old_contents: import unittest
  
  from cupy import testing
  
  
  @testing.parameterize(*testing.product({
      'shape': [(3, 3), (2, 2, 2), (3, 5), (5, 3)],
      'val': [1, 0],
      'wrap': [True, False],
  }))
  @testing.gpu
  class TestInsert(unittest.TestCase):
  
      _multiprocess_can_split_ = True
  
      @testing.for_all_dtypes()
      @testing.numpy_cupy_array_equal(accept_error=False)
      def test_fill_diagonal(self, xp, dtype):
          a = testing.shaped_arange(self.shape, xp, dtype)
          xp.fill_diagonal(a, val=self.val, wrap=self.wrap)
          return a
  
new_contents: import unittest
  
  from cupy import testing
  
  
  @testing.parameterize(*testing.product({
      'shape': [(3, 3), (2, 2, 2), (3, 5), (5, 3)],
      'val': [1, 0],
      'wrap': [True, False],
  }))
  @testing.gpu
  class TestInsert(unittest.TestCase):
  
      _multiprocess_can_split_ = True
  
      @testing.for_all_dtypes()
      @testing.numpy_cupy_array_equal(accept_error=False)
      def test_fill_diagonal(self, xp, dtype):
          a = testing.shaped_arange(self.shape, xp, dtype)
          xp.fill_diagonal(a, val=self.val, wrap=self.wrap)
          return a
  
      @testing.for_all_dtypes()
      @testing.numpy_cupy_raises()
      def test_1darray(self, xp, dtype):
          a = testing.shaped_arange(5, xp, dtype)
          xp.fill_diagonal(a, val=self.val, wrap=self.wrap)
  
subject: Add fail tests