Ruby rspec 推入阵列时出错

Question

Im trying to pass a test for pushing an item into an array from another class. Here is the method.

require_relative 'message'

class Test

  attr_reader :message

  def initialize(message = Message.new)
    @message = message
  end

  def push(hello)
    @message.array << hello
  end
end

The empty array in a different class.

class Message

  attr_reader :array 

  def initialize
    @array = []
  end
end

and my test.

require 'test'

describe Test do

  let(:message) { double(array: [])}

  describe '#push' do
    it 'pushes an item into an array from the message class' do
      subject.push("hello")
      expect(message.array).to eq ["hello"]
    end
  end
end

currenty getting the error

expected: ["hello"]
     got: []

       (compared using ==)

what am i doing wrong? The method itself is simple and works, why does my test not?

Answer 1

The message you defined here: let(:message) { double(array: [])} has nothing to do with the rest.

Since you pushed into subject you have to check on it.

require 'test'

describe Test do
  describe '#push' do
    it 'pushes an item into an array from the message class' do
      subject = Test.new
      subject.push("hello")
      expect(subject.message.array).to eq ["hello"]
    end
  end
end

Answer 2

In your let, you assign an empty array to message and then test if it contains 'hello'. That fails because message is empty. Did you mean to push 'hello' to the message array instead of to 'subject'?