require 'set'

describe "Set#flatten_merge" do
  it "is protected" do
    Set.should have_protected_instance_method("flatten_merge")
  end

  it "flattens the passed Set and merges it into self" do
    set1 = Set[1, 2]
    set2 = Set[3, 4, Set[5, 6]]

    set1.send(:flatten_merge, set2).should == Set[1, 2, 3, 4, 5, 6]
  end

  it "raises an ArgumentError when trying to flatten a recursive Set" do
    set1 = Set[1, 2, 3]
    set2 = Set[5, 6, 7]
    set2 << set2

    lambda { set1.send(:flatten_merge, set2) }.should raise_error(ArgumentError)
  end
end
