Das Goethe-Institut in Prague, Czech Republic. The Goethe-Institut is a non-profit German cultural exchange association operating worldwide in 159 locations. It promotes the study of the German language, encourages cultural exchange, and fosters knowledge about present-day Germany by providing information on culture, society, and politics, incl. films, music, theater, and literature, cultural societies, reading rooms & exam and language centers. The organization is named after the famous German poet Johann Wolfgang von Goethe and was founded in 1951 as the successor to the Deutsche Akademie that had existed since 1925.
Today, the Goethe-Institut offers e-learning German language courses online as well as physical locations. It has developed a series of exams for learners of German as a foreign language (Deutsch als Fremdsprache, DaF) at all levels, A1 up to C2. These can be taken both in Germany and abroad, and have been adapted to fit into the CEFL, the standard for European language testing. There also is the Großes Deutsches Sprachdiplom, which is at a higher level than the highest CEFL certificate. Click to find a Goethe Institute location in your country or within Germany.
Working link: https://www.goethe.de/en/wwt.html