diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8248ed99..ad104328 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -161,6 +161,7 @@ set(INTERNAL_HEADERS
         ${HEADER_DIR}/internal/catch_objc_arc.hpp
         ${HEADER_DIR}/internal/catch_option.hpp
         ${HEADER_DIR}/internal/catch_platform.h
+        ${HEADER_DIR}/internal/catch_random_number_generator.h
         ${HEADER_DIR}/internal/catch_reenable_warnings.h
         ${HEADER_DIR}/internal/catch_reporter_registrars.hpp
         ${HEADER_DIR}/internal/catch_reporter_registry.hpp
@@ -218,6 +219,7 @@ set(IMPL_SOURCES
         ${HEADER_DIR}/internal/catch_notimplemented_exception.cpp
         ${HEADER_DIR}/internal/catch_registry_hub.cpp
         ${HEADER_DIR}/internal/catch_interfaces_reporter.cpp
+        ${HEADER_DIR}/internal/catch_random_number_generator.cpp
         ${HEADER_DIR}/internal/catch_result_type.cpp
         ${HEADER_DIR}/internal/catch_run_context.cpp
         ${HEADER_DIR}/internal/catch_section.cpp
diff --git a/include/catch_session.hpp b/include/catch_session.hpp
index f02b93d9..ed1a826a 100644
--- a/include/catch_session.hpp
+++ b/include/catch_session.hpp
@@ -17,6 +17,7 @@
 #include "internal/catch_test_spec.hpp"
 #include "internal/catch_version.h"
 #include "internal/catch_interfaces_reporter.h"
+#include "internal/catch_random_number_generator.h"
 #include "internal/catch_startup_exception_registry.h"
 #include "internal/catch_text.h"
 
diff --git a/include/internal/catch_common.cpp b/include/internal/catch_common.cpp
index 01c18ba4..9c18b543 100644
--- a/include/internal/catch_common.cpp
+++ b/include/internal/catch_common.cpp
@@ -29,14 +29,6 @@ namespace Catch {
         return line < other.line || ( line == other.line && (std::strcmp(file, other.file) < 0));
     }
 
-    void seedRng( IConfig const& config ) {
-        if( config.rngSeed() != 0 )
-            std::srand( config.rngSeed() );
-    }
-    unsigned int rngSeed() {
-        return getCurrentContext().getConfig()->rngSeed();
-    }
-
     std::ostream& operator << ( std::ostream& os, SourceLineInfo const& info ) {
 #ifndef __GNUG__
         os << info.file << '(' << info.line << ')';
diff --git a/include/internal/catch_common.h b/include/internal/catch_common.h
index fa04044a..dfc0258b 100644
--- a/include/internal/catch_common.h
+++ b/include/internal/catch_common.h
@@ -67,9 +67,6 @@ namespace Catch {
     bool alwaysTrue();
     bool alwaysFalse();
 
-    void seedRng( IConfig const& config );
-    unsigned int rngSeed();
-
     // Use this in variadic streaming macros to allow
     //    >> +StreamEndStop
     // as well as
diff --git a/include/internal/catch_random_number_generator.cpp b/include/internal/catch_random_number_generator.cpp
new file mode 100644
index 00000000..7149a58b
--- /dev/null
+++ b/include/internal/catch_random_number_generator.cpp
@@ -0,0 +1,31 @@
+/*
+ *  Created by Martin on 30/08/2017.
+ *
+ *  Distributed under the Boost Software License, Version 1.0. (See accompanying
+ *  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ */
+
+#include "catch_random_number_generator.h"
+#include "catch_context.h"
+#include "catch_interfaces_config.h"
+
+#include <cstdlib>
+
+namespace Catch {
+
+    void seedRng( IConfig const& config ) {
+        if( config.rngSeed() != 0 )
+            std::srand( config.rngSeed() );
+    }
+    unsigned int rngSeed() {
+        return getCurrentContext().getConfig()->rngSeed();
+    }
+
+    RandomNumberGenerator::result_type RandomNumberGenerator::operator()( result_type n ) const {
+        return std::rand() % n;
+    }
+    RandomNumberGenerator::result_type RandomNumberGenerator::operator()() const {
+        return std::rand() % max();
+    }
+
+}
diff --git a/include/internal/catch_random_number_generator.h b/include/internal/catch_random_number_generator.h
new file mode 100644
index 00000000..859e6cdf
--- /dev/null
+++ b/include/internal/catch_random_number_generator.h
@@ -0,0 +1,40 @@
+/*
+ *  Created by Martin on 30/08/2017.
+ *
+ *  Distributed under the Boost Software License, Version 1.0. (See accompanying
+ *  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ */
+#ifndef TWOBLUECUBES_CATCH_RANDOM_NUMBER_GENERATOR_H_INCLUDED
+#define TWOBLUECUBES_CATCH_RANDOM_NUMBER_GENERATOR_H_INCLUDED
+
+#include "catch_random_number_generator.h"
+
+#include <algorithm>
+
+namespace Catch {
+
+    struct IConfig;
+
+    void seedRng( IConfig const& config );
+
+    unsigned int rngSeed();
+
+    struct RandomNumberGenerator {
+        using result_type = std::ptrdiff_t;
+
+        static constexpr result_type min() { return 0; }
+        static constexpr result_type max() { return 1000000; }
+
+        result_type operator()( result_type n ) const;
+        result_type operator()() const;
+
+        template<typename V>
+        static void shuffle( V& vector ) {
+            RandomNumberGenerator rng;
+            std::shuffle( vector.begin(), vector.end(), rng );
+        }
+    };
+
+}
+
+#endif // TWOBLUECUBES_CATCH_RANDOM_NUMBER_GENERATOR_H_INCLUDED
diff --git a/include/internal/catch_run_context.cpp b/include/internal/catch_run_context.cpp
index 5d640e48..8b22398c 100644
--- a/include/internal/catch_run_context.cpp
+++ b/include/internal/catch_run_context.cpp
@@ -1,6 +1,7 @@
 #include "catch_run_context.hpp"
 #include "catch_context.h"
 #include "catch_enforce.h"
+#include "catch_random_number_generator.h"
 #include "catch_stream.h"
 
 #include <cassert>
diff --git a/include/internal/catch_test_case_registry_impl.cpp b/include/internal/catch_test_case_registry_impl.cpp
index 0bf0000f..85385a9c 100644
--- a/include/internal/catch_test_case_registry_impl.cpp
+++ b/include/internal/catch_test_case_registry_impl.cpp
@@ -10,6 +10,7 @@
 #include "catch_context.h"
 #include "catch_enforce.h"
 #include "catch_interfaces_registry_hub.h"
+#include "catch_random_number_generator.h"
 #include "catch_string_manip.h"
 #include "catch_test_case_info.h"
 
@@ -17,9 +18,6 @@
 
 namespace Catch {
 
-    RandomNumberGenerator::result_type RandomNumberGenerator::operator()( result_type n ) const { return std::rand() % n; }
-    RandomNumberGenerator::result_type RandomNumberGenerator::operator()() const { return std::rand() % max(); }
-
     std::vector<TestCase> sortTests( IConfig const& config, std::vector<TestCase> const& unsortedTestCases ) {
 
         std::vector<TestCase> sorted = unsortedTestCases;
diff --git a/include/internal/catch_test_case_registry_impl.hpp b/include/internal/catch_test_case_registry_impl.hpp
index ee412d9e..f49ad970 100644
--- a/include/internal/catch_test_case_registry_impl.hpp
+++ b/include/internal/catch_test_case_registry_impl.hpp
@@ -22,21 +22,6 @@ namespace Catch {
     class TestCase;
     struct IConfig;
 
-    struct RandomNumberGenerator {
-        using result_type = std::ptrdiff_t;
-
-        result_type operator()( result_type n ) const;
-
-        static constexpr result_type min() { return 0; }
-        static constexpr result_type max() { return 1000000; }
-        result_type operator()() const;
-        template<typename V>
-        static void shuffle( V& vector ) {
-            RandomNumberGenerator rng;
-            std::shuffle( vector.begin(), vector.end(), rng );
-        }
-    };
-
     std::vector<TestCase> sortTests( IConfig const& config, std::vector<TestCase> const& unsortedTestCases ); 
     bool matchTest( TestCase const& testCase, TestSpec const& testSpec, IConfig const& config );