class_docstr: A test case providing connections for tests.
  
  A connection for the test is always available as `self.conn`. Others can be
  created with `self.connect()`. All are closed on tearDown.
  
  Subclasses needing to customize setUp and tearDown should remember to call
  the base class implementations.
class_docstr_tok: ["A","test","case","providing","connections","for","tests",".","A","connection","for","the","test","is","always","available","as","`","self.conn","`",".","Others","can","be","created","with","`","self.connect","(",")","`",".","All","are","closed","on","tearDown",".","Subclasses","needing","to","customize","setUp","and","tearDown","should","remember","to","call","the","base","class","implementations","."]
code: def setUp(self):
      self._conns = []
  
imports: import re
  import os
  import sys
  import types
  import ctypes
  import select
  import operator
  import platform
  import unittest
  from functools import wraps
  from ctypes.util import find_library
  from io import StringIO
  from io import TextIOBase
  from importlib import reload
  import psycopg2
  import psycopg2.errors
  import psycopg2.extensions
  from .testconfig import green, dsn, repl_dsn
label_desc: Use image node_id 1 for calling the ConnectingTestCase obj's underlying member method code with example usage: obj.setUp() without return types