Fix for defining groups based on a custom filter class.

[robinroestenburg]

Problem

The following LineFilter example is mentioned in the documentation of SimpleCov. I tried this out and configured SimpleCov as follows:

class LineFilter < SimpleCov::Filter
  def passes?(source_file)
    source_file.lines.count < filter_argument
  end
end

SimpleCov.start 'rails' do
  add_group "Short files", LineFilter.new(5)
end

Instead of showing me the files that have less then 5 lines, the tab 'Short files' contains all files that are greater than or equal to 5 lines.

Fixes

The initial fix was removing the negation from the grouped method in lib/simplecov.rb. This led to some underlying problems in the SimpleCov::Filter classes.

I renamed the passes? method to matches? and also removed the negation that was present. The comments in the StringFilter and LineFilter class now match the code :) The changes made in test/test_filters.rb are trivial changes because of the removed negation.

I also had to change the filtered method in lib/simplecov.rb. This method now removes (or reject) all files that match the filter. This is functionally still the same.

I added a specific feature for testing the custom filter class (no existing one was present).

[colszowka]

Thanks, I've merged it in and updated the README accordingly. Also added a fallback passes? method to the filter baseclass including a deprecation warning so everyone's custom filter classes don't fail after the update. Release 0.5.4 in a couple minutes.