class_docstr: Test for tri-diagonal matrix related ops.
code: def testDiagonal(self):
      self._test(
          diags=[[0, 0, 0, 0], [1, 2, -1, -2], [0, 0, 0, 0]],
          rhs=[1, 2, 3, 4],
          expected=[1, 1, -3, -2],
      )
  
imports: import numpy
  from tensorflow.compiler.tests import xla_test
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors_impl
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gradients
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops.linalg import linalg_impl
  from tensorflow.python.platform import test
label_desc: Use image node_id 13 for calling the TridiagonalSolveOpsTest obj's underlying member method code with example usage: obj.testDiagonal() without return types