I took the Test of Proficiency in Korean (TOPIK) last month and I passed at the top level, which is Level 6. This test is the leading Korean counterpart to the various standardized tests non-English speakers take to prove their ability in English, such as the TOEFL and TOEIC tests.
I am using the following screennshot as a placeholder until I get the printed certificate from NIIED, the Korean National Institute for International Education, and can upload it here.