       expect(C).not.toBe B # not in place?
       expect(B).toEqual A2_A # source unchanged ?
 
+
   describe 'minus() function', ->
 
     it 'subtrats two matrices to a new matrix', ->

                            5, 6 ], 2 # expected result?
      expect(C).not.toBe B # not in place?
      expect(B).toEqual A # source unchanged ?

  describe 'mult() function', ->


      expect(A2).toEqual A # source unchanged ?
      expect(B2).toEqual B # source unchanged ?


  describe 'toString() function', ->

    it 'should return the matrix as string', ->
      expect(A.toString()).toBe '1 3 5\n2 4 6'


  describe 'I()', ->

    it 'creates a new identity matrix', ->
      expect(M.I(3)).toEqual M [ 1, 0, 0
                                 0, 1, 0
                                 0, 0, 1 ]
      expect(M.I(3, 2)).toEqual M [ 1, 0, 0
                                    0, 1, 0 ], 3
