public void TestBadCustomerList()
        {
            var customerManagerMock = new Mock <ICustomerManager>();

            customerManagerMock.Setup(m =>
                                      m.GetAllCustomers())
            .Returns(
                new List <Customer>
            {
                new Customer
                {
                    Name    = "Adam",
                    Address = "Örebro",
                    Borrows = new List <Borrow> {
                        new Borrow {
                            DateOfBorrow = new DateTime(2018, 10, 10), Book = new Book {
                            }
                        }
                    }
                },
                { new Customer
                  {
                      Name    = "Adam",
                      Address = "Örebro",
                      Borrows = new List <Borrow> {
                          new Borrow {
                              DateOfBorrow = new DateTime(2018, 10, 10), Book = new Book {
                              }
                          }
                      }
                  } },
                { new Customer
                  {
                      Name    = "Adam",
                      Address = "Örebro",
                      Borrows = new List <Borrow> {
                          new Borrow {
                              DateOfBorrow = new DateTime(2018, 10, 10), Book = new Book {
                              }
                          }
                      }
                  } },
                { new Customer
                  {
                      Name    = "Adam",
                      Address = "Örebro",
                      Borrows = new List <Borrow> {
                          new Borrow {
                              DateOfBorrow = new DateTime(2018, 10, 10), Book = new Book {
                              }
                          }
                      }
                  } },
                { new Customer
                  {
                      Name    = "Adam",
                      Address = "Örebro",
                      Borrows = new List <Borrow> {
                          new Borrow {
                              DateOfBorrow = new DateTime(2018, 10, 10), Book = new Book {
                              }
                          }
                      }
                  } },
                { new Customer
                  {
                      Name    = "Lars",
                      Address = "Kumla",
                      Borrows = new List <Borrow> {
                          new Borrow {
                              DateOfBorrow = new DateTime(2019, 10, 10), Book = new Book {
                              }
                          }, new Borrow {
                              DateOfBorrow = new DateTime(2018, 10, 10), Book = new Book {
                              }
                          }
                      }
                  } }
            }
                );

            var CustomerAPI     = new CustomerAPI(customerManagerMock.Object, null, null);
            var badCustomerList = CustomerAPI.GetBadCustomers();

            Assert.AreEqual(badCustomerList.Count, 5);
        }