require 'stack'

context "A new stack" do
  setup do
    @stack = Stack.new
  end

  specify "should be empty" do
    @stack.should_be_empty
  end
end

context "An empty stack" do
  setup do
    @stack = Stack.new
  end

  specify "should keep its mouth shut when you send it 'push'" do
    lambda { @stack.push Object.new }.should.not.raise
  end
end
  
context "A stack with one item" do
  setup do
    @stack = Stack.new
    @stack.push "one item"
  end

  specify "should not be empty" do
    @stack.should_not_be_empty
  end

  specify "should return top when you send it 'top'" do
    @stack.top.should_equal "one item"
  end
  
  specify "should not be empty after 'top'" do
    @stack.top
    @stack.should_not_be_empty
  end
end