South Africa’s former president Nelson Mandela spent the night in hospital in the capital Pretoria to undergo tests, officials said.The office of President Jacob Zuma said 94-year-old Mr Mandela was doing well and there was "no cause for alarm”.South African President Jacob Zuma has visited him in hospital and says he "looks well after a restful night”, Zuma’s spokesperson said.The president has been reassured that Mr Mandela is in the hands of a competent medical team at the hospital in Pretoria, Mac Maharaj told the BBC.Mr Mandela was taken from his home in the rural village of Qunu, in Eastern Cape province, to hospital in the capital on Saturday.Local media report that the decision to move him was taken so quickly, some family members and his own foundation were initially unaware it had happened.Mr Mandela spent more than two decades in jail under the white minority apartheid regime.He served as South Africa’s first black president between 1994 and 1999, and received the Nobel Peace Prize in 1993.Mr Mandela has rarely appeared in public since 2004, when he retired from public life.In January 2011 he was treated for a serious chest infection, and a year later underwent a diagnostic procedure for an abdominal problem.Officials said on Saturday that he would need medical attention "from time to time” because of his age.Agencies