A containing product is defined as: “a product containing one or more light sources, including, but not limited to, luminaires that can be taken apart to allow separate verification of the contained light source(s), household appliances containing light source(s), furniture (shelves, mirrors, display cabinets) containing light source(s).”
What counts to define a product as a light source is the possibility to remove the light source for verification, without permanent damage to the contained light source (while if the containing product gets damaged is not relevant). If the light source(s) cannot be removed from the containing product without being permanently damaged, the entire containing product should be defined as a light source (including the registration in the products database EPREL and bearing an EU energy label).
If we take the example of a luminaire with three light sources. If the three light sources are removable for verification purposes, then they are each of them in scope of ecodesign.
If the three light sources are not removable for verification purposes, the entire luminaire is a light source and in its entirety will need to meet the requirements of the regulation (thus the testing of the product will cover the three light sources on the luminaire altogether).
Disclaimer: Please note that the European Commission cannot provide a legally binding interpretation of the EU legislation, as this is the sole competence of the European Court of Justice. Any remarks from the European Commission services are without prejudice to the position the Commission might take should related cases arise in a procedure before the Court of Justice.