class_docstr: Most tests done in the base class LinearOperatorDerivedClassTest.
class_docstr_tok: ["Most","tests","done","in","the","base","class","LinearOperatorDerivedClassTest","."]
code: def test_assert_non_singular(self):
      with self.assertRaisesOpError("non-invertible"):
          operator = linalg_lib.LinearOperatorZeros(num_rows=2)
          operator.assert_non_singular()
  
imports: import numpy
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.ops.linalg import linalg
  from tensorflow.python.ops.linalg import linear_operator_test_util
  from tensorflow.python.platform import test
label_desc: Use image node_id 6 for calling the LinearOperatorZerosTest obj's underlying member method code with example usage: obj.test_assert_non_singular() without return types