Terry, I had the same problem with that failing test_httpservers.test_invalid_request using the latest build on Windows. 
After debugging, I found out that the problem was caused by my antivirus solution. Its http scanning engine caught malformed http requests, like the one in the test ("gEt / hTTP/1.0\r\nhost: 127.0.0.1:50340\r\nAccept-Encoding: identity\r\n\r\n"; for instance) and it modified the first line by uppercasing it, thus making the perfect condition for a failing test.