Add unit tests

Also make SdlManager default constructor package private

Author: noah-livio

android/sdl_android/src/androidTest/java/com/smartdevicelink/managers/SdlManagerTests.java

@@ -422,4 +422,20 @@ public void onResponse(int correlationId, RPCResponse response) {
         // Make sure the listener is called exactly once
         assertEquals("Listener was not called or called more/less frequently than expected", 1, listenerCalledCounter);
     }
+
+    @Test
+    public void testDisposeAfterRetryChangeRegistration() {
+        LockScreenConfig lockScreenConfig = new LockScreenConfig();
+        SdlManager sdlManager = createSampleManager("Test App", "test.test.test", lockScreenConfig);
+        sdlManager.retryChangeRegistration();
+        sdlManager.dispose();
+    }
+
+    @Test
+    public void testRetryChangeRegistrationAfterDispose() {
+        LockScreenConfig lockScreenConfig = new LockScreenConfig();
+        SdlManager sdlManager = createSampleManager("Test App", "test.test.test", lockScreenConfig);
+        sdlManager.dispose();
+        sdlManager.retryChangeRegistration();
+    }
 }

android/sdl_android/src/main/java/com/smartdevicelink/managers/SdlManager.java

@@ -100,6 +100,7 @@ public void run() {
         }
     };
 
+    SdlManager(){}
 
     /**
      * Starts up a SdlManager, and calls provided callback called once all BaseSubManagers are done setting up