new_contents: from mock import Mock
  
  from malcolm.modules.scanning.blocks import unrolling_block
  from malcolm.testutil import ChildTestCase
  
  
  class TestUnrollingBlock(ChildTestCase):
      def test_unrolling_block(self):
          self.create_child_block(
              unrolling_block,
              Mock(),
              mri="TEST:MRI",
          )
  
subject: Add test to instantiate unrolling block