class_docstr: Most tests done in the base class LinearOperatorDerivedClassTest.
class_docstr_tok: ["Most","tests","done","in","the","base","class","LinearOperatorDerivedClassTest","."]
code: def test_empty_or_one_operators_raises(self):
      with self.assertRaisesRegex(ValueError, ">=1 operators"):
          kronecker.LinearOperatorKronecker([])
  
imports: import numpy
  from tensorflow.python.eager import backprop
  from tensorflow.python.framework import config
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  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_kronecker
  from tensorflow.python.ops.linalg import linear_operator_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 9 for calling the SquareLinearOperatorKroneckerTest obj's underlying member method code with example usage: obj.test_empty_or_one_operators_raises() without return types