public void AddShipper_GivenANewShipper_AddsToDatabase()
{
// arrange
Mock <DbSet <Shipper> > mockSet = new Mock <DbSet <Shipper> >();
Mock <ShippingDb> mockContext = new Mock <ShippingDb>();
mockContext.Setup(c => c.Shippers).Returns(mockSet.Object);
ShipperRepository sut = new ShipperRepository(mockContext.Object);
Shipper shipper = new Shipper()
{
ID = 200
};
// act
sut.AddShipper(shipper);
// assert
mockSet.Verify(s => s.Add(It.Is <Shipper>(a => a.ID == 200)), Times.Once());
mockContext.Verify(c => c.SaveChanges(), Times.Once());
}