The problem is that ok() is tied to the Test::Builder testing and reporting harness and LectroTest uses a different underlying harness because of all the trials it does. (Maybe I should investigate integration?)

Anyway, if you want to use Test::Builder-based modules for their testing features and not for their harness features (which is the case when you are using them inside of LectroTest properties), you can (hackishly) redefine Test::Builder's ok() method to simply return the result status without doing anything else.

Using Test::More for the example:

    use warnings;
    use strict;

    use Test::More;
    use Test::LectroTest;

    {
        no warnings;
        sub Test::Builder::ok { $_[1] ? 1 : 0 }  # redefine ok()
    }

    Property {
        ##[ x <- Int( range=>[0,10] ) ]##
        cmp_ok( $x, '>=', 0, "" );
    }, name => "cmp_ok() works with LectroTest";
[download]

Testing it out:

    $ perl pm-lectrotest-testbuilder.pl
    1..1
    ok 1 - 'cmp_ok() works with LectroTest' (1000 attempts)
[download]

I hope that this helps.

Cheers,
Tom