From: Eric Hodel <drbrain@...7.net>
Date: 2007-10-15T05:56:19+09:00
Subject: Re: Testing - Network Layer Fault Injection in Ruby

On Oct 14, 2007, at 13:23 , James Tucker wrote:
> I've yet to find something that fills this hole in my test cases.
> Does anyone do this, and if so, what tools do they use?

I do some of this with custom stubs in memcache-client, see below.   
I've also simulated call failures (Errno::whatever) with slightly  
more powerful stubs that can take a block to raise the exception.

Here's a fake socket:

class FakeSocket

   attr_reader :written, :data

   def initialize
     @written = StringIO.new
     @data = StringIO.new
   end

   def write(data)
     @written.write data
   end

   def gets
     @data.gets
   end

   def read(arg)
     @data.read arg
   end

end

And here's a test using it:

   def test_flush_all_failure
     socket = FakeSocket.new
     socket.data.write "ERROR\r\n"
     socket.data.rewind
     server = FakeServer.new socket
     def server.host() "localhost"; end
     def server.port() 11211; end

     @cache.servers = []
     @cache.servers << server

     assert_raise MemCache::MemCacheError do
       @cache.flush_all
     end

     assert_equal "flush_all\r\n", socket.written.string
   end


--
Poor workers blame their tools. Good workers build better tools. The
best workers get their tools to do the work for them. -- Syndicate Wars