1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
// 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
|
