v2.6.0v2.6.0

1 files changed, 611 insertions, 286 deletions

diff --git a/single_include/catch2/catch.hpp b/single_include/catch2/catch.hpp
index b1b2411d..cc3f97cb 100644
--- a/single_include/catch2/catch.hpp
+++ b/single_include/catch2/catch.hpp
@@ -1,9 +1,9 @@
 /*
- *  Catch v2.5.0
- *  Generated: 2018-11-26 20:46:12.165372
+ *  Catch v2.6.0
+ *  Generated: 2019-01-31 22:25:55.560884
  *  ----------------------------------------------------------
  *  This file has been merged from multiple headers. Please don't edit it directly
- *  Copyright (c) 2018 Two Blue Cubes Ltd. All rights reserved.
+ *  Copyright (c) 2019 Two Blue Cubes Ltd. All rights reserved.
  *
  *  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)
@@ -14,7 +14,7 @@
 
 
 #define CATCH_VERSION_MAJOR 2
-#define CATCH_VERSION_MINOR 5
+#define CATCH_VERSION_MINOR 6
 #define CATCH_VERSION_PATCH 0
 
 #ifdef __clang__
@@ -36,10 +36,11 @@
 #       pragma clang diagnostic ignored "-Wcovered-switch-default"
 #    endif
 #elif defined __GNUC__
-     // GCC likes to warn on REQUIREs, and we cannot suppress them
-     // locally because g++'s support for _Pragma is lacking in older,
-     // still supported, versions
-#    pragma GCC diagnostic ignored "-Wparentheses"
+     // Because REQUIREs trigger GCC's -Wparentheses, and because still
+     // supported version of g++ have only buggy support for _Pragmas,
+     // Wparentheses have to be suppressed globally.
+#    pragma GCC diagnostic ignored "-Wparentheses" // See #674 for details
+
 #    pragma GCC diagnostic push
 #    pragma GCC diagnostic ignored "-Wunused-variable"
 #    pragma GCC diagnostic ignored "-Wpadded"
@@ -274,6 +275,14 @@ namespace Catch {
 #endif
 
 ////////////////////////////////////////////////////////////////////////////////
+// Check if optional is available and usable
+#if defined(__has_include)
+#  if __has_include(<optional>) && defined(CATCH_CPP17_OR_GREATER)
+#    define CATCH_INTERNAL_CONFIG_CPP17_OPTIONAL
+#  endif // __has_include(<optional>) && defined(CATCH_CPP17_OR_GREATER)
+#endif // __has_include
+
+////////////////////////////////////////////////////////////////////////////////
 // Check if variant is available and usable
 #if defined(__has_include)
 #  if __has_include(<variant>) && defined(CATCH_CPP17_OR_GREATER)
@@ -283,9 +292,11 @@ namespace Catch {
 #      include <ciso646>
 #      if defined(__GLIBCXX__) && defined(_GLIBCXX_RELEASE) && (_GLIBCXX_RELEASE < 9)
 #        define CATCH_CONFIG_NO_CPP17_VARIANT
-#     else
+#      else
 #        define CATCH_INTERNAL_CONFIG_CPP17_VARIANT
 #      endif // defined(__GLIBCXX__) && defined(_GLIBCXX_RELEASE) && (_GLIBCXX_RELEASE < 9)
+#    else
+#      define CATCH_INTERNAL_CONFIG_CPP17_VARIANT
 #    endif // defined(__clang__) && (__clang_major__ < 8)
 #  endif // __has_include(<variant>) && defined(CATCH_CPP17_OR_GREATER)
 #endif // __has_include
@@ -309,6 +320,10 @@ namespace Catch {
 #    define CATCH_CONFIG_CPP11_TO_STRING
 #endif
 
+#if defined(CATCH_INTERNAL_CONFIG_CPP17_OPTIONAL) && !defined(CATCH_CONFIG_NO_CPP17_OPTIONAL) && !defined(CATCH_CONFIG_CPP17_OPTIONAL)
+#  define CATCH_CONFIG_CPP17_OPTIONAL
+#endif
+
 #if defined(CATCH_INTERNAL_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS) && !defined(CATCH_CONFIG_NO_CPP17_UNCAUGHT_EXCEPTIONS) && !defined(CATCH_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS)
 #  define CATCH_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS
 #endif
@@ -407,10 +422,10 @@ namespace Catch {
             line( _line )
         {}
 
-        SourceLineInfo( SourceLineInfo const& other )        = default;
-        SourceLineInfo( SourceLineInfo && )                  = default;
-        SourceLineInfo& operator = ( SourceLineInfo const& ) = default;
-        SourceLineInfo& operator = ( SourceLineInfo && )     = default;
+        SourceLineInfo( SourceLineInfo const& other )            = default;
+        SourceLineInfo& operator = ( SourceLineInfo const& )     = default;
+        SourceLineInfo( SourceLineInfo&& )              noexcept = default;
+        SourceLineInfo& operator = ( SourceLineInfo&& ) noexcept = default;
 
         bool empty() const noexcept;
         bool operator == ( SourceLineInfo const& other ) const noexcept;
@@ -463,7 +478,6 @@ namespace Catch {
 // start catch_interfaces_testcase.h
 
 #include <vector>
-#include <memory>
 
 namespace Catch {
 
@@ -474,8 +488,6 @@ namespace Catch {
         virtual ~ITestInvoker();
     };
 
-    using ITestCasePtr = std::shared_ptr<ITestInvoker>;
-
     class TestCase;
     struct IConfig;
 
@@ -500,8 +512,6 @@ namespace Catch {
 
 namespace Catch {
 
-    class StringData;
-
     /// A non-owning string class (similar to the forthcoming std::string_view)
     /// Note that, because a StringRef may be a substring of another string,
     /// it may not be null terminated. c_str() must return a null terminated
@@ -621,6 +631,8 @@ inline auto operator "" _catch_sr( char const* rawChars, std::size_t size ) noex
 // start catch_type_traits.hpp
 
 
+#include <type_traits>
+
 namespace Catch{
 
 #ifdef CATCH_CPP17_OR_GREATER
@@ -713,7 +725,85 @@ struct is_unique<T0, T1, Rest...> : std::integral_constant
 #define INTERNAL_CATCH_TEMPLATE_UNIQUE_NAME(Name, ...) INTERNAL_CATCH_TEMPLATE_UNIQUE_NAME1(Name, INTERNAL_CATCH_EXPAND_VARGS(INTERNAL_CATCH_REMOVE_PARENS(__VA_ARGS__)))
 #endif
 
+#define INTERNAL_CATCH_MAKE_TYPE_LIST(types) TypeList<INTERNAL_CATCH_REMOVE_PARENS(types)>
+
+#define INTERNAL_CATCH_MAKE_TYPE_LISTS_FROM_TYPES(types)\
+    CATCH_REC_LIST(INTERNAL_CATCH_MAKE_TYPE_LIST,INTERNAL_CATCH_REMOVE_PARENS(types))
+
 // end catch_preprocessor.hpp
+// start catch_meta.hpp
+
+
+#include <type_traits>
+
+template< typename... >
+struct TypeList{};
+
+template< typename... >
+struct append;
+
+template< template<typename...> class L1
+	, typename...E1
+	, template<typename...> class L2
+	, typename...E2
+	>
+struct append< L1<E1...>, L2<E2...> >
+{
+	using type = L1<E1..., E2...>;
+};
+
+template< template<typename...> class L1
+	, typename...E1
+	, template<typename...> class L2
+	, typename...E2
+	, typename...Rest
+	>
+struct append< L1<E1...>, L2<E2...>, Rest...>
+{
+	using type = typename append< L1<E1..., E2...>, Rest... >::type;
+};
+
+template< template<typename...> class
+        , typename...
+        >
+struct rewrap;
+
+template< template<typename...> class Container
+        , template<typename...> class List
+        , typename...elems
+        >
+struct rewrap<Container, List<elems...>>
+{
+    using type = TypeList< Container< elems... > >;
+};
+
+template< template<typename...> class Container
+        , template<typename...> class List
+        , class...Elems
+        , typename...Elements>
+struct rewrap<Container, List<Elems...>, Elements...>
+{
+    using type = typename append<TypeList<Container<Elems...>>, typename rewrap<Container, Elements...>::type>::type;
+};
+
+template< template<typename...> class...Containers >
+struct combine
+{
+    template< typename...Types >
+    struct with_types
+    {
+        template< template <typename...> class Final >
+        struct into
+        {
+            using type = typename append<Final<>, typename rewrap<Containers, Types...>::type...>::type;
+        };
+    };
+};
+
+template<typename T>
+struct always_false : std::false_type {};
+
+// end catch_meta.hpp
 namespace Catch {
 
 template<typename C>
@@ -849,6 +939,38 @@ struct AutoReg : NonCopyable {
             return 0;\
         }();
 
+    #define INTERNAL_CATCH_TEMPLATE_PRODUCT_TEST_CASE2(TestName, TestFuncName, Name, Tags, TmplTypes, TypesList) \
+        CATCH_INTERNAL_SUPPRESS_GLOBALS_WARNINGS                      \
+        template<typename TestType> static void TestFuncName();       \
+        namespace {                                                   \
+            template<typename... Types>                               \
+            struct TestName {                                         \
+                TestName() {                                          \
+                    CATCH_INTERNAL_CHECK_UNIQUE_TYPES(Types...)       \
+                    int index = 0;                                    \
+                    using expander = int[];                           \
+                    (void)expander{(Catch::AutoReg( Catch::makeTestInvoker( &TestFuncName<Types> ), CATCH_INTERNAL_LINEINFO, Catch::StringRef(), Catch::NameAndTags{ Name " - " + Catch::StringMaker<int>::convert(index++), Tags } ), 0)... };/* NOLINT */ \
+                }                                                     \
+            };                                                        \
+            static int INTERNAL_CATCH_UNIQUE_NAME( globalRegistrar ) = [](){ \
+                using TestInit = combine<INTERNAL_CATCH_REMOVE_PARENS(TmplTypes)> \
+                            ::with_types<INTERNAL_CATCH_MAKE_TYPE_LISTS_FROM_TYPES(TypesList)>::into<TestName>::type; \
+                TestInit();                                           \
+                return 0;                                             \
+            }();                                                      \
+        }                                                             \
+        CATCH_INTERNAL_UNSUPPRESS_GLOBALS_WARNINGS                    \
+        template<typename TestType>                                   \
+        static void TestFuncName()
+
+#ifndef CATCH_CONFIG_TRADITIONAL_MSVC_PREPROCESSOR
+    #define INTERNAL_CATCH_TEMPLATE_PRODUCT_TEST_CASE(Name, Tags, ...)\
+        INTERNAL_CATCH_TEMPLATE_PRODUCT_TEST_CASE2(INTERNAL_CATCH_UNIQUE_NAME( ____C_A_T_C_H____T_E_M_P_L_A_T_E____T_E_S_T____ ), INTERNAL_CATCH_UNIQUE_NAME( ____C_A_T_C_H____T_E_M_P_L_A_T_E____T_E_S_T____F_U_N_C____ ),Name,Tags,__VA_ARGS__)
+#else
+    #define INTERNAL_CATCH_TEMPLATE_PRODUCT_TEST_CASE(Name, Tags, ...)\
+        INTERNAL_CATCH_EXPAND_VARGS( INTERNAL_CATCH_TEMPLATE_PRODUCT_TEST_CASE2( INTERNAL_CATCH_UNIQUE_NAME( ____C_A_T_C_H____T_E_M_P_L_A_T_E____T_E_S_T____ ), INTERNAL_CATCH_UNIQUE_NAME( ____C_A_T_C_H____T_E_M_P_L_A_T_E____T_E_S_T____F_U_N_C____ ), Name, Tags, __VA_ARGS__ ) )
+#endif
+
     #define INTERNAL_CATCH_TEMPLATE_TEST_CASE_METHOD_2( TestNameClass, TestName, ClassName, Name, Tags, ... ) \
         CATCH_INTERNAL_SUPPRESS_GLOBALS_WARNINGS \
         namespace{ \
@@ -879,6 +1001,41 @@ struct AutoReg : NonCopyable {
         INTERNAL_CATCH_EXPAND_VARGS( INTERNAL_CATCH_TEMPLATE_TEST_CASE_METHOD_2( INTERNAL_CATCH_UNIQUE_NAME( ____C_A_T_C_H____T_E_M_P_L_A_T_E____T_E_S_T____C_L_A_S_S____ ), INTERNAL_CATCH_UNIQUE_NAME( ____C_A_T_C_H____T_E_M_P_L_A_T_E____T_E_S_T____ ) , ClassName, Name, Tags, __VA_ARGS__ ) )
 #endif
 
+    #define INTERNAL_CATCH_TEMPLATE_PRODUCT_TEST_CASE_METHOD_2(TestNameClass, TestName, ClassName, Name, Tags, TmplTypes, TypesList)\
+        CATCH_INTERNAL_SUPPRESS_GLOBALS_WARNINGS \
+        template<typename TestType> \
+            struct TestName : INTERNAL_CATCH_REMOVE_PARENS(ClassName <TestType>) { \
+                void test();\
+            };\
+        namespace {\
+            template<typename...Types>\
+            struct TestNameClass{\
+                TestNameClass(){\
+                    CATCH_INTERNAL_CHECK_UNIQUE_TYPES(Types...)\
+                    int index = 0;\
+                    using expander = int[];\
+                    (void)expander{(Catch::AutoReg( Catch::makeTestInvoker( &TestName<Types>::test ), CATCH_INTERNAL_LINEINFO, #ClassName, Catch::NameAndTags{ Name " - " + Catch::StringMaker<int>::convert(index++), Tags } ), 0)... };/* NOLINT */ \
+                }\
+            };\
+            static int INTERNAL_CATCH_UNIQUE_NAME( globalRegistrar ) = [](){\
+                using TestInit = combine<INTERNAL_CATCH_REMOVE_PARENS(TmplTypes)>\
+                            ::with_types<INTERNAL_CATCH_MAKE_TYPE_LISTS_FROM_TYPES(TypesList)>::into<TestNameClass>::type;\
+                TestInit();\
+                return 0;\
+            }(); \
+        }\
+        CATCH_INTERNAL_UNSUPPRESS_GLOBALS_WARNINGS \
+        template<typename TestType> \
+        void TestName<TestType>::test()
+
+#ifndef CATCH_CONFIG_TRADITIONAL_MSVC_PREPROCESSOR
+    #define INTERNAL_CATCH_TEMPLATE_PRODUCT_TEST_CASE_METHOD( ClassName, Name, Tags, ... )\
+        INTERNAL_CATCH_TEMPLATE_PRODUCT_TEST_CASE_METHOD_2( INTERNAL_CATCH_UNIQUE_NAME( ____C_A_T_C_H____T_E_M_P_L_A_T_E____T_E_S_T____ ), INTERNAL_CATCH_UNIQUE_NAME( ____C_A_T_C_H____T_E_M_P_L_A_T_E____T_E_S_T____F_U_N_C____ ), ClassName, Name, Tags, __VA_ARGS__ )
+#else
+    #define INTERNAL_CATCH_TEMPLATE_PRODUCT_TEST_CASE_METHOD( ClassName, Name, Tags, ... )\
+        INTERNAL_CATCH_EXPAND_VARGS( INTERNAL_CATCH_TEMPLATE_PRODUCT_TEST_CASE_METHOD_2( INTERNAL_CATCH_UNIQUE_NAME( ____C_A_T_C_H____T_E_M_P_L_A_T_E____T_E_S_T____ ), INTERNAL_CATCH_UNIQUE_NAME( ____C_A_T_C_H____T_E_M_P_L_A_T_E____T_E_S_T____F_U_N_C____ ), ClassName, Name, Tags, __VA_ARGS__ ) )
+#endif
+
 // end catch_test_registry.h
 // start catch_capture.hpp
 
@@ -1370,6 +1527,7 @@ namespace Catch {
 #  define CATCH_CONFIG_ENABLE_TUPLE_STRINGMAKER
 #  define CATCH_CONFIG_ENABLE_VARIANT_STRINGMAKER
 #  define CATCH_CONFIG_ENABLE_CHRONO_STRINGMAKER
+#  define CATCH_CONFIG_ENABLE_OPTIONAL_STRINGMAKER
 #endif
 
 // Separate std::pair specialization
@@ -1391,6 +1549,24 @@ namespace Catch {
 }
 #endif // CATCH_CONFIG_ENABLE_PAIR_STRINGMAKER
 
+#if defined(CATCH_CONFIG_ENABLE_OPTIONAL_STRINGMAKER) && defined(CATCH_CONFIG_CPP17_OPTIONAL)
+#include <optional>
+namespace Catch {
+    template<typename T>
+    struct StringMaker<std::optional<T> > {
+        static std::string convert(const std::optional<T>& optional) {
+            ReusableStringStream rss;
+            if (optional.has_value()) {
+                rss << ::Catch::Detail::stringify(*optional);
+            } else {
+                rss << "{ }";
+            }
+            return rss.str();
+        }
+    };
+}
+#endif // CATCH_CONFIG_ENABLE_OPTIONAL_STRINGMAKER
+
 // Separate std::tuple specialization
 #if defined(CATCH_CONFIG_ENABLE_TUPLE_STRINGMAKER)
 #include <tuple>
@@ -1652,6 +1828,7 @@ struct ratio_string<std::milli> {
 #pragma warning(disable:4018) // more "signed/unsigned mismatch"
 #pragma warning(disable:4312) // Converting int to T* using reinterpret_cast (issue on x64 platform)
 #pragma warning(disable:4180) // qualifier applied to function type has no meaning
+#pragma warning(disable:4800) // Forcing result to true or false
 #endif
 
 namespace Catch {
@@ -1695,6 +1872,62 @@ namespace Catch {
             m_op( op ),
             m_rhs( rhs )
         {}
+
+        template<typename T>
+        auto operator && ( T ) const -> BinaryExpr<LhsT, RhsT const&> const {
+            static_assert(always_false<T>::value,
+            "chained comparisons are not supported inside assertions, "
+            "wrap the expression inside parentheses, or decompose it");
+        }
+
+        template<typename T>
+        auto operator || ( T ) const -> BinaryExpr<LhsT, RhsT const&> const {
+            static_assert(always_false<T>::value,
+            "chained comparisons are not supported inside assertions, "
+            "wrap the expression inside parentheses, or decompose it");
+        }
+
+        template<typename T>
+        auto operator == ( T ) const -> BinaryExpr<LhsT, RhsT const&> const {
+            static_assert(always_false<T>::value,
+            "chained comparisons are not supported inside assertions, "
+            "wrap the expression inside parentheses, or decompose it");
+        }
+
+        template<typename T>
+        auto operator != ( T ) const -> BinaryExpr<LhsT, RhsT const&> const {
+            static_assert(always_false<T>::value,
+            "chained comparisons are not supported inside assertions, "
+            "wrap the expression inside parentheses, or decompose it");
+        }
+
+        template<typename T>
+        auto operator > ( T ) const -> BinaryExpr<LhsT, RhsT const&> const {
+            static_assert(always_false<T>::value,
+            "chained comparisons are not supported inside assertions, "
+            "wrap the expression inside parentheses, or decompose it");
+        }
+
+        template<typename T>
+        auto operator < ( T ) const -> BinaryExpr<LhsT, RhsT const&> const {
+            static_assert(always_false<T>::value,
+            "chained comparisons are not supported inside assertions, "
+            "wrap the expression inside parentheses, or decompose it");
+        }
+
+        template<typename T>
+        auto operator >= ( T ) const -> BinaryExpr<LhsT, RhsT const&> const {
+            static_assert(always_false<T>::value,
+            "chained comparisons are not supported inside assertions, "
+            "wrap the expression inside parentheses, or decompose it");
+        }
+
+        template<typename T>
+        auto operator <= ( T ) const -> BinaryExpr<LhsT, RhsT const&> const {
+            static_assert(always_false<T>::value,
+            "chained comparisons are not supported inside assertions, "
+            "wrap the expression inside parentheses, or decompose it");
+        }
     };
 
     template<typename LhsT>
@@ -1707,7 +1940,7 @@ namespace Catch {
 
     public:
         explicit UnaryExpr( LhsT lhs )
-        :   ITransientExpression{ false, lhs ? true : false },
+        :   ITransientExpression{ false, static_cast<bool>(lhs) },
             m_lhs( lhs )
         {}
     };
@@ -1774,6 +2007,20 @@ namespace Catch {
             return { static_cast<bool>(m_lhs <= rhs), m_lhs, "<=", rhs };
         }
 
+        template<typename RhsT>
+        auto operator && ( RhsT const& ) -> BinaryExpr<LhsT, RhsT const&> const {
+            static_assert(always_false<RhsT>::value,
+            "operator&& is not supported inside assertions, "
+            "wrap the expression inside parentheses, or decompose it");
+        }
+
+        template<typename RhsT>
+        auto operator || ( RhsT const& ) -> BinaryExpr<LhsT, RhsT const&> const {
+            static_assert(always_false<RhsT>::value,
+            "operator|| is not supported inside assertions, "
+            "wrap the expression inside parentheses, or decompose it");
+        }
+
         auto makeUnaryExpr() const -> UnaryExpr<LhsT> {
             return UnaryExpr<LhsT>{ m_lhs };
         }
@@ -3175,16 +3422,17 @@ namespace Catch {
 namespace Catch {
 
     namespace Generators {
-        class GeneratorBase {
-        protected:
-            size_t m_size = 0;
-
+        class GeneratorUntypedBase {
         public:
-            GeneratorBase( size_t size ) : m_size( size ) {}
-            virtual ~GeneratorBase();
-            auto size() const -> size_t { return m_size; }
+            GeneratorUntypedBase() = default;
+            virtual ~GeneratorUntypedBase();
+            // Attempts to move the generator to the next element
+             //
+             // Returns true iff the move succeeded (and a valid element
+             // can be retrieved).
+            virtual bool next() = 0;
         };
-        using GeneratorBasePtr = std::unique_ptr<GeneratorBase>;
+        using GeneratorBasePtr = std::unique_ptr<GeneratorUntypedBase>;
 
     } // namespace Generators
 
@@ -3193,7 +3441,6 @@ namespace Catch {
         virtual auto hasGenerator() const -> bool = 0;
         virtual auto getGenerator() const -> Generators::GeneratorBasePtr const& = 0;
         virtual void setGenerator( Generators::GeneratorBasePtr&& generator ) = 0;
-        virtual auto getIndex() const -> std::size_t = 0;
     };
 
 } // namespace Catch
@@ -3233,8 +3480,21 @@ namespace Catch {
 #include <cassert>
 
 #include <utility>
+#include <exception>
 
 namespace Catch {
+
+class GeneratorException : public std::exception {
+    const char* const m_msg = "";
+
+public:
+    GeneratorException(const char* msg):
+        m_msg(msg)
+    {}
+
+    const char* what() const noexcept override final;
+};
+
 namespace Generators {
 
     // !TBD move this into its own location?
@@ -3246,197 +3506,308 @@ namespace Generators {
     }
 
     template<typename T>
-    struct IGenerator {
-        virtual ~IGenerator() {}
-        virtual auto get( size_t index ) const -> T = 0;
+    struct IGenerator : GeneratorUntypedBase {
+        virtual ~IGenerator() = default;
+
+        // Returns the current element of the generator
+        //
+        // \Precondition The generator is either freshly constructed,
+        // or the last call to `next()` returned true
+        virtual T const& get() const = 0;
+        using type = T;
     };
 
     template<typename T>
-    class SingleValueGenerator : public IGenerator<T> {
+    class SingleValueGenerator final : public IGenerator<T> {
         T m_value;
     public:
-        SingleValueGenerator( T const& value ) : m_value( value ) {}
+        SingleValueGenerator(T const& value) : m_value( value ) {}
+        SingleValueGenerator(T&& value) : m_value(std::move(value)) {}
 
-        auto get( size_t ) const -> T override {
+        T const& get() const override {
             return m_value;
         }
+        bool next() override {
+            return false;
+        }
     };
 
     template<typename T>
-    class FixedValuesGenerator : public IGenerator<T> {
+    class FixedValuesGenerator final : public IGenerator<T> {
         std::vector<T> m_values;
-
+        size_t m_idx = 0;
     public:
         FixedValuesGenerator( std::initializer_list<T> values ) : m_values( values ) {}
 
-        auto get( size_t index ) const -> T override {
-            return m_values[index];
+        T const& get() const override {
+            return m_values[m_idx];
         }
-    };
-
-    template<typename T>
-    class RangeGenerator : public IGenerator<T> {
-        T const m_first;
-        T const m_last;
-
-    public:
-        RangeGenerator( T const& first, T const& last ) : m_first( first ), m_last( last ) {
-            assert( m_last > m_first );
-        }
-
-        auto get( size_t index ) const -> T override {
-            // ToDo:: introduce a safe cast to catch potential overflows
-            return static_cast<T>(m_first+index);
+        bool next() override {
+            ++m_idx;
+            return m_idx < m_values.size();
         }
     };
 
-    template<typename T>
-    struct NullGenerator : IGenerator<T> {
-        auto get( size_t ) const -> T override {
-            CATCH_INTERNAL_ERROR("A Null Generator is always empty");
-        }
-    };
-
-    template<typename T>
-    class Generator {
+    template <typename T>
+    class GeneratorWrapper final {
         std::unique_ptr<IGenerator<T>> m_generator;
-        size_t m_size;
-
     public:
-        Generator( size_t size, std::unique_ptr<IGenerator<T>> generator )
-        :   m_generator( std::move( generator ) ),
-            m_size( size )
+        GeneratorWrapper(std::unique_ptr<IGenerator<T>> generator):
+            m_generator(std::move(generator))
         {}
-
-        auto size() const -> size_t { return m_size; }
-        auto operator[]( size_t index ) const -> T {
-            assert( index < m_size );
-            return m_generator->get( index );
+        T const& get() const {
+            return m_generator->get();
+        }
+        bool next() {
+            return m_generator->next();
         }
     };
 
-    std::vector<size_t> randomiseIndices( size_t selectionSize, size_t sourceSize );
+    template <typename T>
+    GeneratorWrapper<T> value(T&& value) {
+        return GeneratorWrapper<T>(pf::make_unique<SingleValueGenerator<T>>(std::forward<T>(value)));
+    }
+    template <typename T>
+    GeneratorWrapper<T> values(std::initializer_list<T> values) {
+        return GeneratorWrapper<T>(pf::make_unique<FixedValuesGenerator<T>>(values));
+    }
 
     template<typename T>
-    class GeneratorRandomiser : public IGenerator<T> {
-        Generator<T> m_baseGenerator;
+    class Generators : public IGenerator<T> {
+        std::vector<GeneratorWrapper<T>> m_generators;
+        size_t m_current = 0;
 
-        std::vector<size_t> m_indices;
-    public:
-        GeneratorRandomiser( Generator<T>&& baseGenerator, size_t numberOfItems )
-        :   m_baseGenerator( std::move( baseGenerator ) ),
-            m_indices( randomiseIndices( numberOfItems, m_baseGenerator.size() ) )
-        {}
-
-        auto get( size_t index ) const -> T override {
-            return m_baseGenerator[m_indices[index]];
+        void populate(GeneratorWrapper<T>&& generator) {
+            m_generators.emplace_back(std::move(generator));
+        }
+        void populate(T&& val) {
+            m_generators.emplace_back(value(std::move(val)));
+        }
+        template<typename U>
+        void populate(U&& val) {
+            populate(T(std::move(val)));
+        }
+        template<typename U, typename... Gs>
+        void populate(U&& valueOrGenerator, Gs... moreGenerators) {
+            populate(std::forward<U>(valueOrGenerator));
+            populate(std::forward<Gs>(moreGenerators)...);
         }
-    };
 
-    template<typename T>
-    struct RequiresASpecialisationFor;
+    public:
+        template <typename... Gs>
+        Generators(Gs... moreGenerators) {
+            m_generators.reserve(sizeof...(Gs));
+            populate(std::forward<Gs>(moreGenerators)...);
+        }
 
-    template<typename T>
-    auto all() -> Generator<T> { return RequiresASpecialisationFor<T>(); }
+        T const& get() const override {
+            return m_generators[m_current].get();
+        }
 
-    template<>
-    auto all<int>() -> Generator<int>;
+        bool next() override {
+            if (m_current >= m_generators.size()) {
+                return false;
+            }
+            const bool current_status = m_generators[m_current].next();
+            if (!current_status) {
+                ++m_current;
+            }
+            return m_current < m_generators.size();
+        }
+    };
 
-    template<typename T>
-    auto range( T const& first, T const& last ) -> Generator<T> {
-        return Generator<T>( (last-first), pf::make_unique<RangeGenerator<T>>( first, last ) );
+    template<typename... Ts>
+    GeneratorWrapper<std::tuple<Ts...>> table( std::initializer_list<std::tuple<typename std::decay<Ts>::type...>> tuples ) {
+        return values<std::tuple<Ts...>>( tuples );
     }
 
-    template<typename T>
-    auto random( T const& first, T const& last ) -> Generator<T> {
-        auto gen = range( first, last );
-        auto size = gen.size();
+    // Tag type to signal that a generator sequence should convert arguments to a specific type
+    template <typename T>
+    struct as {};
 
-        return Generator<T>( size, pf::make_unique<GeneratorRandomiser<T>>( std::move( gen ), size ) );
+    template<typename T, typename... Gs>
+    auto makeGenerators( GeneratorWrapper<T>&& generator, Gs... moreGenerators ) -> Generators<T> {
+        return Generators<T>(std::move(generator), std::forward<Gs>(moreGenerators)...);
     }
     template<typename T>
-    auto random( size_t size ) -> Generator<T> {
-        return Generator<T>( size, pf::make_unique<GeneratorRandomiser<T>>( all<T>(), size ) );
+    auto makeGenerators( GeneratorWrapper<T>&& generator ) -> Generators<T> {
+        return Generators<T>(std::move(generator));
     }
-
-    template<typename T>
-    auto values( std::initializer_list<T> values ) -> Generator<T> {
-        return Generator<T>( values.size(), pf::make_unique<FixedValuesGenerator<T>>( values ) );
-    }
-    template<typename T>
-    auto value( T const& val ) -> Generator<T> {
-        return Generator<T>( 1, pf::make_unique<SingleValueGenerator<T>>( val ) );
+    template<typename T, typename... Gs>
+    auto makeGenerators( T&& val, Gs... moreGenerators ) -> Generators<T> {
+        return makeGenerators( value( std::forward<T>( val ) ), std::forward<Gs>( moreGenerators )... );
     }
-
-    template<typename T>
-    auto as() -> Generator<T> {
-        return Generator<T>( 0, pf::make_unique<NullGenerator<T>>() );
+    template<typename T, typename U, typename... Gs>
+    auto makeGenerators( as<T>, U&& val, Gs... moreGenerators ) -> Generators<T> {
+        return makeGenerators( value( T( std::forward<U>( val ) ) ), std::forward<Gs>( moreGenerators )... );
     }
 
-    template<typename... Ts>
-    auto table( std::initializer_list<std::tuple<Ts...>>&& tuples ) -> Generator<std::tuple<Ts...>> {
-        return values<std::tuple<Ts...>>( std::forward<std::initializer_list<std::tuple<Ts...>>>( tuples ) );
-    }
+    template <typename T>
+    class TakeGenerator : public IGenerator<T> {
+        GeneratorWrapper<T> m_generator;
+        size_t m_returned = 0;
+        size_t m_target;
+    public:
+        TakeGenerator(size_t target, GeneratorWrapper<T>&& generator):
+            m_generator(std::move(generator)),
+            m_target(target)
+        {
+            assert(target != 0 && "Empty generators are not allowed");
+        }
+        T const& get() const override {
+            return m_generator.get();
+        }
+        bool next() override {
+            ++m_returned;
+            if (m_returned >= m_target) {
+                return false;
+            }
 
-    template<typename T>
-    struct Generators : GeneratorBase {
-        std::vector<Generator<T>> m_generators;
+            const auto success = m_generator.next();
+            // If the underlying generator does not contain enough values
+            // then we cut short as well
+            if (!success) {
+                m_returned = m_target;
+            }
+            return success;
+        }
+    };
 
-        using type = T;
+    template <typename T>
+    GeneratorWrapper<T> take(size_t target, GeneratorWrapper<T>&& generator) {
+        return GeneratorWrapper<T>(pf::make_unique<TakeGenerator<T>>(target, std::move(generator)));
+    }
 
-        Generators() : GeneratorBase( 0 ) {}
+    template <typename T, typename Predicate>
+    class FilterGenerator : public IGenerator<T> {
+        GeneratorWrapper<T> m_generator;
+        Predicate m_predicate;
+    public:
+        template <typename P = Predicate>
+        FilterGenerator(P&& pred, GeneratorWrapper<T>&& generator):
+            m_generator(std::move(generator)),
+            m_predicate(std::forward<P>(pred))
+        {
+            if (!m_predicate(m_generator.get())) {
+                // It might happen that there are no values that pass the
+                // filter. In that case we throw an exception.
+                auto has_initial_value = next();
+                if (!has_initial_value) {
+                    Catch::throw_exception(GeneratorException("No valid value found in filtered generator"));
+                }
+            }
+        }
 
-        void populate( T&& val ) {
-            m_size += 1;
-            m_generators.emplace_back( value( std::move( val ) ) );
+        T const& get() const override {
+            return m_generator.get();
         }
-        template<typename U>
-        void populate( U&& val ) {
-            populate( T( std::move( val ) ) );
+
+        bool next() override {
+            bool success = m_generator.next();
+            if (!success) {
+                return false;
+            }
+            while (!m_predicate(m_generator.get()) && (success = m_generator.next()) == true);
+            return success;
         }
-        void populate( Generator<T>&& generator ) {
-            m_size += generator.size();
-            m_generators.emplace_back( std::move( generator ) );
+    };
+
+    template <typename T, typename Predicate>
+    GeneratorWrapper<T> filter(Predicate&& pred, GeneratorWrapper<T>&& generator) {
+        return GeneratorWrapper<T>(std::unique_ptr<IGenerator<T>>(pf::make_unique<FilterGenerator<T, Predicate>>(std::forward<Predicate>(pred), std::move(generator))));
+    }
+
+    template <typename T>
+    class RepeatGenerator : public IGenerator<T> {
+        GeneratorWrapper<T> m_generator;
+        mutable std::vector<T> m_returned;
+        size_t m_target_repeats;
+        size_t m_current_repeat = 0;
+        size_t m_repeat_index = 0;
+    public:
+        RepeatGenerator(size_t repeats, GeneratorWrapper<T>&& generator):
+            m_generator(std::move(generator)),
+            m_target_repeats(repeats)
+        {
+            assert(m_target_repeats > 0 && "Repeat generator must repeat at least once");
         }
 
-        template<typename U, typename... Gs>
-        void populate( U&& valueOrGenerator, Gs... moreGenerators ) {
-            populate( std::forward<U>( valueOrGenerator ) );
-            populate( std::forward<Gs>( moreGenerators )... );
+        T const& get() const override {
+            if (m_current_repeat == 0) {
+                m_returned.push_back(m_generator.get());
+                return m_returned.back();
+            }
+            return m_returned[m_repeat_index];
         }
 
-        auto operator[]( size_t index ) const -> T {
-            size_t sizes = 0;
-            for( auto const& gen : m_generators ) {
-                auto localIndex = index-sizes;
-                sizes += gen.size();
-                if( index < sizes )
-                    return gen[localIndex];
+        bool next() override {
+            // There are 2 basic cases:
+            // 1) We are still reading the generator
+            // 2) We are reading our own cache
+
+            // In the first case, we need to poke the underlying generator.
+            // If it happily moves, we are left in that state, otherwise it is time to start reading from our cache
+            if (m_current_repeat == 0) {
+                const auto success = m_generator.next();
+                if (!success) {
+                    ++m_current_repeat;
+                }
+                return m_current_repeat < m_target_repeats;
+            }
+
+            // In the second case, we need to move indices forward and check that we haven't run up against the end
+            ++m_repeat_index;
+            if (m_repeat_index == m_returned.size()) {
+                m_repeat_index = 0;
+                ++m_current_repeat;
             }
-            CATCH_INTERNAL_ERROR("Index '" << index << "' is out of range (" << sizes << ')');
+            return m_current_repeat < m_target_repeats;
         }
     };
 
-    template<typename T, typename... Gs>
-    auto makeGenerators( Generator<T>&& generator, Gs... moreGenerators ) -> Generators<T> {
-        Generators<T> generators;
-        generators.m_generators.reserve( 1+sizeof...(Gs) );
-        generators.populate( std::move( generator ), std::forward<Gs>(