class RSpec::Core::Formatters::SnippetExtractor

Extracts code snippets by looking at the backtrace of the passed error and applies synax highlighting and line numbers using html.
@api private

def initialize(source=nil, beginning_line_number=nil, max_line_count=nil)

our usage
Copied from the 3.4 version, but with default overrides to cope with 
def initialize(source=nil, beginning_line_number=nil, max_line_count=nil)
  @source = source
  @beginning_line_number = beginning_line_number
  @max_line_count = max_line_count
end

def lines_around(file, line)

Returns:
  • (String) - lines around the target line within the file (2 above and 1 below).

Parameters:
  • line (Fixnum) -- line number
  • file (String) -- filename

Other tags:
    Api: - private 
def lines_around(file, line)
  if File.file?(file)
    lines = File.read(file).split("\n")
    min = [0, line-3].max
    max = [line+1, lines.length-1].min
    selected_lines = []
    selected_lines.join("\n")
    lines[min..max].join("\n")
  else
    "# Couldn't get snippet for #{file}"
  end
rescue SecurityError
  "# Couldn't get snippet for #{file}"
end

def post_process(highlighted, offending_line)

Returns:
  • (String) - completed snippet

Parameters:
  • offending_line (Fixnum) -- line where failure occured
  • highlighted (String) -- syntax-highlighted snippet surrounding the offending line of code

Other tags:
    Api: - private 
def post_process(highlighted, offending_line)
  new_lines = []
  highlighted.split("\n").each_with_index do |line, i|
    new_line = "<span class=\"linenum\">#{offending_line+i-2}</span>#{line}"
    new_line = "<span class=\"offending\">#{new_line}</span>" if i == 2
    new_lines << new_line
  end
  new_lines.join("\n")
end

def snippet(backtrace)

Other tags:
    See: #post_process -

Returns:
  • (String) - highlighted code snippet indicating where the test failure occured

Parameters:
  • backtrace (String) -- the backtrace from a test failure

Other tags:
    Api: - private 
def snippet(backtrace)
  raw_code, line = snippet_for(backtrace[0])
  highlighted = @@converter.convert(raw_code)
  if LegacyNullConverter == @@converter || (defined?(NullConverter) && @@converter.is_a?(NullConverter))
    highlighted << "\n<span class=\"comment\"># gem install syntax to get syntax highlighting</span>"
  end
  post_process(highlighted, line)
end

def snippet_for(error_line)

Other tags:
    See: #lines_around -

Returns:
  • (String) - lines around the target line within the file

Parameters:
  • error_line (String) -- file name with line number (i.e. 'foo_spec.rb:12')

Other tags:
    Api: - private 
def snippet_for(error_line)
  if error_line =~ /(.*):(\d+)/
    file = $1
    line = $2.to_i
    [lines_around(file, line), line]
  else
    ["# Couldn't get snippet for #{error_line}", 1]
  end
end