Closes mozilla-mobile#4458: Use cached registration token from ADM if available

Since the ADM instance does not live in the app itself, clearing app
data doesn't remove the registration ID for it. This means that we never
initialize the native PushManager with the cached code.

Our fix is straight-forward: if we have a cached registration ID, invoke
the `PushProcessor#onNewToken` and follow the regular flow.

Author: jonalmeida

components/lib/push-amazon/src/main/java/mozilla/components/lib/push/amazon/AbstractAmazonPushService.kt

@@ -28,8 +28,12 @@ abstract class AbstractAmazonPushService : ADMMessageHandlerBase("AbstractAmazon
 
     override fun start(context: Context) {
         adm = ADM(context)
-        if (adm.registrationId == null) {
+
+        val registrationId = adm.registrationId
+        if (registrationId == null) {
             adm.startRegister()
+        } else {
+            PushProcessor.requireInstance.onNewToken(registrationId)
         }
     }
 

components/lib/push-amazon/src/test/java/mozilla/components/lib/push/amazon/AbstractAmazonPushServiceTest.kt

@@ -22,7 +22,11 @@ import org.junit.Assert.assertTrue
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
-import org.mockito.Mockito
+import org.mockito.Mockito.anyString
+import org.mockito.Mockito.never
+import org.mockito.Mockito.reset
+import org.mockito.Mockito.verify
+import org.mockito.Mockito.verifyZeroInteractions
 import org.robolectric.RobolectricTestRunner
 import org.robolectric.annotation.Config
 import org.robolectric.annotation.Implementation
@@ -36,15 +40,23 @@ class AbstractAmazonPushServiceTest {
 
     @Before
     fun setup() {
-        Mockito.reset(processor)
+        reset(processor)
         PushProcessor.install(processor)
     }
 
+    @Test
+    fun `if registrationId exists startRegister invokes onNewToken`() {
+        val testService = TestService()
+
+        testService.start(testContext)
+        verify(processor).onNewToken(anyString())
+    }
+
     @Test
     fun `onNewToken passes token to processor`() {
         service.onRegistered("token")
 
-        Mockito.verify(processor).onNewToken("token")
+        verify(processor).onNewToken("token")
     }
 
     @Test
@@ -61,7 +73,7 @@ class AbstractAmazonPushServiceTest {
         messageIntent.putExtras(bundleExtra)
         service.onMessage(messageIntent)
 
-        Mockito.verify(processor).onMessageReceived(captor.capture())
+        verify(processor).onMessageReceived(captor.capture())
 
         assertEquals("1234", captor.value.channelId)
         assertEquals("contents", captor.value.body)
@@ -82,7 +94,7 @@ class AbstractAmazonPushServiceTest {
 
         service.onRegistrationError("123")
 
-        Mockito.verify(processor).onError(captor.capture())
+        verify(processor).onError(captor.capture())
 
         assertTrue(captor.value is PushError.Registration)
         assertTrue(captor.value.desc.contains("registration failed"))
@@ -98,7 +110,7 @@ class AbstractAmazonPushServiceTest {
         messageIntent.putExtras(bundleExtra)
         service.onMessage(messageIntent)
 
-        Mockito.verify(processor).onError(captor.capture())
+        verify(processor).onError(captor.capture())
 
         assertTrue(captor.value is PushError.MalformedMessage)
         assertTrue(captor.value.desc.contains("NoSuchElementException"))
@@ -109,15 +121,37 @@ class AbstractAmazonPushServiceTest {
         val messageIntent = Intent()
         service.onMessage(messageIntent)
 
-        Mockito.verifyZeroInteractions(processor)
+        verifyZeroInteractions(processor)
     }
 
     @Test
     fun `service available reflects Amazon Device Messaging availability`() {
         assertTrue(service.isServiceAvailable(testContext))
     }
+}
+
+class TestService : AbstractAmazonPushService()
+
+@RunWith(RobolectricTestRunner::class)
+@Config(shadows = [ShadowADMMessageHandlerBase::class, ShadowADM2::class])
+class AbstractAmazonPushServiceRegistrationTest {
+
+    private val processor: PushProcessor = mock()
+    private val service = TestService()
+
+    @Before
+    fun setup() {
+        reset(processor)
+        PushProcessor.install(processor)
+    }
 
-    class TestService : AbstractAmazonPushService()
+    @Test
+    fun `if registrationId does NOT exist startRegister never invokes onNewToken`() {
+        val testService = TestService()
+
+        testService.start(testContext)
+        verify(processor, never()).onNewToken(anyString())
+    }
 }
 
 /**
@@ -146,4 +180,23 @@ class ShadowADM {
     fun __constructor__(context: Context) {}
 
     fun isSupported() = true
+
+    fun getRegistrationId() = "123"
 }
+
+/**
+ * Custom Shadow for [ADM] where the registration ID is null. Currently, we have no way to alter the
+ * Shadow class inside of the service, so this is our work around.
+ */
+@Implements(ADM::class)
+class ShadowADM2 {
+    @Implementation
+    @Suppress("UNUSED_PARAMETER")
+    fun __constructor__(context: Context) {}
+
+    fun isSupported() = true
+
+    fun getRegistrationId(): String? = null
+
+    fun startRegister() {}
+}