JOHANNESBURG: Former South Africa captain Faf du Plessis on Wednesday announced his retirement from Test cricket to focus on the shorter formats with T20 being his priority.The 36-year-old made the announcement through a statement on his instagram page."It has been a year of refinement in the fire for us all. Uncertain were the times but they brought clarity for me in many aspects. My heart is clear and time is right to walk into a new chapter," du Plessis posted."It has been an