spec/ruby/core/kernel/remove_instance_variable_spec.rb


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require_relative '../../spec_helper'
require_relative 'fixtures/classes'

describe :kernel_remove_instance_variable, shared: true do
  it "returns the instance variable's value" do
    value = @instance.send :remove_instance_variable, @object
    value.should == "hello"
  end

  it "removes the instance variable" do
    @instance.send :remove_instance_variable, @object
    @instance.instance_variable_defined?(@object).should be_false
  end
end

describe "Kernel#remove_instance_variable" do
  before do
    @instance = KernelSpecs::InstanceVariable.new
  end

  it "is a public method" do
    Kernel.should have_public_instance_method(:remove_instance_variable, false)
  end

  it "raises a NameError if the instance variable is not defined" do
    -> do
      @instance.send :remove_instance_variable, :@unknown
    end.should raise_error(NameError)
  end

  it "raises a NameError if the argument is not a valid instance variable name" do
    -> do
      @instance.send :remove_instance_variable, :"@0"
    end.should raise_error(NameError)
  end

  it "raises a TypeError if passed an Object not defining #to_str" do
    -> do
      obj = mock("kernel remove_instance_variable")
      @instance.send :remove_instance_variable, obj
    end.should raise_error(TypeError)
  end

  it "raises a FrozenError if self is frozen" do
    o = Object.new
    o.freeze
    -> { o.remove_instance_variable(:@foo) }.should raise_error(FrozenError)
    -> { o.remove_instance_variable(:foo) }.should raise_error(NameError)
  end

  it "raises for frozen objects" do
    -> { nil.remove_instance_variable(:@foo) }.should raise_error(FrozenError)
    -> { nil.remove_instance_variable(:foo) }.should raise_error(NameError)
    -> { :foo.remove_instance_variable(:@foo) }.should raise_error(FrozenError)
  end

  describe "when passed a String" do
    it_behaves_like :kernel_remove_instance_variable, nil, "@greeting"
  end

  describe "when passed a Symbol" do
    it_behaves_like :kernel_remove_instance_variable, nil, :@greeting
  end

  describe "when passed an Object" do
    it "calls #to_str to convert the argument" do
      name = mock("kernel remove_instance_variable")
      name.should_receive(:to_str).and_return("@greeting")
      @instance.send :remove_instance_variable, name
    end
  end
end