public async Task GetPhotosToTag()
{
var photoIds = _fixture.CreateMany <int>(5).ToArray();
var tags = _fixture.CreateMany <Tag>(5);
_photosService.Setup(m => m.GetTagsAndPhotos(photoIds))
.ReturnsAsync(tags);
var response = await _tagsController.GetPhotosToTag(photoIds);
_photosService.Verify(m => m.GetTagsAndPhotos(photoIds),
Times.Once);
Assert.IsType <OkObjectResult>(response);
var value = ((OkObjectResult)response).Value;
Assert.IsType <BatchSelectTags>(value);
var dto = value as BatchSelectTags;
Assert.Equal(tags.Count(), dto.Tags.Count);
}