Adds a test that verifies extra body content beyond the content-length is ignored provided that the checksum value matches that of the content-length bytes. Add comment to explain why this is the case. Drive-by: add clarifying comment to unit test. Change-Id: I8f198298a817be47223e2f45fbc48a6f393b3bef Signed-off-by: Alistair Coles <alistairncoles@gmail.com>