77 lines
2.4 KiB
C++
77 lines
2.4 KiB
C++
|
|
// Copyright Catch2 Authors
|
|
// Distributed under the Boost Software License, Version 1.0.
|
|
// (See accompanying file LICENSE.txt or copy at
|
|
// https://www.boost.org/LICENSE_1_0.txt)
|
|
|
|
// SPDX-License-Identifier: BSL-1.0
|
|
|
|
// 300-Gen-OwnGenerator.cpp
|
|
// Shows how to define a custom generator.
|
|
|
|
// Specifically we will implement a random number generator for integers
|
|
// It will have infinite capacity and settable lower/upper bound
|
|
|
|
#include <catch2/catch_test_macros.hpp>
|
|
#include <catch2/generators/catch_generators.hpp>
|
|
#include <catch2/generators/catch_generators_adapters.hpp>
|
|
|
|
#include <random>
|
|
|
|
namespace {
|
|
|
|
// This class shows how to implement a simple generator for Catch tests
|
|
class RandomIntGenerator : public Catch::Generators::IGenerator<int> {
|
|
std::minstd_rand m_rand;
|
|
std::uniform_int_distribution<> m_dist;
|
|
int current_number;
|
|
public:
|
|
|
|
RandomIntGenerator(int low, int high):
|
|
m_rand(std::random_device{}()),
|
|
m_dist(low, high)
|
|
{
|
|
static_cast<void>(next());
|
|
}
|
|
|
|
int const& get() const override;
|
|
bool next() override {
|
|
current_number = m_dist(m_rand);
|
|
return true;
|
|
}
|
|
};
|
|
|
|
// Avoids -Wweak-vtables
|
|
int const& RandomIntGenerator::get() const {
|
|
return current_number;
|
|
}
|
|
|
|
// This helper function provides a nicer UX when instantiating the generator
|
|
// Notice that it returns an instance of GeneratorWrapper<int>, which
|
|
// is a value-wrapper around std::unique_ptr<IGenerator<int>>.
|
|
Catch::Generators::GeneratorWrapper<int> random(int low, int high) {
|
|
return Catch::Generators::GeneratorWrapper<int>(
|
|
new RandomIntGenerator(low, high)
|
|
// Another possibility:
|
|
// Catch::Detail::make_unique<RandomIntGenerator>(low, high)
|
|
);
|
|
}
|
|
|
|
} // end anonymous namespaces
|
|
|
|
// The two sections in this test case are equivalent, but the first one
|
|
// is much more readable/nicer to use
|
|
TEST_CASE("Generating random ints", "[example][generator]") {
|
|
SECTION("Nice UX") {
|
|
auto i = GENERATE(take(100, random(-100, 100)));
|
|
REQUIRE(i >= -100);
|
|
REQUIRE(i <= 100);
|
|
}
|
|
SECTION("Creating the random generator directly") {
|
|
auto i = GENERATE(take(100, GeneratorWrapper<int>(Catch::Detail::make_unique<RandomIntGenerator>(-100, 100))));
|
|
REQUIRE(i >= -100);
|
|
REQUIRE(i <= 100);
|
|
}
|
|
}
|
|
|
|
// Compiling and running this file will result in 400 successful assertions
|