Private Sub PaymentTypeVerify()
    'Verify that the PaymentType function works correctly.

    Const Epsilon = 0.0000000001 ' 1E-10

    Debug.Assert Approx(PaymentType(0.1 / 12, 4 * 12, -400, 15771.264036612, 0), 0, Epsilon)
    Debug.Assert Approx(PaymentType(0.1 / 12, 4 * 12, -400, 15902.6912369171, 0), 1, Epsilon)
    
    Debug.Assert Approx(PaymentType(0.1 / 12, 4 * 12, 456.526501825451, -18000, 0), 0, Epsilon)
    Debug.Assert Approx(PaymentType(0.1 / 12, 4 * 12, 452.753555529373, -18000, 0), 1, Epsilon)

End Sub