# File lib/rspec/core/formatters/base_formatter.rb, line 109
        def backtrace_line(line)
          return nil if configuration.cleaned_from_backtrace?(line)
          line.sub!(File.expand_path("."), ".")
          line.sub!(/\A([^:]+:\d+)$/, '\\1')
          return nil if line == '-e:1'
          line
        end