Merge pull request #13 from adidas/enhancement/add-ViewTransform

Add ViewTransform.kt + Rename TState to TView
adidas · Aug 8, 2022 · bfb9c0e · bfb9c0e
2 parents ac17cc2 + 2f4a7d7
commit bfb9c0e
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Showing 13 changed files with 86 additions and 42 deletions.
diff --git a/mvi/src/main/kotlin/com/adidas/mvi/State.kt b/mvi/src/main/kotlin/com/adidas/mvi/State.kt
@@ -2,4 +2,4 @@ package com.adidas.mvi
 
 import com.adidas.mvi.sideeffects.SideEffects
 
-public data class State<out TState, TSideEffect>(val view: TState, val sideEffects: SideEffects<TSideEffect>) : LoggableState
+public data class State<out TView, TSideEffect>(val view: TView, val sideEffects: SideEffects<TSideEffect>) : LoggableState
diff --git a/mvi/src/main/kotlin/com/adidas/mvi/reducer/ReducerExtensions.kt b/mvi/src/main/kotlin/com/adidas/mvi/reducer/ReducerExtensions.kt
@@ -26,3 +26,11 @@ public fun <TIntent : Intent, TInnerState : LoggableState, TAction> Reducer(
         defaultDispatcher = defaultDispatcher
     )
 }
+
+@Suppress("UNCHECKED_CAST")
+public inline fun <reified TView : Any> Reducer<*, *>.requireView(): TView =
+    (state.value as State<TView, *>).view.apply {
+        if (this.javaClass != TView::class.java) {
+            throw ClassCastException("Required view of ${TView::class.java} type, but found ${this.javaClass}")
+        }
+    }
diff --git a/mvi/src/main/kotlin/com/adidas/mvi/transform/SideEffectTransform.kt b/mvi/src/main/kotlin/com/adidas/mvi/transform/SideEffectTransform.kt
@@ -3,12 +3,12 @@ package com.adidas.mvi.transform
 import com.adidas.mvi.State
 import com.adidas.mvi.sideeffects.SideEffects
 
-public abstract class SideEffectTransform<TState, TSideEffect> :
-    StateTransform<State<TState, TSideEffect>> {
+public abstract class SideEffectTransform<TView, TSideEffect> :
+    StateTransform<State<TView, TSideEffect>> {
 
     protected abstract fun mutate(sideEffects: SideEffects<TSideEffect>): SideEffects<TSideEffect>
 
-    final override fun reduce(currentState: State<TState, TSideEffect>): State<TState, TSideEffect> {
+    final override fun reduce(currentState: State<TView, TSideEffect>): State<TView, TSideEffect> {
         val sideEffects = currentState.sideEffects
         return currentState.copy(sideEffects = mutate(sideEffects))
     }

diff --git a/mvi/src/main/kotlin/com/adidas/mvi/transform/StateTransform.kt b/mvi/src/main/kotlin/com/adidas/mvi/transform/StateTransform.kt
@@ -4,7 +4,10 @@ import com.adidas.mvi.Loggable
 import kotlinx.coroutines.CoroutineDispatcher
 
 public interface StateTransform<TState> : Loggable {
-    public suspend fun reduce(currentState: TState, defaultDispatcher: CoroutineDispatcher): TState {
+    public suspend fun reduce(
+        currentState: TState,
+        defaultDispatcher: CoroutineDispatcher
+    ): TState {
         return this.reduce(currentState)
     }
 

diff --git a/mvi/src/main/kotlin/com/adidas/mvi/transform/Transform.kt b/mvi/src/main/kotlin/com/adidas/mvi/transform/Transform.kt
diff --git a/mvi/src/main/kotlin/com/adidas/mvi/transform/ViewTransform.kt b/mvi/src/main/kotlin/com/adidas/mvi/transform/ViewTransform.kt
@@ -0,0 +1,12 @@
+package com.adidas.mvi.transform
+
+import com.adidas.mvi.State
+
+public abstract class ViewTransform<TView, TSideEffect> : StateTransform<State<TView, TSideEffect>> {
+
+    protected abstract fun mutate(currentState: TView): TView
+
+    final override fun reduce(currentState: State<TView, TSideEffect>): State<TView, TSideEffect> {
+        return currentState.copy(view = mutate(currentState.view))
+    }
+}
diff --git a/mvi/src/test/kotlin/com/adidas/mvi/product/FakeProductStateTransform.kt b/mvi/src/test/kotlin/com/adidas/mvi/product/FakeProductStateTransform.kt
diff --git a/mvi/src/test/kotlin/com/adidas/mvi/product/FakeProductViewTransform.kt b/mvi/src/test/kotlin/com/adidas/mvi/product/FakeProductViewTransform.kt
@@ -0,0 +1,12 @@
+package com.adidas.mvi.product
+
+import com.adidas.mvi.State
+import com.adidas.mvi.transform.ViewTransform
+
+class FakeProductViewTransform(private val state: State<ProductState, ProductSideEffect>) :
+    ViewTransform<ProductState, ProductSideEffect>() {
+
+    override fun mutate(currentState: ProductState): ProductState {
+        return state.view
+    }
+}
diff --git a/mvi/src/test/kotlin/com/adidas/mvi/reducer/ReducerTests.kt b/mvi/src/test/kotlin/com/adidas/mvi/reducer/ReducerTests.kt
@@ -2,12 +2,14 @@ package com.adidas.mvi.reducer
 
 import com.adidas.mvi.CoroutineListener
 import com.adidas.mvi.Reducer
+import com.adidas.mvi.State
 import com.adidas.mvi.TerminatedIntentException
 import com.adidas.mvi.reducer.logger.SpyLogger
 import com.adidas.mvi.reducer.logger.shouldContainFailingIntent
 import com.adidas.mvi.reducer.logger.shouldContainFailingTransform
 import com.adidas.mvi.reducer.logger.shouldContainSuccessfulIntent
 import com.adidas.mvi.reducer.logger.shouldContainSuccessfulTransform
+import com.adidas.mvi.sideeffects.SideEffects
 import com.adidas.mvi.transform.StateTransform
 import io.kotest.assertions.throwables.shouldThrow
 import io.kotest.core.spec.IsolationMode
@@ -31,40 +33,45 @@ internal class ReducerTests : BehaviorSpec({
     val coroutineListener = CoroutineListener()
     listeners(coroutineListener)
 
-    fun createReducer(executor: (intent: TestIntent) -> Flow<StateTransform<TestState>> = createIntentExecutorContainer(transform = TestTransform.Transform1)) = Reducer(
+    fun createReducer(
+        executor: (intent: TestIntent) -> Flow<StateTransform<State<TestState, TestSideEffect>>> = createIntentExecutorContainer(
+            transform = TestTransform.Transform1
+        )
+    ) = Reducer(
         coroutineScope = TestScope(coroutineListener.testCoroutineDispatcher),
-        initialState = TestState.InitialState,
+        initialState = State(TestState.InitialState, SideEffects()),
         defaultDispatcher = coroutineListener.testCoroutineDispatcher,
         logger = logger,
         intentExecutor = executor
     )
 
     Given("A reducer with a initial state") {
         val executedIntents = mutableListOf<TestIntent>()
-        val executor: (intent: TestIntent) -> Flow<StateTransform<TestState>> = createIntentExecutorContainer(executedIntents)
+        val executor: (intent: TestIntent) -> Flow<StateTransform<State<TestState, TestSideEffect>>> =
+            createIntentExecutorContainer(executedIntents)
         val reducer = createReducer(executor)
 
         When("I listen to its first value") {
             val firstValue = reducer.state.value
 
             Then("It should be the initial state") {
-                firstValue shouldBe TestState.InitialState
+                firstValue.view shouldBe TestState.InitialState
             }
         }
 
         When("I try to require a state different than the current state") {
             Then("It should cause a ClassCastException") {
                 shouldThrow<ClassCastException> {
-                    reducer.requireState<TestState.StateFromTransform1>()
+                    reducer.requireView<TestState.StateFromTransform1>()
                 }
             }
         }
 
         When("I try to require a state equal to the current state") {
-            val requiredState = reducer.requireState<TestState.InitialState>()
+            val requiredView = reducer.requireView<TestState.InitialState>()
 
             Then("It should return the cast state") {
-                requiredState shouldBe TestState.InitialState
+                requiredView shouldBe TestState.InitialState
             }
         }
 
@@ -122,7 +129,7 @@ internal class ReducerTests : BehaviorSpec({
             reducer.executeIntent(TestIntent.Transform1Producer)
 
             Then("The state should change to the state which Transform1 produces") {
-                reducer.state.value shouldBe TestState.StateFromTransform1
+                reducer.state.value.view shouldBe TestState.StateFromTransform1
                 logger.history.shouldForOne { log ->
                     log shouldContainSuccessfulTransform TestState.StateFromTransform1.toString()
                 }
@@ -138,7 +145,7 @@ internal class ReducerTests : BehaviorSpec({
             reducer.executeIntent(TestIntent.FailedTransformProducer)
 
             Then("The current state should remain the same") {
-                reducer.state.value shouldBe TestState.InitialState
+                reducer.state.value.view shouldBe TestState.InitialState
             }
 
             Then("The failure should be logged") {
@@ -163,7 +170,7 @@ internal class ReducerTests : BehaviorSpec({
             testFlow.emit(0)
 
             Then("State must have been correctly changed") {
-                reducerWrapper.state.value.shouldBe(TestState.CainState)
+                reducerWrapper.state.value.view.shouldBe(TestState.CainState)
             }
         }
 
@@ -173,30 +180,34 @@ internal class ReducerTests : BehaviorSpec({
             testFlow.emit(0)
 
             Then("Only the last intent must transform the state") {
-                reducerWrapper.state.value.shouldBe(TestState.UniqueTransformState)
+                reducerWrapper.state.value.view.shouldBe(TestState.UniqueTransformState)
             }
         }
     }
 })
 
-private fun createIntentExecutorContainer(executedIntents: MutableList<TestIntent> = mutableListOf()): (TestIntent) -> Flow<StateTransform<TestState>> =
+private fun createIntentExecutorContainer(executedIntents: MutableList<TestIntent> = mutableListOf()): (TestIntent) -> Flow<StateTransform<State<TestState, TestSideEffect>>> =
     {
         executedIntents.add(it)
         flowOf(TestTransform.Transform1)
     }
 
-private fun createIntentExecutorContainer(exception: java.lang.Exception): (TestIntent) -> Flow<StateTransform<TestState>> =
+private fun createIntentExecutorContainer(exception: java.lang.Exception): (TestIntent) -> Flow<StateTransform<State<TestState, TestSideEffect>>> =
     {
         if (it is TestIntent.SimpleIntent) throw exception
         emptyFlow()
     }
 
-private fun createIntentExecutorContainer(intent: TestIntent = TestIntent.FailedTransformProducer, transform: TestTransform): (TestIntent) -> Flow<StateTransform<TestState>> =
+private fun createIntentExecutorContainer(
+    intent: TestIntent = TestIntent.FailedTransformProducer,
+    transform: TestTransform
+): (TestIntent) -> Flow<StateTransform<State<TestState, TestSideEffect>>> =
     {
         when (it) {
             intent -> {
                 flowOf(transform)
             }
+
             else -> emptyFlow()
         }
     }
diff --git a/mvi/src/test/kotlin/com/adidas/mvi/reducer/TestCancellationReducerWrapper.kt b/mvi/src/test/kotlin/com/adidas/mvi/reducer/TestCancellationReducerWrapper.kt
@@ -2,7 +2,9 @@ package com.adidas.mvi.reducer
 
 import com.adidas.mvi.CoroutineListener
 import com.adidas.mvi.Reducer
+import com.adidas.mvi.State
 import com.adidas.mvi.reducer.logger.SpyLogger
+import com.adidas.mvi.sideeffects.SideEffects
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.emptyFlow
 import kotlinx.coroutines.flow.flowOf
@@ -17,7 +19,7 @@ internal class TestCancellationReducerWrapper(
 
     private val reducer = Reducer(
         coroutineScope = TestScope(coroutineListener.testCoroutineDispatcher),
-        initialState = TestState.InitialState,
+        initialState = State(TestState.InitialState, SideEffects()),
         defaultDispatcher = coroutineListener.testCoroutineDispatcher,
         logger = SpyLogger(),
         intentExecutor = this::executeIntent
@@ -33,7 +35,12 @@ internal class TestCancellationReducerWrapper(
     ): Flow<TestTransform> {
         return when (intent) {
             TestIntent.AbelIntent -> someTestFlow.map { TestTransform.AbelTransform }
-            TestIntent.CainIntent -> flowOf(TestTransform.CainTransform).onStart { reducer.cleanIntentJobsOfType(TestIntent.AbelIntent::class) }
+            TestIntent.CainIntent -> flowOf(TestTransform.CainTransform).onStart {
+                reducer.cleanIntentJobsOfType(
+                    TestIntent.AbelIntent::class
+                )
+            }
+
             is TestIntent.UniqueTransformIntent -> someTestFlow.map { TestTransform.UniqueTransform(intent.id) }
             else -> emptyFlow()
         }

diff --git a/mvi/src/test/kotlin/com/adidas/mvi/reducer/TestSideEffect.kt b/mvi/src/test/kotlin/com/adidas/mvi/reducer/TestSideEffect.kt
@@ -0,0 +1,3 @@
+package com.adidas.mvi.reducer
+
+class TestSideEffect
diff --git a/mvi/src/test/kotlin/com/adidas/mvi/reducer/TestTransform.kt b/mvi/src/test/kotlin/com/adidas/mvi/reducer/TestTransform.kt
@@ -1,37 +1,37 @@
 package com.adidas.mvi.reducer
 
-import com.adidas.mvi.transform.StateTransform
+import com.adidas.mvi.transform.ViewTransform
 
 internal const val IMPOSSIBLE_INTENT_ID = 1
 internal const val UNIQUE_INTENT_ID = 2
 
-internal sealed class TestTransform : StateTransform<TestState> {
+internal sealed class TestTransform : ViewTransform<TestState, TestSideEffect>() {
     object Transform1 : TestTransform() {
-        override fun reduce(currentState: TestState): TestState {
+        override fun mutate(currentState: TestState): TestState {
             return TestState.StateFromTransform1
         }
     }
 
     object FailedTransform : TestTransform() {
-        override fun reduce(currentState: TestState): TestState {
+        override fun mutate(currentState: TestState): TestState {
             throw Exception()
         }
     }
 
     object AbelTransform : TestTransform() {
-        override fun reduce(currentState: TestState): TestState {
+        override fun mutate(currentState: TestState): TestState {
             return TestState.AbelState
         }
     }
 
     object CainTransform : TestTransform() {
-        override fun reduce(currentState: TestState): TestState {
+        override fun mutate(currentState: TestState): TestState {
             return TestState.CainState
         }
     }
 
     data class UniqueTransform(val id: Int) : TestTransform() {
-        override fun reduce(currentState: TestState): TestState {
+        override fun mutate(currentState: TestState): TestState {
             return when (id) {
                 IMPOSSIBLE_INTENT_ID -> TestState.ImpossibleState
                 UNIQUE_INTENT_ID -> TestState.UniqueTransformState

diff --git a/mvi/src/test/kotlin/com/adidas/mvi/transform/StateTransformTest.kt b/mvi/src/test/kotlin/com/adidas/mvi/transform/StateTransformTest.kt
@@ -1,7 +1,7 @@
 package com.adidas.mvi.transform
 
 import com.adidas.mvi.State
-import com.adidas.mvi.product.FakeProductStateTransform
+import com.adidas.mvi.product.FakeProductViewTransform
 import com.adidas.mvi.product.ProductSideEffect
 import com.adidas.mvi.product.ProductState
 import com.adidas.mvi.sideeffects.SideEffects
@@ -15,7 +15,7 @@ class StateTransformTest : ShouldSpec({
 
         should("use mutate() function for reducing state") {
             val state = State(ProductState.Loading, SideEffects<ProductSideEffect>())
-            FakeProductStateTransform(state).reduce(state.view) shouldBe state.view
+            FakeProductViewTransform(state).reduce(state).view shouldBe state.view
         }
     }
 })