クラスのモックを作る時(Aws::EC2::Resource を例に)

test_spec.rb

require "aws-sdk"

RSpec.describe "Test" do
  it "test" do
    allow(Aws::EC2::Resource).to receive(:new).and_return("Aws1") # ①
    allow(Aws::EC2::Resource).to receive(:new).with(region: "ap-northeast-1").and_return("Aws2") # ②
    allow(Aws::EC2::Resource).to receive(:new).with(hash_including(region: "ap-northeast-2")).and_return("Aws3") # ③

    ec2 = Aws::EC2::Resource.new
    pp ec2 # => "Aws1", 引数が無いので①に該当

    ec2 = Aws::EC2::Resource.new(region: "us-east-1")
    pp ec2 # => "Aws1", 引数がどれにも合致しないので①に該当

    ec2 = Aws::EC2::Resource.new(region: "ap-northeast-1")
    pp ec2 # => "Aws2", 引数が完全に合致するので②に該当

    ec2 = Aws::EC2::Resource.new(stub_responses: true, region: "ap-northeast-1")
    pp ec2 # => "Aws1", 引数がどれにも合致しないので①に該当、②は `hash_including` ではなく完全一致でないとハマらない

    ec2 = Aws::EC2::Resource.new(region: "ap-northeast-2")
    pp ec2 # => "Aws3", 引数が③に完全合致

    ec2 = Aws::EC2::Resource.new(stub_responses: true, region: "ap-northeast-2")
    pp ec2 # => "Aws3", 引数が③に合致、 余計なstub_responses があるけど hash_including だから合致される
  end
end