public async void GetSecureDocumentsShouldReturnDocument()
        {
            // Arrange
            var document           = new DocumentBuilder().Build();
            var documentToDownload = new DocumentToDownload()
            {
                MediaType = document.MediaType, FileData = new byte[] { }
            };
            var mockDocumentsService = new Mock <IDocumentsService>();
            var assetId = "asset-id";
            var slug    = "slug";

            // Mock
            mockDocumentsService.Setup(o => o.GetSecureDocument(assetId, slug)).ReturnsAsync(documentToDownload);

            var documentsController = new DocumentsController(mockDocumentsService.Object);

            // Act
            var result = await documentsController.GetSecureDocument(slug, assetId) as FileContentResult;

            // Assert
            mockDocumentsService.Verify(o => o.GetSecureDocument(It.IsAny <string>(), It.IsAny <string>()), Times.Once);
            result.Should().NotBeNull();
            result.ContentType.Should().Be(document.MediaType);
        }