@Test
public void testCalculateI() {

    double radiance = 50;
    float sunSpectralFlux = 10;
    double sunZenith = 45;
    double i = cloudPn.calculateI(radiance, sunSpectralFlux, sunZenith);
    assertEquals("calculated i", (radiance / (sunSpectralFlux * Math.cos(sunZenith * MathUtils.DTOR))), i, 0.00001);
}