Use TestCoroutineScope, pass also TestCoroutineDispatcher to control execution and delay, do not skip delays with runBlockingTest{}

Kotlin/kotlinx.coroutines#1266

Author: kewiany

core/src/main/java/xyz/kewiany/contactus/core/DispatcherProvider.kt

@@ -5,12 +5,10 @@ import kotlinx.coroutines.Dispatchers
 
 
 interface DispatcherProvider {
-
     fun main(): CoroutineDispatcher = Dispatchers.Main
     fun default(): CoroutineDispatcher = Dispatchers.Default
     fun io(): CoroutineDispatcher = Dispatchers.IO
     fun unconfined(): CoroutineDispatcher = Dispatchers.Unconfined
-
 }
 
-class DefaultDispatcherProvider : DispatcherProvider
+class DefaultDispatcherProvider : DispatcherProvider

logic/src/main/java/xyz/kewiany/contactus/logic/MainLogic.kt

@@ -1,16 +1,19 @@
 package xyz.kewiany.contactus.logic
 
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.withContext
+import kotlinx.coroutines.*
 import xyz.kewiany.contactus.core.DefaultDispatcherProvider
 import xyz.kewiany.contactus.core.DispatcherProvider
 import xyz.kewiany.contactus.logic.common.MainViewState
+import kotlin.coroutines.CoroutineContext
 
-suspend fun MainViewState.MainLogic(dispatchers: DispatcherProvider = DefaultDispatcherProvider()): Boolean {
+suspend fun MainViewState.MainLogic(
+    dispatchers: DispatcherProvider = DefaultDispatcherProvider()
+): Boolean {
     commonViewState.isLoading = true
-    withContext(dispatchers.io()) {
-        delay(5000)
-        commonViewState.isLoading = false
-    }
+        withContext(dispatchers.io()) {
+            delay(1000)
+            commonViewState.isLoading = false
+        }
+
     return true
 }

logic/src/test/java/xyz/kewiany/contactus/CustomFreeSpec.kt

@@ -8,6 +8,7 @@ import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.test.TestCoroutineDispatcher
+import kotlinx.coroutines.test.TestCoroutineScope
 import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.setMain
 import org.junit.Rule
@@ -18,6 +19,7 @@ abstract class CustomFreeSpec constructor(
 ) : FreeSpec(body as FreeSpec.() -> Unit) {
 
     val testDispatcher = TestCoroutineDispatcher()
+    val testScope = TestCoroutineScope(testDispatcher)
     val testDispatcherProvider = object : DispatcherProvider {
         override fun default(): CoroutineDispatcher = testDispatcher
         override fun io(): CoroutineDispatcher = testDispatcher
@@ -35,4 +37,4 @@ abstract class CustomFreeSpec constructor(
         Dispatchers.resetMain()
         testDispatcher.cleanupTestCoroutines()
     }
-}
+}

logic/src/test/java/xyz/kewiany/contactus/MainLogicTest.kt

@@ -1,22 +1,25 @@
 package xyz.kewiany.contactus
 
 import io.kotest.matchers.shouldBe
-import kotlinx.coroutines.test.TestCoroutineScope
-import kotlinx.coroutines.test.runBlockingTest
+import kotlinx.coroutines.launch
 import xyz.kewiany.contactus.logic.MainLogic
 import xyz.kewiany.contactus.logic.common.MainViewState
 
 internal class MainLogicTest : CustomFreeSpec({
     val state = MainViewState()
     val stateT = MainStateT(state)
 
-    beforeTest {
-        testDispatcher.runBlockingTest {
+    "test loading" - {
+        testScope.launch {
             state.MainLogic(testDispatcherProvider)
         }
+        "load" {
+            stateT.state.commonViewState.isLoading shouldBe true
+        }
+        testScope.advanceTimeBy(1000)
+        "do not load" {
+            stateT.state.commonViewState.isLoading shouldBe false
+        }
     }
+})
 
-    "test" - {
-        stateT.state.commonViewState.isLoading shouldBe false
-    }
-})