Create FoldStateLoggingProvider

The aim of this class it to output fold state changes with the time between them.
Those will be logged in a follow up change to uptimize fold/unfold experience.

+ Changed files have been reformatted according to ktfmt. Those are minimal changes.
+ Making some return type explicit in dagger modules

Bug: 198305865
Test: atest FoldStateLoggingProviderTest
Change-Id: I3dcfa742f2cf3c712796b5c6f5481f319b680a12

6 files changed, 452 insertions, 49 deletions

diff --git a/packages/SystemUI/shared/src/com/android/systemui/unfold/UnfoldTransitionFactory.kt b/packages/SystemUI/shared/src/com/android/systemui/unfold/UnfoldTransitionFactory.kt
index 24e93efa09cb..953b0e018306 100644
--- a/packages/SystemUI/shared/src/com/android/systemui/unfold/UnfoldTransitionFactory.kt
+++ b/packages/SystemUI/shared/src/com/android/systemui/unfold/UnfoldTransitionFactory.kt
@@ -21,24 +21,24 @@ import android.content.Context
 import android.hardware.SensorManager
 import android.hardware.devicestate.DeviceStateManager
 import android.os.Handler
-import com.android.systemui.unfold.updates.screen.ScreenStatusProvider
 import com.android.systemui.unfold.config.ResourceUnfoldTransitionConfig
 import com.android.systemui.unfold.config.UnfoldTransitionConfig
 import com.android.systemui.unfold.progress.FixedTimingTransitionProgressProvider
 import com.android.systemui.unfold.progress.PhysicsBasedUnfoldTransitionProgressProvider
-import com.android.systemui.unfold.util.ScaleAwareTransitionProgressProvider
 import com.android.systemui.unfold.updates.DeviceFoldStateProvider
+import com.android.systemui.unfold.updates.FoldStateProvider
 import com.android.systemui.unfold.updates.hinge.EmptyHingeAngleProvider
 import com.android.systemui.unfold.updates.hinge.HingeSensorAngleProvider
+import com.android.systemui.unfold.updates.screen.ScreenStatusProvider
 import com.android.systemui.unfold.util.ATraceLoggerTransitionProgressListener
-import java.lang.IllegalStateException
+import com.android.systemui.unfold.util.ScaleAwareTransitionProgressProvider
 import java.util.concurrent.Executor
 
 /**
  * Factory for [UnfoldTransitionProgressProvider].
  *
- * This is needed as Launcher has to create the object manually.
- * Sysui create it using dagger (see [UnfoldTransitionModule]).
+ * This is needed as Launcher has to create the object manually. Sysui create it using dagger (see
+ * [UnfoldTransitionModule]).
  */
 fun createUnfoldTransitionProgressProvider(
     context: Context,
@@ -52,10 +52,45 @@ fun createUnfoldTransitionProgressProvider(
 ): UnfoldTransitionProgressProvider {
 
     if (!config.isEnabled) {
-        throw IllegalStateException("Trying to create " +
-            "UnfoldTransitionProgressProvider when the transition is disabled")
+        throw IllegalStateException(
+            "Trying to create " +
+                "UnfoldTransitionProgressProvider when the transition is disabled")
     }
 
+    val foldStateProvider =
+        createFoldStateProvider(
+            context,
+            config,
+            screenStatusProvider,
+            deviceStateManager,
+            sensorManager,
+            mainHandler,
+            mainExecutor)
+
+    val unfoldTransitionProgressProvider =
+        if (config.isHingeAngleEnabled) {
+            PhysicsBasedUnfoldTransitionProgressProvider(foldStateProvider)
+        } else {
+            FixedTimingTransitionProgressProvider(foldStateProvider)
+        }
+
+    return ScaleAwareTransitionProgressProvider(
+            unfoldTransitionProgressProvider, context.contentResolver)
+        .apply {
+            // Always present callback that logs animation beginning and end.
+            addCallback(ATraceLoggerTransitionProgressListener(tracingTagPrefix))
+        }
+}
+
+fun createFoldStateProvider(
+    context: Context,
+    config: UnfoldTransitionConfig,
+    screenStatusProvider: ScreenStatusProvider,
+    deviceStateManager: DeviceStateManager,
+    sensorManager: SensorManager,
+    mainHandler: Handler,
+    mainExecutor: Executor
+): FoldStateProvider {
     val hingeAngleProvider =
         if (config.isHingeAngleEnabled) {
             HingeSensorAngleProvider(sensorManager)
@@ -63,28 +98,13 @@ fun createUnfoldTransitionProgressProvider(
             EmptyHingeAngleProvider()
         }
 
-    val foldStateProvider = DeviceFoldStateProvider(
+    return DeviceFoldStateProvider(
         context,
         hingeAngleProvider,
         screenStatusProvider,
         deviceStateManager,
         mainExecutor,
-        mainHandler
-    )
-
-    val unfoldTransitionProgressProvider = if (config.isHingeAngleEnabled) {
-        PhysicsBasedUnfoldTransitionProgressProvider(foldStateProvider)
-    } else {
-        FixedTimingTransitionProgressProvider(foldStateProvider)
-    }
-    return ScaleAwareTransitionProgressProvider(
-        unfoldTransitionProgressProvider,
-        context.contentResolver
-    ).apply {
-        // Always present callback that logs animation beginning and end.
-        addCallback(ATraceLoggerTransitionProgressListener(tracingTagPrefix))
-    }
+        mainHandler)
 }
 
-fun createConfig(context: Context): UnfoldTransitionConfig =
-    ResourceUnfoldTransitionConfig(context)
+fun createConfig(context: Context): UnfoldTransitionConfig = ResourceUnfoldTransitionConfig(context)
diff --git a/packages/SystemUI/src/com/android/systemui/unfold/FoldStateLoggingProvider.kt b/packages/SystemUI/src/com/android/systemui/unfold/FoldStateLoggingProvider.kt
new file mode 100644
index 000000000000..1f5959e879bb
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/unfold/FoldStateLoggingProvider.kt
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.unfold
+
+import android.annotation.IntDef
+import com.android.systemui.statusbar.policy.CallbackController
+import com.android.systemui.unfold.FoldStateLoggingProvider.FoldStateLoggingListener
+import com.android.systemui.unfold.FoldStateLoggingProvider.LoggedFoldedStates
+
+/** Reports device fold states for logging purposes. */
+// TODO(b/198305865): Log state changes.
+interface FoldStateLoggingProvider : CallbackController<FoldStateLoggingListener> {
+
+    fun init()
+    fun uninit()
+
+    interface FoldStateLoggingListener {
+        fun onFoldUpdate(foldStateUpdate: FoldStateChange)
+    }
+
+    @IntDef(prefix = ["LOGGED_FOLD_STATE_"], value = [FULLY_OPENED, FULLY_CLOSED, HALF_OPENED])
+    @Retention(AnnotationRetention.SOURCE)
+    annotation class LoggedFoldedStates
+}
+
+data class FoldStateChange(
+    @LoggedFoldedStates val previous: Int,
+    @LoggedFoldedStates val current: Int,
+    val dtMillis: Long
+)
+
+const val FULLY_OPENED = 1
+const val FULLY_CLOSED = 2
+const val HALF_OPENED = 3
diff --git a/packages/SystemUI/src/com/android/systemui/unfold/FoldStateLoggingProviderImpl.kt b/packages/SystemUI/src/com/android/systemui/unfold/FoldStateLoggingProviderImpl.kt
new file mode 100644
index 000000000000..2683971f852c
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/unfold/FoldStateLoggingProviderImpl.kt
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.unfold
+
+import android.util.Log
+import com.android.systemui.unfold.FoldStateLoggingProvider.FoldStateLoggingListener
+import com.android.systemui.unfold.FoldStateLoggingProvider.LoggedFoldedStates
+import com.android.systemui.unfold.updates.FOLD_UPDATE_FINISH_CLOSED
+import com.android.systemui.unfold.updates.FOLD_UPDATE_FINISH_FULL_OPEN
+import com.android.systemui.unfold.updates.FOLD_UPDATE_FINISH_HALF_OPEN
+import com.android.systemui.unfold.updates.FOLD_UPDATE_START_CLOSING
+import com.android.systemui.unfold.updates.FOLD_UPDATE_START_OPENING
+import com.android.systemui.unfold.updates.FoldStateProvider
+import com.android.systemui.unfold.updates.FoldStateProvider.FoldUpdate
+import com.android.systemui.util.time.SystemClock
+
+/**
+ * Reports device fold states for logging purposes.
+ *
+ * Wraps the state provided by [FoldStateProvider] to output only [FULLY_OPENED], [FULLY_CLOSED] and
+ * [HALF_OPENED] for logging purposes.
+ *
+ * Note that [HALF_OPENED] state is only emitted after the device angle is stable for some timeout.
+ * Check [FoldStateProvider] impl for it.
+ *
+ * This doesn't log the following transitions:
+ * - [HALF_OPENED] -> [FULLY_OPENED]: not interesting, as there is no transition going on
+ * - [HALF_OPENED] -> [HALF_OPENED]: not meaningful.
+ */
+class FoldStateLoggingProviderImpl(
+    private val foldStateProvider: FoldStateProvider,
+    private val clock: SystemClock
+) : FoldStateLoggingProvider, FoldStateProvider.FoldUpdatesListener {
+
+    private val outputListeners: MutableList<FoldStateLoggingListener> = mutableListOf()
+
+    @LoggedFoldedStates private var lastState: Int? = null
+    private var actionStartMillis: Long? = null
+
+    override fun init() {
+        foldStateProvider.addCallback(this)
+        foldStateProvider.start()
+    }
+
+    override fun uninit() {
+        foldStateProvider.removeCallback(this)
+        foldStateProvider.stop()
+    }
+
+    override fun onHingeAngleUpdate(angle: Float) {}
+
+    override fun onFoldUpdate(@FoldUpdate update: Int) {
+        val now = clock.elapsedRealtime()
+        when (update) {
+            FOLD_UPDATE_START_OPENING -> {
+                lastState = FULLY_CLOSED
+                actionStartMillis = now
+            }
+            FOLD_UPDATE_START_CLOSING -> actionStartMillis = now
+            FOLD_UPDATE_FINISH_HALF_OPEN -> dispatchState(HALF_OPENED)
+            FOLD_UPDATE_FINISH_FULL_OPEN -> dispatchState(FULLY_OPENED)
+            FOLD_UPDATE_FINISH_CLOSED -> dispatchState(FULLY_CLOSED)
+        }
+    }
+
+    private fun dispatchState(@LoggedFoldedStates current: Int) {
+        val now = clock.elapsedRealtime()
+        val previous = lastState
+        val lastActionStart = actionStartMillis
+
+        if (previous != null && previous != current && lastActionStart != null) {
+            val time = now - lastActionStart
+            val foldStateChange = FoldStateChange(previous, current, time)
+            outputListeners.forEach { it.onFoldUpdate(foldStateChange) }
+            if (DEBUG) {
+                Log.d(TAG, "From $previous to $current in $time")
+            }
+        }
+
+        actionStartMillis = null
+        lastState = current
+    }
+
+    override fun addCallback(listener: FoldStateLoggingListener) {
+        outputListeners.add(listener)
+    }
+
+    override fun removeCallback(listener: FoldStateLoggingListener) {
+        outputListeners.remove(listener)
+    }
+}
+
+private const val DEBUG = false
+private const val TAG = "FoldStateLoggingProviderImpl"
diff --git a/packages/SystemUI/src/com/android/systemui/unfold/SysUIUnfoldModule.kt b/packages/SystemUI/src/com/android/systemui/unfold/SysUIUnfoldModule.kt
index ccde3162b177..07f9c5487c41 100644
--- a/packages/SystemUI/src/com/android/systemui/unfold/SysUIUnfoldModule.kt
+++ b/packages/SystemUI/src/com/android/systemui/unfold/SysUIUnfoldModule.kt
@@ -17,10 +17,11 @@
 package com.android.systemui.unfold
 
 import com.android.keyguard.KeyguardUnfoldTransition
-import com.android.systemui.unfold.util.NaturalRotationUnfoldProgressProvider
-import com.android.systemui.unfold.util.ScopedUnfoldTransitionProgressProvider
 import com.android.systemui.dagger.SysUISingleton
 import com.android.systemui.statusbar.phone.StatusBarMoveFromCenterAnimationController
+import com.android.systemui.unfold.util.NaturalRotationUnfoldProgressProvider
+import com.android.systemui.unfold.util.ScopedUnfoldTransitionProgressProvider
+import com.android.systemui.util.kotlin.getOrNull
 import dagger.BindsInstance
 import dagger.Module
 import dagger.Provides
@@ -36,15 +37,17 @@ annotation class SysUIUnfoldScope
 
 /**
  * Creates an injectable [SysUIUnfoldComponent] that provides objects that have been scoped with
- * [@SysUIUnfoldScope]. Since [SysUIUnfoldComponent] depends upon:
+ * [@SysUIUnfoldScope].
+ *
+ * Since [SysUIUnfoldComponent] depends upon:
  * * [Optional<UnfoldTransitionProgressProvider>]
  * * [Optional<ScopedUnfoldTransitionProgressProvider>]
  * * [Optional<NaturalRotationProgressProvider>]
+ *
  * no objects will get constructed if these parameters are empty.
  */
 @Module(subcomponents = [SysUIUnfoldComponent::class])
 class SysUIUnfoldModule {
-    constructor() {}
 
     @Provides
     @SysUISingleton
@@ -53,12 +56,16 @@ class SysUIUnfoldModule {
         rotationProvider: Optional<NaturalRotationUnfoldProgressProvider>,
         @Named(UNFOLD_STATUS_BAR) scopedProvider: Optional<ScopedUnfoldTransitionProgressProvider>,
         factory: SysUIUnfoldComponent.Factory
-    ) =
-        provider.flatMap { p1 ->
-            rotationProvider.flatMap { p2 ->
-                scopedProvider.map { p3 -> factory.create(p1, p2, p3) }
-            }
+    ): Optional<SysUIUnfoldComponent> {
+        val p1 = provider.getOrNull()
+        val p2 = rotationProvider.getOrNull()
+        val p3 = scopedProvider.getOrNull()
+        return if (p1 == null || p2 == null || p3 == null) {
+            Optional.empty()
+        } else {
+            Optional.of(factory.create(p1, p2, p3))
         }
+    }
 }
 
 @SysUIUnfoldScope
diff --git a/packages/SystemUI/src/com/android/systemui/unfold/UnfoldTransitionModule.kt b/packages/SystemUI/src/com/android/systemui/unfold/UnfoldTransitionModule.kt
index 75dfd48ad9f3..f2c156108ac6 100644
--- a/packages/SystemUI/src/com/android/systemui/unfold/UnfoldTransitionModule.kt
+++ b/packages/SystemUI/src/com/android/systemui/unfold/UnfoldTransitionModule.kt
@@ -24,8 +24,10 @@ import android.view.IWindowManager
 import com.android.systemui.dagger.qualifiers.Main
 import com.android.systemui.keyguard.LifecycleScreenStatusProvider
 import com.android.systemui.unfold.config.UnfoldTransitionConfig
+import com.android.systemui.unfold.updates.FoldStateProvider
 import com.android.systemui.unfold.util.NaturalRotationUnfoldProgressProvider
 import com.android.systemui.unfold.util.ScopedUnfoldTransitionProgressProvider
+import com.android.systemui.util.time.SystemClockImpl
 import com.android.wm.shell.unfold.ShellUnfoldProgressProvider
 import dagger.Lazy
 import dagger.Module
@@ -48,7 +50,7 @@ class UnfoldTransitionModule {
         sensorManager: SensorManager,
         @Main executor: Executor,
         @Main handler: Handler
-    ) =
+    ): Optional<UnfoldTransitionProgressProvider> =
         if (config.isEnabled) {
             Optional.of(
                 createUnfoldTransitionProgressProvider(
@@ -59,15 +61,47 @@ class UnfoldTransitionModule {
                     sensorManager,
                     handler,
                     executor,
-                    tracingTagPrefix = "systemui"
-                )
-            )
+                    tracingTagPrefix = "systemui"))
         } else {
             Optional.empty()
         }
 
     @Provides
     @Singleton
+    fun provideFoldStateProvider(
+        context: Context,
+        config: UnfoldTransitionConfig,
+        screenStatusProvider: Lazy<LifecycleScreenStatusProvider>,
+        deviceStateManager: DeviceStateManager,
+        sensorManager: SensorManager,
+        @Main executor: Executor,
+        @Main handler: Handler
+    ): Optional<FoldStateProvider> =
+        if (!config.isHingeAngleEnabled) {
+            Optional.empty()
+        } else {
+            Optional.of(
+                createFoldStateProvider(
+                    context,
+                    config,
+                    screenStatusProvider.get(),
+                    deviceStateManager,
+                    sensorManager,
+                    handler,
+                    executor))
+        }
+
+    @Provides
+    @Singleton
+    fun providesFoldStateLoggingProvider(
+        optionalFoldStateProvider: Optional<FoldStateProvider>
+    ): Optional<FoldStateLoggingProvider> =
+        optionalFoldStateProvider.map { foldStateProvider ->
+            FoldStateLoggingProviderImpl(foldStateProvider, SystemClockImpl())
+        }
+
+    @Provides
+    @Singleton
     fun provideUnfoldTransitionConfig(context: Context): UnfoldTransitionConfig =
         createConfig(context)
 
@@ -77,13 +111,9 @@ class UnfoldTransitionModule {
         context: Context,
         windowManager: IWindowManager,
         unfoldTransitionProgressProvider: Optional<UnfoldTransitionProgressProvider>
-    ) =
-        unfoldTransitionProgressProvider.map {
-            provider -> NaturalRotationUnfoldProgressProvider(
-                context,
-                windowManager,
-                provider
-            )
+    ): Optional<NaturalRotationUnfoldProgressProvider> =
+        unfoldTransitionProgressProvider.map { provider ->
+            NaturalRotationUnfoldProgressProvider(context, windowManager, provider)
         }
 
     @Provides
@@ -91,10 +121,8 @@ class UnfoldTransitionModule {
     @Singleton
     fun provideStatusBarScopedTransitionProvider(
         source: Optional<NaturalRotationUnfoldProgressProvider>
-    ) =
-        source.map {
-            provider -> ScopedUnfoldTransitionProgressProvider(provider)
-        }
+    ): Optional<ScopedUnfoldTransitionProgressProvider> =
+        source.map { provider -> ScopedUnfoldTransitionProgressProvider(provider) }
 
     @Provides
     @Singleton
diff --git a/packages/SystemUI/tests/src/com/android/systemui/unfold/FoldStateLoggingProviderTest.kt b/packages/SystemUI/tests/src/com/android/systemui/unfold/FoldStateLoggingProviderTest.kt
new file mode 100644
index 000000000000..8076b4eda883
--- /dev/null
+++ b/packages/SystemUI/tests/src/com/android/systemui/unfold/FoldStateLoggingProviderTest.kt
@@ -0,0 +1,192 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.unfold
+
+import android.testing.AndroidTestingRunner
+import androidx.test.filters.SmallTest
+import com.android.systemui.SysuiTestCase
+import com.android.systemui.unfold.FoldStateLoggingProvider.FoldStateLoggingListener
+import com.android.systemui.unfold.updates.FOLD_UPDATE_FINISH_CLOSED
+import com.android.systemui.unfold.updates.FOLD_UPDATE_FINISH_FULL_OPEN
+import com.android.systemui.unfold.updates.FOLD_UPDATE_FINISH_HALF_OPEN
+import com.android.systemui.unfold.updates.FOLD_UPDATE_START_CLOSING
+import com.android.systemui.unfold.updates.FOLD_UPDATE_START_OPENING
+import com.android.systemui.unfold.updates.FoldStateProvider
+import com.android.systemui.unfold.updates.FoldStateProvider.FoldUpdate
+import com.android.systemui.util.time.FakeSystemClock
+import com.google.common.truth.Truth.assertThat
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.ArgumentCaptor
+import org.mockito.Captor
+import org.mockito.Mock
+import org.mockito.Mockito.verify
+import org.mockito.MockitoAnnotations
+
+@RunWith(AndroidTestingRunner::class)
+@SmallTest
+class FoldStateLoggingProviderTest : SysuiTestCase() {
+
+    @Captor
+    private lateinit var foldUpdatesListener: ArgumentCaptor<FoldStateProvider.FoldUpdatesListener>
+
+    @Mock private lateinit var foldStateProvider: FoldStateProvider
+
+    private val fakeClock = FakeSystemClock()
+
+    private lateinit var foldStateLoggingProvider: FoldStateLoggingProvider
+
+    private val foldLoggingUpdates: MutableList<FoldStateChange> = arrayListOf()
+
+    private val foldStateLoggingListener =
+        object : FoldStateLoggingListener {
+            override fun onFoldUpdate(foldStateUpdate: FoldStateChange) {
+                foldLoggingUpdates.add(foldStateUpdate)
+            }
+        }
+
+    @Before
+    fun setUp() {
+        MockitoAnnotations.initMocks(this)
+
+        foldStateLoggingProvider =
+            FoldStateLoggingProviderImpl(foldStateProvider, fakeClock).apply {
+                addCallback(foldStateLoggingListener)
+                init()
+            }
+
+        verify(foldStateProvider).addCallback(foldUpdatesListener.capture())
+    }
+
+    @Test
+    fun onFoldUpdate_noPreviousOne_finishHalfOpen_nothingReported() {
+        sendFoldUpdate(FOLD_UPDATE_FINISH_HALF_OPEN)
+
+        assertThat(foldLoggingUpdates).isEmpty()
+    }
+
+    @Test
+    fun onFoldUpdate_noPreviousOne_finishFullOpen_nothingReported() {
+        sendFoldUpdate(FOLD_UPDATE_FINISH_FULL_OPEN)
+
+        assertThat(foldLoggingUpdates).isEmpty()
+    }
+
+    @Test
+    fun onFoldUpdate_noPreviousOne_finishClosed_nothingReported() {
+        sendFoldUpdate(FOLD_UPDATE_FINISH_CLOSED)
+
+        assertThat(foldLoggingUpdates).isEmpty()
+    }
+
+    @Test
+    fun onFoldUpdate_startOpening_fullOpen_changeReported() {
+        val dtTime = 10L
+
+        sendFoldUpdate(FOLD_UPDATE_START_OPENING)
+        fakeClock.advanceTime(dtTime)
+        sendFoldUpdate(FOLD_UPDATE_FINISH_FULL_OPEN)
+
+        assertThat(foldLoggingUpdates)
+            .containsExactly(FoldStateChange(FULLY_CLOSED, FULLY_OPENED, dtTime))
+    }
+
+    @Test
+    fun onFoldUpdate_startClosingThenFinishClosed_noInitialState_nothingReported() {
+        val dtTime = 10L
+
+        sendFoldUpdate(FOLD_UPDATE_START_CLOSING)
+        fakeClock.advanceTime(dtTime)
+        sendFoldUpdate(FOLD_UPDATE_FINISH_CLOSED)
+
+        assertThat(foldLoggingUpdates).isEmpty()
+    }
+
+    @Test
+    fun onFoldUpdate_startClosingThenFinishClosed_initiallyOpened_changeReported() {
+        val dtTime = 10L
+        sendFoldUpdate(FOLD_UPDATE_FINISH_FULL_OPEN)
+
+        sendFoldUpdate(FOLD_UPDATE_START_CLOSING)
+        fakeClock.advanceTime(dtTime)
+        sendFoldUpdate(FOLD_UPDATE_FINISH_CLOSED)
+
+        assertThat(foldLoggingUpdates)
+            .containsExactly(FoldStateChange(FULLY_OPENED, FULLY_CLOSED, dtTime))
+    }
+
+    @Test
+    fun onFoldUpdate_startOpeningThenHalf_initiallyClosed_changeReported() {
+        val dtTime = 10L
+        sendFoldUpdate(FOLD_UPDATE_FINISH_CLOSED)
+
+        sendFoldUpdate(FOLD_UPDATE_START_OPENING)
+        fakeClock.advanceTime(dtTime)
+        sendFoldUpdate(FOLD_UPDATE_FINISH_HALF_OPEN)
+
+        assertThat(foldLoggingUpdates)
+            .containsExactly(FoldStateChange(FULLY_CLOSED, HALF_OPENED, dtTime))
+    }
+
+    @Test
+    fun onFoldUpdate_startClosingThenHalf_initiallyOpened_changeReported() {
+        val dtTime = 10L
+        sendFoldUpdate(FOLD_UPDATE_FINISH_FULL_OPEN)
+
+        sendFoldUpdate(FOLD_UPDATE_START_CLOSING)
+        fakeClock.advanceTime(dtTime)
+        sendFoldUpdate(FOLD_UPDATE_FINISH_HALF_OPEN)
+
+        assertThat(foldLoggingUpdates)
+            .containsExactly(FoldStateChange(FULLY_OPENED, HALF_OPENED, dtTime))
+    }
+
+    @Test
+    fun onFoldUpdate_foldThenUnfold_multipleReported() {
+        val foldTime = 24L
+        val unfoldTime = 42L
+        val waitingTime = 424L
+        sendFoldUpdate(FOLD_UPDATE_FINISH_FULL_OPEN)
+
+        // Fold
+        sendFoldUpdate(FOLD_UPDATE_START_CLOSING)
+        fakeClock.advanceTime(foldTime)
+        sendFoldUpdate(FOLD_UPDATE_FINISH_CLOSED)
+        fakeClock.advanceTime(waitingTime)
+        // unfold
+        sendFoldUpdate(FOLD_UPDATE_START_OPENING)
+        fakeClock.advanceTime(unfoldTime)
+        sendFoldUpdate(FOLD_UPDATE_FINISH_FULL_OPEN)
+
+        assertThat(foldLoggingUpdates)
+            .containsExactly(
+                FoldStateChange(FULLY_OPENED, FULLY_CLOSED, foldTime),
+                FoldStateChange(FULLY_CLOSED, FULLY_OPENED, unfoldTime))
+    }
+
+    @Test
+    fun uninit_removesCallback() {
+        foldStateLoggingProvider.uninit()
+
+        verify(foldStateProvider).removeCallback(foldUpdatesListener.value)
+    }
+
+    private fun sendFoldUpdate(@FoldUpdate foldUpdate: Int) {
+        foldUpdatesListener.value.onFoldUpdate(foldUpdate)
+    }
+}