perl-Test-LectroTest

Easy, automatic, specification-based tests

This module provides a simple (yet full featured) interface to LectroTest, an automated, specification-based testing system for Perl. To use it, declare properties that specify the expected behavior of your software. LectroTest then checks your software to see whether those properties hold. Declare properties using the 'Property' function, which takes a block of code and promotes it to a Test::LectroTest::Property: Property { 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: (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.) *Note:* If you want to use testing assertions like 'ok' from Test::Simple or 'is', 'like', or 'cmp_ok' from Test::More (and the related family of Test::Builder-based testing modules), see Test::LectroTest::Compat, which lets you mix and match LectroTest with these modules. 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 { 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. *Note:* If you want to place LectroTest property checks into a test plan managed by Test::Builder-based modules such as Test::Simple or Test::More, see Test::LectroTest::Compat. 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