As an Erasmus+ funded student it is a mandatory requirement that you take the first assessment test unless you are a native speaker of the coutry you will be visiting.
Students will be sent an invitation to take the online test and if appropriate (i.e if their score is below C1) will be allocated a licence to undertake the course. There is another test at the end. This is a good indicator to you how well you have done during the course. However, should your score not improve you will not be penalised and will still receive your Erasmus+ grant.
The university only receives a certain number of licences for these courses so if you are one of the lucky ones, grab the opportunity.