("a calculator") { val calculator = SampleCalculator()
on("addition") { val sum = calculator.sum(2, 4) it("should return the sum") { assertEquals(6, sum) } } } }

on("addition") { ... } on(”substraction") { ... } } }

on("addition") { ... } on(”substraction") { ... } } describe("a broken calculator") {… }

@PreusslerBerlin describe(...) context(...) given(...) on(...) it(...)

@PreusslerBerlin Tests are a great way to learn Kotlin

@PreusslerBerlin Make a plan how to continue

@PreusslerBerlin Make a plan how to continue •tutorials

@PreusslerBerlin Make a plan how to continue •tutorials •hackathons

@PreusslerBerlin Make a plan how to continue •tutorials •hackathons •coding
Kata

@PreusslerBerlin Build an experiment, learn from it, see prove it’s
working

@PreusslerBerlin hackernoon.com/kotlin-in-production-should-you-stay-or-should-you-go-a3428b44b236

@PreusslerBerlin

fun test() Kotlin all your tests Danny Preussler @PreusslerBerlin

Kotlin all your tests (Mobius 2017)

Kotlin all your tests (Mobius 2017)

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