text: from mpmath import nstr, matrix, inf
  
  def test_nstr():
      m = matrix([[0.75, 0.190940654, -0.0299195971],
                  [0.190940654, 0.65625, 0.205663228],
                  [-0.0299195971, 0.205663228, 0.64453125e-20]])
      assert nstr(m, 4, min_fixed=-inf) == \
      '''[    0.75  0.1909                    -0.02992]
  [  0.1909  0.6563                      0.2057]
  [-0.02992  0.2057  0.000000000000000000006445]'''
      assert nstr(m, 4) == \
      '''[    0.75  0.1909   -0.02992]
  [  0.1909  0.6563     0.2057]
  [-0.02992  0.2057  6.445e-21]'''
  