public void DeleteSettings()
        {
            var mockSet = new Mock <DbSet <Settings> >();

            var mockContext = new Mock <ImportContext>();

            mockContext.Setup(m => m.Settings).Returns(mockSet.Object);

            var settings = new SettingsRepository(mockContext.Object);

            settings.DeleteSetting("keyTest");

            mockSet.Verify(m => m.Remove(It.IsAny <Settings>()), Times.Once);
        }