Currently, when asserting that a command succeeded, we just capture the
return code of the command. If that is not zero, the assertion fails,
but the error message is not very splicit:
AssertionError: 1 != 0
Replace the error message with an explicit message that dumps the failed
command, the error code, and the resulting output.
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>