public void ThrowException_WhenPassedVisitIsNull()
            {
                // Arrange
                var efRepositoryMock = new Mock <IEfRepository <Visit> >();
                var commitMock       = new Mock <ISaveContext>();

                var visitsService = new VisitsService(efRepositoryMock.Object, commitMock.Object);

                efRepositoryMock.Setup(r => r.Update(It.IsAny <Visit>()));

                // Act & Assert
                Assert.ThrowsException <ArgumentNullException>(() => visitsService.Update(null));
            }
            public void CallRepositoryUpdateAndCommitOnce_WhenPassedVisitIsNotNull()
            {
                // Arrange
                var efRepositoryMock = new Mock <IEfRepository <Visit> >();
                var commitMock       = new Mock <ISaveContext>();

                var visitsService = new VisitsService(efRepositoryMock.Object, commitMock.Object);

                var visit = new Visit();

                efRepositoryMock.Setup(r => r.Update(visit));
                commitMock.Setup(c => c.Commit());

                // Act
                visitsService.Update(visit);

                // Assert
                efRepositoryMock.Verify(r => r.Update(visit), Times.Once);
                commitMock.Verify(c => c.Commit(), Times.Once);
            }