test_index = ->
  run_test [

    "A=[[A11,A12],[A21,A22]]",
    "",

    "A[1,1]",
    "A11",

    "A[1,2]",
    "A12",

    "A[2,1]",
    "A21",

    "A[2,2]",
    "A22",

    "A[1]",
    "[A11,A12]",

    "A[1][2]",
    "A12",

    "A[2]",
    "[A21,A22]",

    "A[1]=[B11,B12]",
    "",

    "A",
    "[[B11,B12],[A21,A22]]",

    "A[2]=[B21,B22]",
    "",

    "A",
    "[[B11,B12],[B21,B22]]",

    "A=[[0,0],[0,0]]",
    "",

    "A[1,1]",
    "0",

    # index of scalar should throw an error

    "1[2]",
    "Stop: trying to access a scalar as a tensor",

    # clean up -----------------

    "clearall",
    "",

    # index of a non-allocated tensor
    # or index with a symbol instead of
    # a number

    "a[0]",
    "a[0]",

    "a[0,2]",
    "a[0,2]",


    "a[b]",
    "a[b]",

    "a[b,c]",
    "a[b,c]",

    "a = [1,2,3]",
    "",

    "a[b]",
    "a[b]",

  ]