private void ExtractMmsiFromHtml_OnReceivedNullCollection_returnsZeroValue()
        {
            _creatorMock.Setup(mock => mock.CreateNodeCollection(It.IsAny <string>(), It.IsAny <string>())).Returns((HtmlNodeCollection)null);

            int result = _service.ExtractMmsiFromHtml("some_html");

            Assert.Equal(0, result);
            _creatorMock.Verify(mock => mock.CreateNodeCollection(It.IsAny <string>(), It.IsAny <string>()), Times.Once);
        }