It is doable with the new components also, but you are better off just working with the legacy ones if all that you intend to study is lighting from the luminaires.
You can choose an illuminance based sky and set the value of illuminance to 0 to create darkness. Then you need to bring in the light fixture definition and any other shapes into the radiance folder. I wrote a script to do that (which is the Python component in the screenshot below: customLBToolsIAddIESComponent.py · GitHub).
The example file I modified to do this was lbt-grasshopper-samples/samples/honeybee-radiance/viewbased.gh at master · ladybug-tools/lbt-grasshopper-samples · GitHub . I forgot to save my modified gh file, or else I would have put that in here too 