More About Test Harness and Failure Modes

Remote call susceptible failures

Consider building a test harness that substitutes for the remote end of every web service call. Because the remote call uses the network, the socket connection is susceptible to the following failures:

• It can be refused.

• It can sit in a listen queue until the caller times out.

• The remote end can reply with a SYN/ACK and then never send any data.

• The remote end can send nothing but RESET packets.

• The remote end can report a full receive window and never drain the data.

• The connection can be established, but the remote end never sends a byte of data.

• The connection can be established, but packets could be lost, causing retransmit delays.

• The connection can be established, but the remote end never acknowledges receiving a packet, causing endless retransmits.

• The service can accept a request, send response headers (supposing HTTP), and never send the response body.

• The service can send one byte of the response every thirty ...