ruby - 我应该如何测试我为 Socket 编写的包装器？

Question

因此，作为这个 Source Engine 项目的一部分，我编写了一个基本上是套接字包装器的类。我想对它进行单元测试（它最终会成为我在完成后发布的 gem，所以应该对其进行测试）

问题是......我对单元测试非常陌生，我真的不知道我应该如何测试这个东西。

相关代码在这里： https ://github.com/misutowolf/freeman/blob/master/lib/source_socket.rb

Answer 1

首先，我会说当意外的参数进入构造函数时，您可能应该引发异常。假设您要返回异常，那么对于此类而言，测试实际上非常简单。这应该让你开始：

# spec/lib/source_socket_spec.rb

describe SourceSocket do

  subject { source_socket }

  let(:source_socket) { SourceSocket.new(address, port, buffer) }

  let(:address) { double :address, class: SourceAddress, ip:   '1.2.3.4' }
  let(:port)    { double :port,    class: SourcePort,    num:  9876      }
  let(:buffer)  { double :buffer,  class: SourceBuffer                   }

  describe '#new' do
    context 'when the arguments are of the correct types' do
      it 'assigns the expected variables' do
        subject
        assigns(:address).should eq '1.2.3.4'
        assigns(:buffer).should  eq buffer
        assigns(:port).should    eq 9876
      end
    end

    context 'when the arguments are of incorrect types' do
      context 'when the address is of incorrect type' do
        let(:address) { double :address }
        expect { subject }.to raise_error('Error: Address argument is wrong type.')
      end

      context 'when the port is of incorrect type' do
        let(:port)    { double :port    }
        expect { subject }.to raise_error('Error: Port argument is wrong type.')
      end

      context 'when the buffer is of incorrect type' do
        let(:buffer)  { double :buffer  }
        expect { subject }.to raise_error('Error: Buffer must be a SourceBuffer object!')
      end
    end
  end

  describe '#to_s' do
    its(:to_s) { should eq '1.2.3.4:9876' }
  end

  describe '#open' do
    subject { source_socket.open(engine) }
    let(:engine) { double(:engine) }

    let(:socket) { double(:socket, connect: nil) }
    let(:packed) { double(:packed) }

    before do
      Socket.stub(:new).and_return(socket)
      Socket.stub(:pack_sockaddr_in).and_return(packed)
    end

    it 'assigns the engine variable' do
      subject
      assigns(:engine).should_not be_nil
    end

    it 'instantiates a Socket' do
      Socket.should_receive(:new).with(Socket::PF_INET, Socket::SOCK_DGRAM)
      subject
    end

    it 'assigns the socket variable' do
      subject
      assigns(:socket).should_not be_nil
    end

    it 'packs up the port and host' do
      Socket.should_receive(:pack_sockaddr_in).with(9876, '1.2.3.4')
      subject
    end

    it 'connects the socket' do
      socket.should_receive(:connect).with(packed)
    end
  end
end

请记住，有很多测试方法，而RSpec 文档是您最好的朋友。