Perl Test Tutorial: Replace The Untestable Part

<< Isolate The Untestable Part | Forcing Failure >>

Replace The Untestable Part

Then, Replace The Untestable Part

{
my @snooze_args = ();
my $snooze_called = 0;
local *Power::Manager::snooze = sub {
$snooze_called++;
@snooze_args = @_; # trap the arguments
return 0; # simulate successful system call
};

should_i_sleep($Min_Power - 1);
is( $snooze_called, 1, 'snooze called once' );
is( @snooze_args, 0, ' called properly' );
}

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Check that it was called.

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Check that it got the right arguments

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By changing the return value to non-zero we can simulate a

failure.

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Very, very powerful technique.