class Minitest::Test

def self.add_to_filter name
  @@filtered_names << "#{self}##{name}"
end

def self.filtered_names
  @@filtered_names
end

def self.focus name = nil
  if name then
    add_to_filter name
  else
    set_focus_trap
  end
end

def self.set_focus_trap
  meta = class << self; self; end
  meta.send :define_method, :method_added do |name|
    add_to_filter name
    meta.send :remove_method, :method_added
  end
end