If you want to accredit your command of Spanish, you have the following options:
1) URV exams
Register on a Spanish course organised by the URV's Language Service (semester-long courses: September-December or February-May) and pass the final exam (A1, A2, B1). Check the courses on offer here.
2) Cervantes Institute exams at the URV
The DELE exams (Diplomas in Spanish as a Foreign Language) of the Cervantes Institute are the official Spanish qualifications for foreigners and are accepted all over the world. The URV has an agreement with the Institute by which it acts as an examining centre for these certificates. The exams are organised by the Centre for Hispanic Studies on the internationally designated days (November, May and August). You will find information about these exams on the website of the Centre for Hispanic Studies and the general information about the DELE exams on the website of the Cervantes Institute.