public async Task AddEmploymentDays_AddsOnlyEmploymentDays()
{
// Arrange
var date = new DateTime(2018, 10, 10);
var shiftPattern = new List <string>()
{
"1", "2", "3", "4", "5"
};
// Act
var result = await date.AddEmploymentDays(3, shiftPattern);
// Assert
result.Should().Be(new DateTime(2018, 10, 15));
}