Make the user-facing random Generators reproducible

Thanks to the new distributions, this is almost trivial change.

2 files changed, 52 insertions, 14 deletions

diff --git a/src/catch2/generators/catch_generators_random.cpp b/src/catch2/generators/catch_generators_random.cpp
index 2e3390fd..00a8e634 100644
--- a/src/catch2/generators/catch_generators_random.cpp
+++ b/src/catch2/generators/catch_generators_random.cpp
@@ -7,7 +7,35 @@
 // SPDX-License-Identifier: BSL-1.0
 
 #include <catch2/generators/catch_generators_random.hpp>
-
 #include <catch2/internal/catch_context.hpp>
 
-std::uint32_t Catch::Generators::Detail::getSeed() { return sharedRng()(); }
+#include <random>
+
+namespace Catch {
+    namespace Generators {
+        namespace Detail {
+            std::uint32_t getSeed() { return sharedRng()(); }
+        } // namespace Detail
+
+        struct RandomFloatingGenerator<long double>::PImpl {
+            PImpl( long double a, long double b, uint32_t seed ):
+                rng( seed ), dist( a, b ) {}
+
+            Catch::SimplePcg32 rng;
+            std::uniform_real_distribution<long double> dist;
+        };
+
+        RandomFloatingGenerator<long double>::RandomFloatingGenerator(
+            long double a, long double b, std::uint32_t seed) :
+            m_pimpl(Catch::Detail::make_unique<PImpl>(a, b, seed)) {
+            static_cast<void>( next() );
+        }
+
+        RandomFloatingGenerator<long double>::~RandomFloatingGenerator() =
+            default;
+        bool RandomFloatingGenerator<long double>::next() {
+            m_current_number = m_pimpl->dist( m_pimpl->rng );
+            return true;
+        }
+    } // namespace Generators
+} // namespace Catch
diff --git a/src/catch2/generators/catch_generators_random.hpp b/src/catch2/generators/catch_generators_random.hpp
index bcd4888d..d5f307d4 100644
--- a/src/catch2/generators/catch_generators_random.hpp
+++ b/src/catch2/generators/catch_generators_random.hpp
@@ -11,8 +11,9 @@
 #include <catch2/internal/catch_context.hpp>
 #include <catch2/generators/catch_generators.hpp>
 #include <catch2/internal/catch_random_number_generator.hpp>
-
-#include <random>
+#include <catch2/internal/catch_uniform_integer_distribution.hpp>
+#include <catch2/internal/catch_uniform_floating_point_distribution.hpp>
+#include <catch2/internal/catch_unique_ptr.hpp>
 
 namespace Catch {
 namespace Generators {
@@ -26,7 +27,7 @@ namespace Detail {
 template <typename Float>
 class RandomFloatingGenerator final : public IGenerator<Float> {
     Catch::SimplePcg32 m_rng;
-    std::uniform_real_distribution<Float> m_dist;
+    Catch::uniform_floating_point_distribution<Float> m_dist;
     Float m_current_number;
 public:
     RandomFloatingGenerator( Float a, Float b, std::uint32_t seed ):
@@ -44,10 +45,27 @@ public:
     }
 };
 
+template <>
+class RandomFloatingGenerator<long double> final : public IGenerator<long double> {
+    // We still rely on <random> for this specialization, but we don't
+    // want to drag it into the header.
+    struct PImpl;
+    Catch::Detail::unique_ptr<PImpl> m_pimpl;
+    long double m_current_number;
+
+public:
+    RandomFloatingGenerator( long double a, long double b, std::uint32_t seed );
+
+    long double const& get() const override { return m_current_number; }
+    bool next() override;
+
+    ~RandomFloatingGenerator() override; // = default
+};
+
 template <typename Integer>
 class RandomIntegerGenerator final : public IGenerator<Integer> {
     Catch::SimplePcg32 m_rng;
-    std::uniform_int_distribution<Integer> m_dist;
+    Catch::uniform_integer_distribution<Integer> m_dist;
     Integer m_current_number;
 public:
     RandomIntegerGenerator( Integer a, Integer b, std::uint32_t seed ):
@@ -68,14 +86,6 @@ public:
 template <typename T>
 std::enable_if_t<std::is_integral<T>::value, GeneratorWrapper<T>>
 random(T a, T b) {
-    static_assert(
-        !std::is_same<T, char>::value &&
-        !std::is_same<T, int8_t>::value &&
-        !std::is_same<T, uint8_t>::value &&
-        !std::is_same<T, signed char>::value &&
-        !std::is_same<T, unsigned char>::value &&
-        !std::is_same<T, bool>::value,
-        "The requested type is not supported by the underlying random distributions from std" );
     return GeneratorWrapper<T>(
         Catch::Detail::make_unique<RandomIntegerGenerator<T>>(a, b, Detail::getSeed())
     );