class_docstr: Most tests done in the base class LinearOperatorDerivedClassTest.
class_docstr_tok: ["Most","tests","done","in","the","base","class","LinearOperatorDerivedClassTest","."]
code: def test_non_square_operator_raises(self):
      operators = [
          [
              linalg.LinearOperatorFullMatrix(
                  rng.rand(3, 4), is_square=False
              )
          ],
          [
              linalg.LinearOperatorFullMatrix(rng.rand(4, 4)),
              linalg.LinearOperatorFullMatrix(rng.rand(4, 4)),
          ],
      ]
      with self.assertRaisesRegex(ValueError, "must be square"):
          block_lower_triangular.LinearOperatorBlockLowerTriangular(
              operators
          )
  
imports: import numpy
  from tensorflow.python.eager import backprop
  from tensorflow.python.eager import context
  from tensorflow.python.framework import config
  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_block_lower_triangular
  from tensorflow.python.ops.linalg import linear_operator_test_util
  from tensorflow.python.ops.linalg import linear_operator_util
  from tensorflow.python.platform import test
label_desc: Use image node_id 13 for calling the SquareLinearOperatorBlockLowerTriangularTest obj's underlying member method code with example usage: obj.test_non_square_operator_raises() without return types