How can I unit test an Android Activity that acts on Accelerometer?

Question

I am starting with an Activity based off of this ShakeActivity and I want to write some unit tests for it. I have written some small unit tests for Android activities befor

Answer 1

  public  class SensorService implements SensorEventListener {
/**
     * Accelerometer values
     */
    private float accValues[] = new float[3];
     @Override
     public void onSensorChanged(SensorEvent event) {

          if (sensorEvent.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
            accValues[0] = sensorEvent.values[0];
            accValues[1] = sensorEvent.values[1];
            accValues[2] = sensorEvent.values[2];
        }

     }
} 

you can test above piece of code by following way

@Test
    public void testOnSensorChangedForAcceleratorMeter() throws Exception {
        Intent intent=new Intent();
        sensorService.onStartCommand(intent,-1,-1);

        SensorEvent sensorEvent=getEvent();
        Sensor sensor=getSensor(Sensor.TYPE_ACCELEROMETER);
        sensorEvent.sensor=sensor;
        sensorEvent.values[0]=1.2345f;
        sensorEvent.values[1]=2.45f;
        sensorEvent.values[2]=1.6998f;
        sensorService.onSensorChanged(sensorEvent);

        Field field=sensorService.getClass().getDeclaredField("accValues");
        field.setAccessible(true);
        float[] result= (float[]) field.get(sensorService);
        Assert.assertEquals(sensorEvent.values.length,result.length);
        Assert.assertEquals(sensorEvent.values[0],result[0],0.0f);
        Assert.assertEquals(sensorEvent.values[1],result[1],0.0f);
        Assert.assertEquals(sensorEvent.values[2],result[2],0.0f);
    } 




private Sensor getSensor(int type) throws NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException, NoSuchFieldException {
            Constructor constructor = Sensor.class.getDeclaredConstructor(new Class[0]);
            constructor.setAccessible(true);
            Sensor sensor= constructor.newInstance(new Object[0]);

            Field field=sensor.getClass().getDeclaredField("mType");
            field.setAccessible(true);
            field.set(sensor,type);
            return sensor;
        }



private SensorEvent getEvent() throws NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
        Constructor constructor = SensorEvent.class.getDeclaredConstructor(int.class);
        constructor.setAccessible(true);
        return constructor.newInstance(new Object[]{3});
    }