Add specs for addresses:assign command.
user
```ruby
require File.expand_path(File.dirname(__FILE__) + '/../../../spec_helper')

describe "addresses:assign command" do
  def cli
    @cli ||= HP::Cloud::CLI.new
  end

  before(:all) do
    @hp_svc = compute_connection
    response, exit = run_command('addresses:add').stdout_and_exit_status
    @public_ip = response.scan(/'([^']+)/)[0][0]
    response2 = @hp_svc.run_instances('ami-00000005', 1, 1, {'InstanceType' => 'm1.small'})
    @new_server_id = response2.body['instancesSet'][0]['instanceId']
  end

  context "when specifying a bad IP address" do
    before(:all) do
      @response, @exit = run_command('addresses:assign 111.111.111.111 11111').stderr_and_exit_status
    end

    it "should show error message" do
      @response.should eql("You don't have an address with public IP '111.111.111.111', use `hpcloud addresses:add` to create one.\n")
    end
    its_exit_status_should_be(:not_found)
  end
  context "when specifying a bad server id" do
    before(:all) do
      @response, @exit = run_command("addresses:assign #{@public_ip} 11111").stderr_and_exit_status
    end

    it "should show error message" do
      @response.should eql("You don't have a server with id '11111'.\n")
    end
    its_exit_status_should_be(:not_found)
  end
  context "when specifying a good IP address and server id" do
    before(:all) do
      @response, @exit = run_command("addresses:assign #{@public_ip} #{@new_server_id}").stdout_and_exit_status
    end

    it "should show success message" do
      @response.should eql("Assigned address '#{@public_ip}' to server with id '#{@new_server_id}'.\n")
    end
    its_exit_status_should_be(:success)
  end

  after(:all) do
    address = @hp_svc.addresses.select {|a| a.public_ip == @public_ip}.first
    address.destroy if address
    server = get_server(@hp_svc, @new_server_id)
    server.destroy if server
  end

end```
assistant