class_docstr: Provides context for a user acceptance test.
  
  Context consists of an environment suitable for run commands (used
  extensively by the uat) and the setting of Guild home to the
  global `GUILD_HOME` (required by in-process commands that use
  Guild home).
  
  Note that the UAT Guild home is, by default, local to the UAT
  workspace and not the current process Guild home.
code: def __enter__(self):
      self._env.__enter__()
      self._guild_home.__enter__()
  
imports: import fnmatch
  import os
  import re
  import sys
  import tempfile
  import guild
  from guild import _test
  from guild import config
  from guild import pip_util
  from guild import util
label_desc: Use image node_id 2 for calling the UATContext obj's underlying member method code with example usage: obj.__enter__() without return types