code: def test_get_source_files(self):
      modules = [Extension("foo", ["xxx"])]
      dist = Distribution({"name": "xx", "ext_modules": modules})
      cmd = build_ext(dist)
      cmd.ensure_finalized()
      self.assertEqual(cmd.get_source_files(), ["xxx"])
  
imports: import sys
  import os
  from StringIO import StringIO
  import textwrap
  from distutils.core import Extension, Distribution
  from distutils.command.build_ext import build_ext
  from distutils import sysconfig
  from distutils.tests import support
  from distutils.errors import DistutilsSetupError, CompileError, DistutilsPlatformError
  import unittest
  from test import test_support
label_desc: Use image node_id 8 for calling the BuildExtTestCase obj's underlying member method code with example usage: obj.test_get_source_files() without return types