NAME
    Test::LectroTest - Easy, automatic, specification-based tests

SYNOPSIS
        #!/usr/bin/perl -w

        use MyModule;  # contains code we want to test
        use Test::LectroTest;

        Property {
            ##[ x <- Int, y <- Int ]##
            MyModule::my_function( $x, $y ) >= 0;
        }, name => "my_function output is non-negative" ;

        Property { ... }, name => "yet another property" ;

        # more properties to check here

DESCRIPTION
    This module provides a simple (yet full featured) interface to
    LectroTest, an automated, specification-based testing system for Perl.
    To use it, you declare properties that specify the expected behavior of
    your software. LectroTest then checks your software to see whether those
    properties hold.

    You declare properties using the "Property" function, which takes a
    block of code and promotes it to a Test::LectroTest::Property:

        Property {
            ##[ x <- Int, y <- Int ]##
            MyModule::my_function( $x, $y ) >= 0;
        }, name => "my_function output is non-negative" ;

    The first part of the block must contain a generator-binding
    declaration. For example:

            ##[  x <- Int, y <- Int  ]##

    (Note the special bracketing, which is required.) This particular
    binding says, "For all integers *x* and *y*." (By the way, you aren't
    limited to integers. LectroTest also gives you booleans, strings, lists,
    hashes, and more, and it lets you define your own generator types. See
    Test::LectroTest::Generator for more.)

    The second part of the block is simply a snippet of code that makes use
    of the variables we bound earlier to test whether a property holds for
    the piece of software we are testing:

            MyModule::my_function( $x, $y ) >= 0;

    In this case, it asserts that "MyModule::my_function($x,$y)" returns a
    non-negative result. (Yes, $x and $y refer to the same *x* and *y* that
    we bound to the generators earlier. LectroTest automagically loads these
    lexically bound Perl variables with values behind the scenes.)

    Finally, we give the whole Property a name, in this case "my_function
    output is non-negative." It's a good idea to use a meaningful name
    because LectroTest refers to properties by name in its output.

    Let's take a look at the finished property specification:

        Property {
            ##[ x <- Int, y <- Int ]##
            MyModule::my_function( $x, $y ) >= 0;
        }, name => "my_function output is non-negative" ;

    It says, "For all integers *x* and *y*, we assert that my_function's
    output is non-negative."

    To check whether this property holds, simply put it in a Perl program
    that uses the Test::LectroTest module. (See the "SYNOPSIS" for an
    example.) When you run the program, LectroTest will load the property
    (and any others in the file) and check it by running random trials
    against the software you're testing.

    If LectroTest is able to "break" your software during the property
    check, it will emit a counterexample to your property's assertions and
    stop. You can plug the counterexample back into your software to debug
    the problem. (You might also want to add the counterexample to a list of
    regression tests.)

    A successful LectroTest looks like this:

      1..1
      ok 1 - 'my_function output is non-negative' (1000 attempts)

    On the other hand, if you're not so lucky:

      1..1
      not ok 1 - 'my_function output is non-negative' falsified \
          in 324 attempts
      # Counterexample:
      # $x = -34
      # $y = 0

ADJUSTING THE TESTING PARAMETERS
    There is one testing parameter that you may wish to change: The number
    of trials to run against each property checked. By default it is 1,000.
    If you want to try more or fewer trials, pass the "trials=>"*N* flag:

      use Test::LectroTest trials => 10_000;

CAVEATS
    When you use this module, it imports all of the generator-building
    functions from Test::LectroTest::Generator into the your code's
    namespace. This is almost always what you want, but I figured I ought to
    say something about it here to reduce the possibility of surprise.

    A Property specification must appear in the first column, i.e., without
    any indentation, in order for it to be automatically loaded and checked.
    If this poses a problem, let me know, and this restriction can be
    lifted.

SEE ALSO
    For a gentle introduction to LectroTest, see Test::LectroTest::Tutorial.
    Also, the slides from my LectroTest talk for the Pittsburgh Perl Mongers
    make for a great introduction. Download a copy from the LectroTest home
    (see below).

    Test::LectroTest::Property explains in detail what you can put inside of
    your property specifications.

    Test::LectroTest::Generator describes the many generators and generator
    combinators that you can use to define the test or condition space that
    you want LectroTest to search for bugs.

    Test::LectroTest::TestRunner describes the objects that check your
    properties and tells you how to turn their control knobs. You'll want to
    look here if you're interested in customizing the testing procedure.

LECTROTEST HOME
    The LectroTest home is http://community.moertel.com/LectroTest. There
    you will find more documentation, presentations, a wiki, and other
    helpful LectroTest-related resources. It's also the best place to ask
    questions.

AUTHOR
    Tom Moertel (tom@moertel.com)

INSPIRATION
    The LectroTest project was inspired by Haskell's fabulous QuickCheck
    module by Koen Claessen and John Hughes:
    http://www.cs.chalmers.se/~rjmh/QuickCheck/.

COPYRIGHT and LICENSE
    Copyright (c) 2004-05 by Thomas G Moertel. All rights reserved.

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

