undef_spec.rb

require_relative '../spec_helper'

describe "The undef keyword" do
  describe "undefines a method" do
    before :each do
      @undef_class = Class.new do
        def meth(o); o; end
      end
      @obj = @undef_class.new
      @obj.meth(5).should == 5
    end

    it "with an identifier" do
      @undef_class.class_eval do
        undef meth
      end
      -> { @obj.meth(5) }.should raise_error(NoMethodError)
    end

    it "with a simple symbol" do
      @undef_class.class_eval do
        undef :meth
      end
      -> { @obj.meth(5) }.should raise_error(NoMethodError)
    end

    it "with a single quoted symbol" do
      @undef_class.class_eval do
        undef :'meth'
      end
      -> { @obj.meth(5) }.should raise_error(NoMethodError)
    end

    it "with a double quoted symbol" do
      @undef_class.class_eval do
        undef :"meth"
      end
      -> { @obj.meth(5) }.should raise_error(NoMethodError)
    end

    it "with an interpolated symbol" do
      @undef_class.class_eval do
        undef :"#{'meth'}"
      end
      -> { @obj.meth(5) }.should raise_error(NoMethodError)
    end

    it "with an interpolated symbol when interpolated expression is not a String literal" do
      @undef_class.class_eval do
        undef :"#{'meth'.to_sym}"
      end
      -> { @obj.meth(5) }.should raise_error(NoMethodError)
    end
  end

  it "allows undefining multiple methods at a time" do
    undef_multiple = Class.new do
      def method1; end
      def method2; :nope; end

      undef :method1, :method2
    end

    obj = undef_multiple.new
    obj.respond_to?(:method1).should == false
    obj.respond_to?(:method2).should == false
  end

  it "raises a NameError when passed a missing name" do
    Class.new do
      -> {
         undef not_exist
      }.should raise_error(NameError) { |e|
        # a NameError and not a NoMethodError
        e.class.should == NameError
      }
    end
  end
end