public void Given_ValidId_GetById_Should_Return_Dto()
    {
        //Arrange
        var validId = 1;
        var fakes   = new List <Rates>()
        {
            new Rates {
                RateId = validId
            }
        }
        var mock = new Mock <IDbContext>();

        //Assuming IDbContext.Rates.GetAll() returns an IEnumerable<Rates>
        mock.Setup(m => m.Rates.GetAll()).Returns(fakes);
        var sut = new RateService(mock.Object);
        //Act
        var result = sut.GetById(validId);

        //Assert
        Assert.IsNotNull(result);
    }