public async Task AddOrUpdate_ValidIdAndDocument_CallsApplicationService()
        {
            // Arrange
            var service = new Mock <IDocumentService>();

            var target = new DocumentsController(service.Object);

            var fixture = new Fixture();

            var model      = fixture.Create <AddOrUpdateDocumentModel>();
            var documentId = Guid.NewGuid();

            // Act
            await target.AddOrUpdate(documentId, model);

            // Assert
            service.Verify(i => i.Save(documentId, It.IsAny <DocumentDto>()));
        }