无法在服务模块测试中模拟 httparty 请求

Question

我正在尝试在我的 HotelsApiService 模块上测试方法“get_all_hotels”：

BASE_URI = ENV['HOTELS_API_URI']

def get_all_hotels
    begin
        RequestService.new(BASE_URI).get("/hotels")
    rescue
        "Unable to get service response"
    end
end

但不能使测试通过这一点。显然问题是当我想模拟 RequestService 的调用时（RequestService 是一个使用 HTTParty 执行 http 请求的类）。

这是测试文件：

require "rails_helper"

describe HotelsApiService do
  let(:base_uri) { "base_uri" }
  let(:request_service) { double }

  subject { Object.new.extend HotelsApiService }

  before do
    allow(ENV).to receive(:[]).with('HOTELS_API_URI') { base_uri }        
  end

  describe "#get_all_hotels" do
    let(:api_response) {
      { hotel: { id: 1, name: "Hotel name", address: "Str 34", star_rating: 3, accomodation_type: "hotel" }}
}

    before do
      allow(RequestService).to receive(:new).with(base_uri) { request_service }
      allow(request_service).to receive(:get).with("/hotels") { api_response }
    end

    it 'responds with hotel' do
      expect(subject.get_all_hotels).to eq(api_response.to_json)
    end

  end
end

这样测试返回以下错误：

Failure/Error: expect(subject.get_all_hotels).to be_a_kind_of(Hotel)
   #<RequestService (class)> received :new with unexpected arguments
     expected: ("base_uri")
          got: (nil)
   Diff:
   @@ -1,2 +1,2 @@
   -["base_uri"]
   +[nil]

    Please stub a default value first if message might be received with other args as well.

如果我尝试以其他方式模拟它：

before do
  allow(RequestService).to receive_message_chain(:new, :edit).with(base_uri, "/hotels") { request_service }
end

我收到另一个错误：

Failure/Error: expect(subject.get_all_hotels).to eq(api_response.to_json)
   #<Double (anonymous)> received unexpected message :get with ("/hotels")

提前致谢

Answer 1

BASE_URI 是在您的源文件加载时设置的，这是在您模拟 ENV 以返回您期望的值之前。因此它等于 nil 并导致您的问题。