code: def _inject_config_source(self, source_filename, files_to_inject):
          
          # src_path = os.path.join(self.directory.root_dir, source_filename)
          # src_exec = "[ -r %s ] && . %s" % (src_path, src_path)
          src_exec = "[ -r {0} ] && . {0}".format(os.path.join(self.directory.root_dir, source_filename))
          # The ridiculous construction above is necessary to avoid failing tests(!)
  
          for config_file in files_to_inject:
              config_path = os.path.expanduser(os.path.join("~", config_file))
              if os.path.exists(config_path):
                  self.injections.inject(config_path, src_exec)
                  break
          else:
              config_file = files_to_inject[0]
              config_path = os.path.expanduser(os.path.join("~", config_file))
              self.logger.info("No config files found to source %s, creating ~/%s!" % (source_filename, config_file))
              self.injections.inject(config_path, src_exec)
  
          return (config_file, config_path)
docs: Inject existing environmental config with namespace sourcing.
          Returns a tuple of the first file name and path found.