Covid19 - Travelling & Documents
It's passenger's responsibiliy to check official regulations prior to booking, and again prior to departure, to ensure your eligibility to travel for any layover points in your itinerary and your end destination.
Taking into consideration that the health establishments keep publishing updated guidelines about the conditions that the travellers should met during the COVID period, you are kindly advised to contact the local authorities and the responsible airline for the relevant instructions before travel (i.e covid test).
You can find all relevant documentation details here.
Most of the European countries do require a negative PCR test & travelers are set under quarantine depending on the destination.
You are advised to check these prior to your booking, in order to avoid paying cancellation fees.