new_contents: import os
  import pytest
  import numpy as np
  from sqlalchemy import create_engine
  from blaze import discover
  from blaze.data.drop import drop, HDF5, SQL, CSV
  from blaze.data.drop import Collection
  
  
  data = [(1, 32.4, 'Alice'),
          (2, 234.24, 'Bob'),
          (4, -430.0, 'Joe')]
  
  
  x = np.array(data, dtype=[('id', int), ('amount', float), ('name', '|S5')])
  
  
  schema = discover(x).subshape[0]
  
  
  class TestDrop(object):
      def test_hdf5(self, h):
          h = HDF5('test.h5', '/test', schema=schema)
          h.extend(data)
          drop(h)
          with pytest.raises(Exception):
              pass
  
      def test_sql(self):
          engine = create_engine('sqlite:///:memory:')
          sql = SQL(engine, 'test', schema=schema)
          sql.extend(data)
          drop(sql)
  
      def test_csv(self):
          csv = CSV('test.csv', schema=schema)
          csv.extend(data)
          drop(csv)
          assert not os.path.exists('test.csv')
  
      def test_mongo(self):
          pass
  
subject: Add dropping tests