require 'set'

ruby_version_is "1.9" do
  describe "Set#keep_if" do
    before(:each) do
      @set = Set["one", "two", "three"]
    end

    it "yields every element of self" do
      ret = []
      @set.keep_if { |x| ret << x }
      ret.sort.should == ["one", "two", "three"].sort
    end

    it "keeps every element from self for which the passed block returns true" do
      @set.keep_if { |x| x.size != 3 }
      @set.size.should eql(1)

      @set.should_not include("one")
      @set.should_not include("two")
      @set.should include("three")
    end

    it "returns self" do
      @set.keep_if {}.should equal(@set)
    end

    it "returns an Enumerator when passed no block" do
      enum = @set.keep_if
      enum.should be_an_instance_of(enumerator_class)

      enum.each { |x| x.size != 3 }

      @set.should_not include("one")
      @set.should_not include("two")
      @set.should include("three")
    end
  end
end
