If you have no German school-leaving certificate (nor a 'Sprachdiplom II' from a 'Deutsche Schule' abroad), you will need an official proof of advanced German language skills for admission to a study programme.
The DSH ('Deutsche Sprachprüfung für den Hochschulzugang ausländischer Studienbewerber') is a test of German for academic purposes and the general requirement for admission of international students to higher education institutions in Germany. It tests your language proficiency in terms of your ability to conduct your studies in German. Alternatively, the TestDaF is also recognized.
You are required to pass one of these exams before commencing your studies. The tests are offered at certain official centres.