add simple test for car app

app/build.gradle

@@ -94,6 +94,10 @@ android {
         disable 'NullSafeMutableLiveData'
     }
 
+    testOptions {
+        unitTests.includeAndroidResources true
+    }
+
     // add API keys from environment variable if not set in apikeys.xml
     applicationVariants.all { variant ->
         ext.env = System.getenv()
@@ -170,9 +174,10 @@ dependencies {
     implementation 'com.github.romandanylyk:PageIndicatorView:b1bad589b5'
 
     // Android Auto
-    googleImplementation 'androidx.car.app:app:1.2.0-rc01'
-    googleNormalImplementation 'androidx.car.app:app-projected:1.2.0-rc01'
-    googleAutomotiveImplementation 'androidx.car.app:app-automotive:1.2.0-rc01'
+    def carAppVersion = '1.2.0-rc01'
+    googleImplementation "androidx.car.app:app:$carAppVersion"
+    googleNormalImplementation "androidx.car.app:app-projected:$carAppVersion"
+    googleAutomotiveImplementation "androidx.car.app:app-automotive:$carAppVersion"
 
     // AnyMaps
     def anyMapsVersion = '3c67d7a1dc'
@@ -220,10 +225,18 @@ dependencies {
     // debug tools
     implementation 'com.facebook.stetho:stetho:1.5.1'
     implementation 'com.facebook.stetho:stetho-okhttp3:1.5.1'
+
+    // testing
     testImplementation 'junit:junit:4.13.2'
     testImplementation "com.squareup.okhttp3:mockwebserver:4.9.0"
     //noinspection GradleDependency
     testImplementation 'org.json:json:20080701'
+
+    // testing for car app
+    testGoogleImplementation "androidx.car.app:app-testing:$carAppVersion"
+    testGoogleImplementation 'org.robolectric:robolectric:4.7.3'
+    testGoogleImplementation 'androidx.test:core:1.4.0'
+
     androidTestImplementation 'androidx.test.ext:junit:1.1.3'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
 

app/src/google/java/net/vonforst/evmap/auto/MapScreen.kt

@@ -82,7 +82,9 @@ class MapScreen(ctx: CarContext, val session: EVMapSession) :
         Transformations.map(referenceData) { api.getFilters(it, carContext.stringProvider()) }
     private val filtersWithValue = filtersWithValue(filters, filterValues)
 
-    private val hardwareMan = ctx.getCarService(CarContext.HARDWARE_SERVICE) as CarHardwareManager
+    private val hardwareMan: CarHardwareManager by lazy {
+        ctx.getCarService(CarContext.HARDWARE_SERVICE) as CarHardwareManager
+    }
     private var energyLevel: EnergyLevel? = null
     private val permissions = if (BuildConfig.FLAVOR_automotive == "automotive") {
         listOf(
@@ -366,16 +368,19 @@ class MapScreen(ctx: CarContext, val session: EVMapSession) :
             })
             return
 
-        println("Setting up energy level listener")
-
-        val exec = ContextCompat.getMainExecutor(carContext)
-        hardwareMan.carInfo.addEnergyLevelListener(exec, ::onEnergyLevelUpdated)
+        if (supportsCarApiLevel3(carContext)) {
+            println("Setting up energy level listener")
+            val exec = ContextCompat.getMainExecutor(carContext)
+            hardwareMan.carInfo.addEnergyLevelListener(exec, ::onEnergyLevelUpdated)
+        }
     }
 
     @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
     private fun removeListeners() {
-        println("Removing energy level listener")
-        hardwareMan.carInfo.removeEnergyLevelListener(::onEnergyLevelUpdated)
+        if (supportsCarApiLevel3(carContext)) {
+            println("Removing energy level listener")
+            hardwareMan.carInfo.removeEnergyLevelListener(::onEnergyLevelUpdated)
+        }
     }
 
     override fun onContentRefreshRequested() {

app/src/testGoogle/java/net/vonforst/evmap/auto/CarAppTest.kt

@@ -0,0 +1,42 @@
+package net.vonforst.evmap.auto
+
+import android.content.ComponentName
+import android.content.Intent
+import androidx.car.app.HandshakeInfo
+import androidx.car.app.testing.SessionController
+import androidx.car.app.testing.TestCarContext
+import androidx.car.app.testing.TestScreenManager
+import androidx.lifecycle.Lifecycle
+import androidx.test.core.app.ApplicationProvider
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.Robolectric
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.internal.DoNotInstrument
+
+@RunWith(RobolectricTestRunner::class)
+@DoNotInstrument
+class CarAppTest {
+    private val testCarContext =
+        TestCarContext.createCarContext(ApplicationProvider.getApplicationContext()).apply {
+            updateHandshakeInfo(HandshakeInfo("auto.testing", 1))
+        }
+
+    @Test
+    fun onCreateScreen_returnsExpectedScreen() {
+        val service = Robolectric.setupService(CarAppService::class.java)
+        val session = service.onCreateSession()
+        val controller = SessionController(
+            session, testCarContext,
+            Intent().setComponent(
+                ComponentName(testCarContext, CarAppService::class.java)
+            )
+        )
+        controller.moveToState(Lifecycle.State.CREATED)
+        val screenCreated =
+            testCarContext.getCarService(TestScreenManager::class.java).screensPushed.last()
+
+        // location permission required
+        assert(screenCreated is PermissionScreen)
+    }
+}