Automated Testing in a KMM Project

Why and how to write unit tests in a KMM project.

Transcript

1. ©2021 Wantedly, Inc.
   Automated Testing
   in a KMM Project
   KMM勉強会
   Apr 6, 2021 - Malvin Sutanto
   

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2. ©2021 Wantedly, Inc.
   Introduction
   

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3. ©2021 Wantedly, Inc.
   Introduction
   Malvin Sutanto
   Software Engineer - Android
   Twitter/ Medium: @malvinsutanto
   

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4. ©2021 Wantedly, Inc.
   1. Testing in a KMM project
   2. Writing Tests
   3. Running KMM Tests
   4. 3rd Party Libraries for Writing Tests
   5. Issues with Testing in a KMM Project
   Agenda
   

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5. ©2021 Wantedly, Inc.
   Testing in a KMM project
   

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6. ©2021 Wantedly, Inc.
   KMM Structure
   6*
   'SBNFXPSL
   6*
   ""3
   DPNNPO.BJO
   J04.BJO BOESPJE.BJO
   

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7. ©2021 Wantedly, Inc.
   KMM Structure
   6*
   'SBNFXPSL
   6*
   ""3
   DPNNPO.BJO
   J04.BJO BOESPJE.BJO
   Manual test
   

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8. ©2021 Wantedly, Inc.
   KMM Structure
   6*
   'SBNFXPSL
   6*
   ""3
   DPNNPO.BJO
   J04.BJO BOESPJE.BJO
   Manual test
   Bottleneck
   

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9. ©2021 Wantedly, Inc.
   KMM Structure
   6*
   'SBNFXPSL
   6*
   ""3
   DPNNPO.BJO
   J04.BJO BOESPJE.BJO
   Automated test
   Bottleneck
   

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10. ©2021 Wantedly, Inc.
    KMM Structure
    6*
    'SBNFXPSL
    6*
    ""3
    DPNNPO.BJO
    J04.BJO BOESPJE.BJO
    Flaky
    Bottleneck
    

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11. ©2021 Wantedly, Inc.
    KMM Structure
    6*
    'SBNFXPSL
    6*
    ""3
    DPNNPO.BJO
    J04.BJO BOESPJE.BJO
    Automated test
    

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12. ©2021 Wantedly, Inc.
    Writing Tests
    

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13. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    DPNNPO5FTU
    J045FTU
    BOESPJE5FTU
    Tests that will be run on both iOS and Android platform
    Tests that will be run only on iOS platform
    Tests that will be run only on Android platform
    

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14. ©2021 Wantedly, Inc.
    Sample Implementation
    https://github.com/touchlab/KaMPKit
    Page Title Page Subtitle
    

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15. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    DPNNPO5FTU
    // kmm-module/build.gradle.kts
    kotlin {
    ...
    sourceSets {
    ...
    val commonTest by getting {
    dependencies {
    implementation(kotlin("test-common"))
    implementation(kotlin("test-annotations-common"))
    }
    }
    }
    }
    

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16. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    DPNNPO5FTU
    // kmm-module/src/commonTest/kotlin/BaseTest.kt
    import kotlinx.coroutines.CoroutineScope
    expect abstract class BaseTest() {
    fun runTest(block: suspend CoroutineScope.() -> Unit)
    }
    

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17. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    DPNNPO5FTU
    // kmm-module/src/commonTest/kotlin/BaseTest.kt
    import kotlinx.coroutines.CoroutineScope
    expect abstract class BaseTest() {
    fun runTest(block: suspend CoroutineScope.() -> Unit)
    }
    

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18. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    BOESPJE5FTU
    // kmm-module/build.gradle.kts
    kotlin {
    ...
    sourceSets {
    ...
    val androidTest by getting {
    dependencies {
    implementation(kotlin("test-junit"))
    implementation("junit:junit:4.13")
    implementation("androidx.test:core:1.3.0")
    implementation("androidx.test:runner:1.3.0")
    implementation("androidx.test:rules:1.3.0")
    implementation("androidx.test.ext:junit-ktx:1.1.2")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3")
    implementation("org.robolectric:robolectric:4.4")
    }
    }
    }
    }
    

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19. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    BOESPJE5FTU
    // kmm-module/build.gradle.kts
    kotlin {
    ...
    sourceSets {
    ...
    val androidTest by getting {
    dependencies {
    implementation(kotlin("test-junit"))
    implementation("junit:junit:4.13")
    implementation("androidx.test:core:1.3.0")
    implementation("androidx.test:runner:1.3.0")
    implementation("androidx.test:rules:1.3.0")
    implementation("androidx.test.ext:junit-ktx:1.1.2")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3")
    implementation("org.robolectric:robolectric:4.4")
    }
    }
    }
    }
    

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20. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    BOESPJE5FTU
    // kmm-module/build.gradle.kts
    kotlin {
    ...
    sourceSets {
    ...
    val androidTest by getting {
    dependencies {
    implementation(kotlin("test-junit"))
    implementation("junit:junit:4.13")
    implementation("androidx.test:core:1.3.0")
    implementation("androidx.test:runner:1.3.0")
    implementation("androidx.test:rules:1.3.0")
    implementation("androidx.test.ext:junit-ktx:1.1.2")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3")
    implementation("org.robolectric:robolectric:4.4")
    }
    }
    }
    }
    

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21. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    BOESPJE5FTU
    // kmm-module/src/androidTest/kotlin/BaseTest.kt
    @RunWith(AndroidJUnit4::class)
    @Config(sdk = [30])
    actual abstract class BaseTest {
    @get:Rule
    val coroutineTestRule = CoroutineTestRule()
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    runBlocking { block() }
    }
    }
    

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22. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    BOESPJE5FTU
    // kmm-module/src/androidTest/kotlin/BaseTest.kt
    @RunWith(AndroidJUnit4::class)
    @Config(sdk = [30])
    actual abstract class BaseTest {
    @get:Rule
    val coroutineTestRule = CoroutineTestRule()
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    runBlocking { block() }
    }
    }
    

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23. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    BOESPJE5FTU
    // kmm-module/src/androidTest/kotlin/BaseTest.kt
    @RunWith(AndroidJUnit4::class)
    @Config(sdk = [30])
    actual abstract class BaseTest {
    @get:Rule
    val coroutineTestRule = CoroutineTestRule()
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    runBlocking { block() }
    }
    }
    

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24. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    BOESPJE5FTU
    // kmm-module/src/androidTest/kotlin/BaseTest.kt
    @RunWith(AndroidJUnit4::class)
    @Config(sdk = [30])
    actual abstract class BaseTest {
    @get:Rule
    val coroutineTestRule = CoroutineTestRule()
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    runBlocking { block() }
    }
    }
    

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25. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    BOESPJE5FTU
    // kmm-module/src/androidTest/kotlin/BaseTest.kt
    class CoroutineTestRule(
    private val testDispatcher: CoroutineDispatcher = Executors.newSingleThreadExecutor()
    .asCoroutineDispatcher()
    ) : TestWatcher() {
    override fun starting(description: Description?) {
    super.starting(description)
    Dispatchers.setMain(testDispatcher)
    }
    override fun finished(description: Description?) {
    super.finished(description)
    Dispatchers.resetMain()
    }
    }
    

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26. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    BOESPJE5FTU
    // kmm-module/src/androidTest/kotlin/BaseTest.kt
    class CoroutineTestRule(
    private val testDispatcher: CoroutineDispatcher = Executors.newSingleThreadExecutor()
    .asCoroutineDispatcher()
    ) : TestWatcher() {
    override fun starting(description: Description?) {
    super.starting(description)
    Dispatchers.setMain(testDispatcher)
    }
    override fun finished(description: Description?) {
    super.finished(description)
    Dispatchers.resetMain()
    }
    }
    

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27. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    JPT5FTU
    // kmm-module/src/iosTest/kotlin/BaseTest.kt
    actual abstract class BaseTest {
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    var error: Throwable? = null
    GlobalScope.launch(Dispatchers.Main) {
    try {
    block()
    } catch (t: Throwable) {
    error = t
    } finally {
    CFRunLoopStop(CFRunLoopGetCurrent())
    }
    }
    CFRunLoopRun()
    error?.also { throw it }
    }
    }
    

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28. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    JPT5FTU
    // kmm-module/src/iosTest/kotlin/BaseTest.kt
    actual abstract class BaseTest {
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    var error: Throwable? = null
    GlobalScope.launch(Dispatchers.Main) {
    try {
    block()
    } catch (t: Throwable) {
    error = t
    } finally {
    CFRunLoopStop(CFRunLoopGetCurrent())
    }
    }
    CFRunLoopRun()
    error?.also { throw it }
    }
    }
    

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29. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    JPT5FTU
    // kmm-module/src/iosTest/kotlin/BaseTest.kt
    actual abstract class BaseTest {
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    var error: Throwable? = null
    GlobalScope.launch(Dispatchers.Main) {
    try {
    block()
    } catch (t: Throwable) {
    error = t
    } finally {
    CFRunLoopStop(CFRunLoopGetCurrent())
    }
    }
    CFRunLoopRun()
    error?.also { throw it }
    }
    }
    

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30. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    JPT5FTU
    // kmm-module/src/iosTest/kotlin/BaseTest.kt
    actual abstract class BaseTest {
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    var error: Throwable? = null
    GlobalScope.launch(Dispatchers.Main) {
    try {
    block()
    } catch (t: Throwable) {
    error = t
    } finally {
    CFRunLoopStop(CFRunLoopGetCurrent())
    }
    }
    CFRunLoopRun()
    error?.also { throw it }
    }
    }
    

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31. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    JPT5FTU
    // kmm-module/src/iosTest/kotlin/BaseTest.kt
    actual abstract class BaseTest {
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    var error: Throwable? = null
    GlobalScope.launch(Dispatchers.Main) {
    try {
    block()
    } catch (t: Throwable) {
    error = t
    } finally {
    CFRunLoopStop(CFRunLoopGetCurrent())
    }
    }
    CFRunLoopRun()
    error?.also { throw it }
    }
    }
    

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32. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    JPT5FTU
    // kmm-module/src/iosTest/kotlin/BaseTest.kt
    actual abstract class BaseTest {
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    var error: Throwable? = null
    GlobalScope.launch(Dispatchers.Main) {
    try {
    block()
    } catch (t: Throwable) {
    error = t
    } finally {
    CFRunLoopStop(CFRunLoopGetCurrent())
    }
    }
    CFRunLoopRun()
    error?.also { throw it }
    }
    }
    

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33. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    JPT5FTU
    // kmm-module/src/iosTest/kotlin/BaseTest.kt
    actual abstract class BaseTest {
    actual fun runTest(block: suspend CoroutineScope.() -> Unit) {
    var error: Throwable? = null
    GlobalScope.launch(Dispatchers.Main) {
    try {
    block()
    } catch (t: Throwable) {
    error = t
    } finally {
    CFRunLoopStop(CFRunLoopGetCurrent())
    }
    }
    CFRunLoopRun()
    error?.also { throw it }
    }
    }
    

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34. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    DPNNPO5FTU
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my simple test`() {
    assertEquals(2, 1 + 1)
    }
    @Test
    fun `my coroutines test`() = runTest {
    assertEquals(2, mySum(1, 1))
    }
    private suspend fun mySum(a: Int, b: Int): Int {
    delay(200)
    return a + b
    }
    }
    

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35. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    DPNNPO5FTU
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my simple test`() {
    assertEquals(2, 1 + 1)
    }
    @Test
    fun `my coroutines test`() = runTest {
    assertEquals(2, mySum(1, 1))
    }
    private suspend fun mySum(a: Int, b: Int): Int {
    delay(200)
    return a + b
    }
    }
    

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36. ©2021 Wantedly, Inc.
    KMM Module Test Folder Structure
    DPNNPO5FTU
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my simple test`() {
    assertEquals(2, 1 + 1)
    }
    @Test
    fun `my coroutines test`() = runTest {
    assertEquals(2, mySum(1, 1))
    }
    private suspend fun mySum(a: Int, b: Int): Int {
    delay(200)
    return a + b
    }
    }
    

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37. ©2021 Wantedly, Inc.
    Running Tests
    

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38. ©2021 Wantedly, Inc.
    $ gradlew :kmm-module:test
    $ gradlew :kmm-module:testDebugUnitTest
    $ gradlew :kmm-module:testReleaseUnitTest
    $ gradlew :kmm-module:iosTestX64Test
    Running Tests
    Intellij IDE Gradle Command
    

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39. ©2021 Wantedly, Inc.
    $ gradlew :kmm-module:test
    $ gradlew :kmm-module:testDebugUnitTest
    $ gradlew :kmm-module:testReleaseUnitTest
    $ gradlew :kmm-module:iosTestX64Test
    Running Tests
    Intellij IDE Gradle Command
    Android: commonTest + androidTest
    

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40. ©2021 Wantedly, Inc.
    $ gradlew :kmm-module:test
    $ gradlew :kmm-module:testDebugUnitTest
    $ gradlew :kmm-module:testReleaseUnitTest
    $ gradlew :kmm-module:iosTestX64Test
    Running Tests
    Intellij IDE Gradle Command
    iOS: commonTest + iOSTest
    

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41. ©2021 Wantedly, Inc.
    $ gradlew :kmm-module:test
    $ gradlew :kmm-module:testDebugUnitTest
    $ gradlew :kmm-module:testReleaseUnitTest
    $ gradlew :kmm-module:iosTestX64Test
    Running Tests
    Intellij IDE Gradle Command
    All platforms: commonTest + iOSTest + androidTest
    

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42. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing
    

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43. ©2021 Wantedly, Inc.
    Kotest
    https://kotest.io
    Multiplatform test framework, assertion libraries, and property test library for Kotlin.
    3rd Party Libraries for Testing Kotest
    4USVDUVSFZPVSUFTUXJUI
    #FIBWJPS4QFD
    4FUPGNBUDIFSTUP
    WBMJEBUFUFTUT
    7BMVFHFOFSBUPSTGPS
    UFTUJOHFEHFDBTFTBOE
    SBOEPNWBMVFT
    

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44. ©2021 Wantedly, Inc.
    Kotest
    https://kotest.io
    Multiplatform test framework, assertion libraries, and property test library for Kotlin.
    3rd Party Libraries for Testing Kotest
    4USVDUVSFZPVSUFTUXJUI
    #FIBWJPS4QFD
    4FUPGNBUDIFSTUP
    WBMJEBUFUFTUT
    7BMVFHFOFSBUPSTGPS
    UFTUJOHFEHFDBTFTBOE
    SBOEPNWBMVFT
    

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45. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Kotest - assertions library
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my simple test`() {
    assertEquals(2, 1 + 1)
    }
    @Test
    fun `my coroutines test`() = runTest {
    assertEquals(2, mySum(1, 1))
    }
    private suspend fun mySum(a: Int, b: Int): Int {
    delay(200)
    return a + b
    }
    }
    

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46. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Kotest - assertions library
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my simple test`() {
    1 + 1 shouldBe 2
    }
    @Test
    fun `my coroutines test`() = runTest {
    assertEquals(2, mySum(1, 1))
    }
    private suspend fun mySum(a: Int, b: Int): Int {
    delay(200)
    return a + b
    }
    }
    

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47. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Kotest - assertions library
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my simple test`() {
    1 + 1 shouldBe 2
    }
    @Test
    fun `my coroutines test`() = runTest {
    assertEquals(2, mySum(1, 1))
    }
    private suspend fun mySum(a: Int, b: Int): Int {
    delay(200)
    return a + b
    }
    }
    

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48. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Kotest - assertions library
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my simple test`() {
    1 + 1 shouldBe 2
    }
    @Test
    fun `my coroutines test`() = runTest {
    mySum(1, 1) shouldBe 2
    }
    private suspend fun mySum(a: Int, b: Int): Int {
    delay(200)
    return a + b
    }
    }
    

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49. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Kotest - assertions library
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my simple test`() {
    1 + 1 shouldBe 2
    }
    @Test
    fun `my coroutines test`() = runTest {
    mySum(1, 1) shouldBe 2
    }
    private suspend fun mySum(a: Int, b: Int): Int {
    delay(200)
    return a + b
    }
    }
    assertEquals(2, 1 + 1)
    assertEquals(2, mySum(1, 1))
    

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50. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Kotest - property test library
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my coroutines test`() = runTest {
    mySum(1, 1) shouldBe 2
    }
    }
    mySum(-2, -3)
    mySum(2, -3)
    mySum(-2, 3)
    mySum(2, 0)
    ...
    

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51. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Kotest - property test library
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my coroutines test`() = runTest {
    checkAll(
    config = PropTestConfig(seed = 211125L),
    genA = Arb.int(-25..25),
    genB = Arb.int(-25..25),
    iterations = 100
    ) { a, b ->
    mySum(a, b) shouldBe (a + b)
    }
    }
    }
    

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52. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Kotest - property test library
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my coroutines test`() = runTest {
    checkAll(
    config = PropTestConfig(seed = 211125L),
    genA = Arb.int(-25..25),
    genB = Arb.int(-25..25),
    iterations = 100
    ) { a, b ->
    mySum(a, b) shouldBe (a + b)
    }
    }
    }
    Generate random values from -25 to 25
    

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53. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Kotest - property test library
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my coroutines test`() = runTest {
    checkAll(
    config = PropTestConfig(seed = 211125L),
    genA = Arb.int(-25..25),
    genB = Arb.int(-25..25),
    iterations = 100
    ) { a, b ->
    mySum(a, b) shouldBe (a + b)
    }
    }
    }
    Repeat 100 times
    

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54. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Kotest - property test library
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun `my coroutines test`() = runTest {
    checkAll(
    config = PropTestConfig(seed = 211125L),
    genA = Arb.int(-25..25),
    genB = Arb.int(-25..25),
    iterations = 100
    ) { a, b ->
    mySum(a, b) shouldBe (a + b)
    }
    }
    }
    

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55. ©2021 Wantedly, Inc.
    Turbine
    https://github.com/cashapp/turbine
    A small testing library to test kotlinx.coroutines Flow
    3rd Party Libraries for Testing Turbine
    

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56. ©2021 Wantedly, Inc.
    3rd Party Libraries for Testing Turbine
    // kmm-module/src/commonTest/kotlin/MyTest.kt
    class MyTest : BaseTest() {
    @Test
    fun myFlowTest() = runTest {
    flowOf("one", "two").test {
    expectItem() shouldBe "one"
    expectItem() shouldBe "two"
    expectComplete()
    }
    }
    }
    expectError()
    expectEvent()
    expectNoEvents()
    cancel()
    cancelAndIgnoreRemainingEvents()
    

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57. ©2021 Wantedly, Inc.
    Issues with Testing in a KMM Project
    

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58. ©2021 Wantedly, Inc.
    1. Test Doubles (Fakes, Mocks, etc)
    • MockK does not yet support Kotlin/Native
    2. Testing with Coroutines
    • kotlinx-coroutines-test only supports Kotlin/JVM for now
    3. Code coverage
    • Currently impossible to measure
    4. Integration and E2E tests
    • Creates Fake implementation whose behavior can be overridden
    Issues with Testing in a KMM Project
    

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59. ©2021 Wantedly, Inc.
    Summary
    

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60. ©2021 Wantedly, Inc.
    1. Manual UI testing with a KMM project is
    difficult
    2. Write automated test to ensure Business
    Logic is implemented correctly
    3. Use 3rd party libraries to help write unit tests
    Summary
    

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61. ©2021 Wantedly, Inc.
    Thank You!
    @MalvinSutanto
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