How close is the Pakistan-China military co-operation?

After many years, Pakistan has acquired the Chinese J-10C Firebird fighter jets. Pakistan's interior ministry says it's in response to India’s purchase of the French Rafale aircraft. China and Pakistan have long been allies, and they co-operate on a number of issues in the region. And one uniting factor is their outlook on India. Double Check digs deep to see what exactly brings Beijing and Islamabad together. #Pakistan #China