The Cambridge English Placement Test is a comprehensive, international assessment of English ability that covers all the key language-learning skills. Results are mapped to the Common European Framework of Reference for Languages (CEFR) – the international standard for describing language ability.
You can get more information about the test from
http://www.cambridgeenglish.org/find-a-centre/exam-centres/support-for-centres/placing-students-in-the-right-exam/
Sample Test:
https://www.metritests.com/metricatestdelivery/Assessment/Assignment?test=cept_demo