A communication apparatus is configured to execute testing of whether or not the responding module is correctly responding to the plurality of commands transmitted and received between a transmission module and a reception module, the testing being performed via a loop-back mode transmission and reception path configured such that the reception module receives the command transmitted by the transmission module; and during the testing, following procedure is performed, which includes: transmitting the specific command by the transmission module; receiving the specific command by the reception module via the transmission and reception path; deactivating reception of the specific command; and transmitting a command different from the specific command subsequent to transmitting the specific command by the transmission module.