public void ShouldChange()
        {
            // Arrange
            var tracking = new TrackNumberOfFaces();

            // Act
            var result = tracking.HasChanged(new FrameState(new List <Face>()), new FrameState(new List <Face> {
                new Face()
            }));

            // Assert
            result.ShouldBeTrue();
        }
        public void ShouldChangeEvenWhenNull()
        {
            // Arrange
            var tracking = new TrackNumberOfFaces();
            var face     = new Face();

            // Act
            var result = tracking.HasChanged(null, new FrameState(new List <Face> {
                face
            }));

            // Assert
            result.ShouldBeTrue();
        }
        public void ShouldNotChange()
        {
            // Arrange
            var tracking = new TrackNumberOfFaces();
            var face     = new Face();

            // Act
            var result = tracking.HasChanged(new FrameState(new List <Face> {
                face
            }), new FrameState(new List <Face> {
                face
            }));

            // Assert
            result.ShouldBeFalse();
        }