test_adj = ->
  run_test [

    "adj([[a,b],[c,d]])",
    "[[d,-b],[-c,a]]",

    "adj([[1,2],[3,4]])",
    "[[4,-2],[-3,1]]",

    "adj([[2,3,-2,5],[6,-2,1,4],[5,10,3,-2],[-1,2,2,3]])",
    "[[-4,-177,-73,194],[-117,117,-99,-27],[310,-129,-44,-374],[-130,-51,71,-211]]",
  ]