public void When_we_list_all_the_natural_numbers_below_10_that_are_multiples_of_3_or_5_the_sum_must_be_23()
 {
     string expected = "23";
     IEulerProblem problem = new EulerProblem001(1, 10);
     string result = problem.Solve();
     Assert.Same(expected, result);
 }
 public void WhenWeListAllTheNaturalNumbersBelow10ThatAreMultiplesOf3Or5TheSumMustBe23()
 {
     const int expected = 23;
     var result = new EulerProblem001(1, 9).Solve();
     result.Should().Be(expected);
 }