catch2/examples/300-Gen-OwnGenerator.cpp
Martin Jeřábek cde3509664 Fix various useful clang-tidy warnings
* bugprone-branch-clone
* bugprone-copy-constructor-init
* bugprone-empty-catch
* bugprone-sizeof-expression
* bugprone-switch-missing-default-case
* bugprone-unused-local-non-trivial-variable
* clang-analyzer-core.uninitialized.Assign
* clang-analyzer-cplusplus.Move
* clang-analyzer-optin.cplusplus.VirtualCall
* modernize-loop-convert
* modernize-raw-string-literal
* modernize-use-equals-default
* modernize-use-override
* modernize-use-using
* performance-avoid-endl
* performance-inefficient-string-concatenation
* performance-inefficient-vector-operation
* performance-noexcept-move-constructor
* performance-unnecessary-value-param (and improve generator example)
* readability-duplicate-include
* readability-inconsistent-declaration-parameter-name
* readability-non-const-parameter
* readability-redundant-casting
* readability-redundant-member-init
* readability-redundant-smartptr-get
* readability-static-accessed-through-instance
* unused variable in amalgamted tests
2024-03-01 21:24:45 +01:00

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// 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 final : 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