Test::MockObject not showing args when mocking a sub

jvector has asked for the wisdom of the Perl Monks concerning the following question:

Monks, again I commit the sin of Not Understanding It.

I am working with code that talks to a serial port.

    $port = new Device::SerialPort("/dev$opt_p");
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followed by

write_chunk ("modem control stuff");
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where

sub write_chunk {
    (my $count) = $port->write($_[0]);
}
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so to test it I put

if ($TESTING) {
    use Test::MockObject;
    $port = Test::MockObject->new();
    $port->mock ('write',
                 sub {my $arg=shift;print "wrote $arg to the serial po
+rt\n"} 
);
}
else {
    $port = new Device::SerialPort("/dev/$opt_p");
}
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So I would hope to see things like

wrote ATZ\r to the serial port

Instead I see

wrote Test::MockObject=HASH(0x885d760) to the serial port

The doc for Test::MockObject says

    * "mock(*name*, *coderef*)"
        Adds a coderef to the object. This allows code to call the nam
+ed
        method on the object. For example, this code:

            my $mock = Test::MockObject->new();
            $mock->mock( 'fluorinate',
                sub { 'impurifying precious bodily fluids' } );
            print $mock->fluorinate;

        will print a helpful warning message.
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Clearly I get a helpful message showing me that the sub has been called. But I infer that the sub I provide in the mock ('write', ...) statement does not get the arguments that are provided to the write.

Is there something I am missing?

Everybody knows signatures don't exist

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Replies are listed 'Best First'.
Re: Test::MockObject not showing args when mocking a sub by Anonymous Monk on May 27, 2009 at 14:19 UTC
`use Test::MockObject; my $mock = Test::MockObject->new(); $mock->mock( 'fluorinate', sub { use Data::Dumper; print Dumper( \@_ ); return 'impurifying precious bodily fluids'; } ); print $mock->fluorinate(1,2); __END__ $VAR1 = [ bless( {}, 'Test::MockObject' ), 1, 2 ]; impurifying precious bodily fluids` [download]	[reply] [d/l]
Re^2: Test::MockObject not showing args when mocking a sub by jvector (Friar) on May 27, 2009 at 14:45 UTC
OK, so the arg list in the mocked call gets a MockObject ref unshifted into the first position. Saying `$port->mock ('write', sub {my $Mock=shift;my $arg=shift;$arg=~s/\r/\n/g;print " +wrote $arg to the serial port\n";});` [download] gives `wrote ATE0 to the serial port wrote AT+CMGF=1 to the serial port wrote AT+CPIN=9532 to the serial port wrote ATI to the serial port` [download] Thank you! This signature will be ready by Christmas	[reply] [d/l] [select]