Property Checking for Catch2

Header-only library for property checking in C++17 with the Catch2 unit testing framework. This library is inspire by the great Haskell testing library QuickCheck. It uses random-generated data which it feeds to unit tests in order to discover property/invariant violations.

It is best to start with an example:

#include <catch.hpp>
#include <pcc.hpp>

TEST_CASE( "pcc example" ) {
    pcc::run_test( []( int a, std::vector< float > b ) {
        // test, using Catch2 assertion macros
        // a and b will be randomly generated
        REQUIRE( a == 0 ); // this will fail
    } );
}

Here we see normal Catch2 test named "pcc example" which contains call to pcc's entry point run_test. run_test accepts a callable object (which must have non-overloaded call operator) and it generates random instances of arguments for this callable object. The number of tests and size of instances can be configured by passing pcc::config as a second argument (see source for pcc::config).

Main Features

• automatic generation of inputs based o type of the tested function/property
• shrinking of counterexamples – when test fails pcc will try to find smaller input on which the test also fails
• header only
• integrates with Catch2 – uses Catch2 assertions
• written for C++17, there will probably never be support for GCC < 7 and Clang < 5
• support for generators and shrinks for custom types

Known Limitations

• SECTIONS do not work inside run_test
• failures not from Catch2 macros will not result in shrinking of inputs
• shrinking is noisy – it shows intermediate results during shrinking
• many std data structures cannot be auto-generated yet