public void ModularExponentiationCorrect(int b, int e, int m, int expectedRes)
        {
            var modularExponentiation = new ModularExponentiation();
            var actualRes             = modularExponentiation.ModularPow(b, e, m);

            actualRes.Should().Be(expectedRes);
        }
        public void ModularExponentiationNegativeMod(int b, int e, int m)
        {
            var    modularExponentiation = new ModularExponentiation();
            Action res = () => modularExponentiation.ModularPow(b, e, m);

            res.Should().Throw <ArgumentException>()
            .WithMessage(String.Format("{0} is not a positive integer", m));
        }