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Have the random generators use the global rng instance

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This means that if you nest multiple random generators inside one
test case, they will not return the same sequence of numbers.

Idea taken from #1736 by Amit Herman.

Closes #1736
Closes #1734
This commit is contained in:
Martin Hořeňovský 2019-10-07 20:24:37 +02:00
parent 535da5c513
commit a5a22cdadb
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GPG Key ID: DE48307B8B0D381A
2 changed files with 33 additions and 8 deletions
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14
include/internal/catch_generators_specific.hpp
View File

@ -10,6 +10,7 @@
#include "catch_context.h" #include "catch_context.h"
#include "catch_generators.hpp" #include "catch_generators.hpp"
#include "catch_interfaces_config.h" #include "catch_interfaces_config.h"
#include "catch_random_number_generator.h"
#include <random> #include <random>
@ -18,14 +19,13 @@ namespace Generators {
template <typename Float> template <typename Float>
class RandomFloatingGenerator final : public IGenerator<Float> { class RandomFloatingGenerator final : public IGenerator<Float> {
// FIXME: What is the right seed? Catch::SimplePcg32& m_rng;
std::minstd_rand m_rand;
std::uniform_real_distribution<Float> m_dist; std::uniform_real_distribution<Float> m_dist;
Float m_current_number; Float m_current_number;
public: public:
RandomFloatingGenerator(Float a, Float b): RandomFloatingGenerator(Float a, Float b):
m_rand(getCurrentContext().getConfig()->rngSeed()), m_rng(rng()),
m_dist(a, b) { m_dist(a, b) {
static_cast<void>(next()); static_cast<void>(next());
} }
@ -34,20 +34,20 @@ public:
return m_current_number; return m_current_number;
} }
bool next() override { bool next() override {
m_current_number = m_dist(m_rand); m_current_number = m_dist(m_rng);
return true; return true;
} }
}; };
template <typename Integer> template <typename Integer>
class RandomIntegerGenerator final : public IGenerator<Integer> { class RandomIntegerGenerator final : public IGenerator<Integer> {
std::minstd_rand m_rand; Catch::SimplePcg32& m_rng;
std::uniform_int_distribution<Integer> m_dist; std::uniform_int_distribution<Integer> m_dist;
Integer m_current_number; Integer m_current_number;
public: public:
RandomIntegerGenerator(Integer a, Integer b): RandomIntegerGenerator(Integer a, Integer b):
m_rand(getCurrentContext().getConfig()->rngSeed()), m_rng(rng()),
m_dist(a, b) { m_dist(a, b) {
static_cast<void>(next()); static_cast<void>(next());
} }
@ -56,7 +56,7 @@ public:
return m_current_number; return m_current_number;
} }
bool next() override { bool next() override {
m_current_number = m_dist(m_rand); m_current_number = m_dist(m_rng);
return true; return true;
} }
}; };

27
projects/SelfTest/IntrospectiveTests/GeneratorsImpl.tests.cpp
View File

@ -250,7 +250,7 @@ int const& TestGen::get() const {
} }
TEST_CASE("GENERATE capture macros", "[generators][internals][.approvals]") { TEST_CASE("GENERATE capture macros", "[generators][internals][approvals]") {
auto value = GENERATE(take(10, random(0, 10))); auto value = GENERATE(take(10, random(0, 10)));
non_copyable nc; nc.value = value; non_copyable nc; nc.value = value;
@ -258,3 +258,28 @@ TEST_CASE("GENERATE capture macros", "[generators][internals][.approvals]") {
auto value2 = GENERATE_REF(Catch::Generators::GeneratorWrapper<int>(std::unique_ptr<Catch::Generators::IGenerator<int>>(new TestGen(nc)))); auto value2 = GENERATE_REF(Catch::Generators::GeneratorWrapper<int>(std::unique_ptr<Catch::Generators::IGenerator<int>>(new TestGen(nc))));
REQUIRE(value == value2); REQUIRE(value == value2);
} }
TEST_CASE("Multiple random generators in one test case output different values", "[generators][internals][approvals]") {
SECTION("Integer") {
auto random1 = Catch::Generators::random(0, 1000);
auto random2 = Catch::Generators::random(0, 1000);
size_t same = 0;
for (size_t i = 0; i < 1000; ++i) {
same += random1.get() == random2.get();
random1.next(); random2.next();
}
// 0.5% seems like a sane bound for random identical elements within 1000 runs
REQUIRE(same < 5);
}
SECTION("Float") {
auto random1 = Catch::Generators::random(0., 1000.);
auto random2 = Catch::Generators::random(0., 1000.);
size_t same = 0;
for (size_t i = 0; i < 1000; ++i) {
same += random1.get() == random2.get();
random1.next(); random2.next();
}
// 0.5% seems like a sane bound for random identical elements within 1000 runs
REQUIRE(same < 5);
}
}