Mock Ruby: aws-sdk-s3 (example 2).rb

# From: https://aws.amazon.com/blogs/developer/advanced-client-stubbing-in-the-aws-sdk-for-ruby-version-3/

RSpec.describe RosterCsvNotifierJob, type: :job do
  it "s3 test example" do
    bucket = {
      "SeededKey" => { body: "Hello!" }
    }
    s3 = Aws::S3::Client.new(stub_responses: true)
    s3.stub_responses(:get_object, -> (context) {
      obj = bucket[context.params[:key]]
      if obj
        obj
      else
        'NoSuchKey'
      end
    })
    s3.stub_responses(:put_object, -> (context) {
      bucket[context.params[:key]] = { body: context.params[:body] }
      {}
    })
    begin
      s3.get_object(bucket: "test", key: "test")
    rescue Aws::S3::Errors::NoSuchKey
      s3.put_object(bucket: "test", key: "test", body: "DOES matter!")
    end
    # puts
    # puts "Read object from S3 ex1: #{s3.get_object(bucket: "test", key: "test").body.read}" #=> "DOES matter!"
    # puts "Read object from S3 ex1: #{s3.get_object(bucket: "test", key: "SeededKey").body.read}" #=> "Hello!"
    # puts
  end
  describe "Enhanced Stubbing Example Tests" do
    let(:fake_s3) { {} }
    let(:client) do
      client = Aws::S3::Client.new(stub_responses: true)
      client.stub_responses(
        :create_bucket, ->(context) {
          name = context.params[:bucket]
          if fake_s3[name]
            'BucketAlreadyExists' # standalone strings are treated as exceptions
          else
            fake_s3[name] = {}
            {}
          end
        }
      )
      client.stub_responses(
        :get_object, ->(context) {
          bucket = context.params[:bucket]
          key = context.params[:key]
          b_contents = fake_s3[bucket]
          if b_contents
            obj = b_contents[key]
            if obj
              { body: obj }
            else
              'NoSuchKey'
            end
          else
            'NoSuchBucket'
          end
        }
      )
      client.stub_responses(
        :put_object, ->(context) {
          bucket = context.params[:bucket]
          key = context.params[:key]
          body = context.params[:body]
          b_contents = fake_s3[bucket]
          if b_contents
            b_contents[key] = body
            {}
          else
            'NoSuchBucket'
          end
        }
      )
      client
    end

    it "raises an exception when a bucket is created twice" do
      client.create_bucket(bucket: "foo")
      client.create_bucket(bucket: "bar")
      expect {
        client.create_bucket(bucket: "foo")
      }.to raise_error(Aws::S3::Errors::BucketAlreadyExists)
      expect(client.api_requests.size).to eq(3)
    end

    context "bucket operations" do
      before do
        client.create_bucket(bucket: "test")
      end

      it "can write and retrieve an object" do
        client.put_object(bucket: "test", key: "obj", body: "Hello!")
        obj = client.get_object(bucket: "test", key: "obj")
        expect(obj.body.read).to eq("Hello!")
        expect(client.api_requests.size).to eq(3)
        expect(client.api_requests.last[:params]).to eq(
          bucket: "test",
          key: "obj"
        )
      end

      it "raises the appropriate exception when a bucket doesn't exist" do
        expect {
          client.put_object(
            bucket: "sirnotappearinginthistest",
            key: "knight_sayings",
            body: "Ni!"
          )
        }.to raise_error(Aws::S3::Errors::NoSuchBucket)
        expect(client.api_requests.size).to eq(2)
      end

      it "raises the appropriate exception when an object doesn't exist" do
        expect {
          client.get_object(bucket: "test", key: "404NoSuchKey")
        }.to raise_error(Aws::S3::Errors::NoSuchKey)
        expect(client.api_requests.size).to eq(2)
      end
    end
  end
end