Starting out Alepha from scratch, as a C++17 effort.

This one is going to be prepped for GitHub private, from the get
go.  This initial commit has some evaluation helpers and the
unit testing infrastructure.  `TableTest` will come next.

Testing/test.h

@@ -0,0 +1,165 @@
+static_assert( __cplusplus > 201700, "C++17 Required" );
+
+#pragma once
+
+#include <Alepha/Alepha.h>
+
+#include <cassert>
+
+#include <iostream>
+#include <string>
+#include <utility>
+#include <vector>
+#include <functional>
+#include <memory>
+
+namespace Alepha::Hydrogen::Testing
+{
+	inline namespace exports { inline namespace testing {} }
+
+	namespace detail::testing
+	{
+		inline namespace exports {}
+
+		using namespace std::literals::string_literals;
+
+		namespace C
+		{
+			const std::string csi= "\e[";
+			const std::string green= C::csi + "32m";
+			const std::string red= C::csi + "31m";
+			const std::string normal= C::csi + "0m";
+		}
+
+		struct TestName
+		{
+			std::string name;
+			bool disabled= false;
+
+			[[nodiscard]] TestName
+			operator -() const
+			{
+				auto rv= *this;
+
+				rv.disabled= true;
+
+				return rv;
+			}
+		};
+
+		namespace exports
+		{
+			struct TestFailureException;
+
+			inline namespace literals
+			{
+				[[nodiscard]] inline auto
+				operator""_test( const char name[], std::size_t amount )
+				{
+					return TestName{ std::string{ name, name + amount } };
+				}
+			}
+		}
+
+		inline auto &
+		registry()
+		{
+			static std::vector< std::tuple< std::string, bool, std::function< void() > > > registry;
+			return registry;
+		}
+
+		// It is okay to discard this, if making tests in an enroll block.
+		inline auto
+		operator <= ( TestName name, std::function< void () > test )
+		{
+			struct TestRegistration {} rv;
+
+			registry().emplace_back( name.name, name.disabled, test );
+			assert( not registry().empty() );
+			assert( std::get< 1 >( registry().back() ) == name.disabled );
+
+			return rv;
+		};
+
+		struct exports::TestFailureException
+		{
+			int failureCount= -1;
+		};
+
+		inline auto
+		operator <= ( TestName name, std::function< int () > test )
+		{
+			auto wrapper= [test]
+			{
+				const int failures= test();
+				if( failures > 0 ) throw TestFailureException{ failures };
+			};
+
+			return name <= wrapper;
+		}
+
+		template< typename TestFunc >
+		inline auto
+		operator <= ( TestName name, TestFunc test )
+		{
+			return name <= std::function{ test };
+		}
+
+		namespace exports
+		{
+			[[nodiscard]] inline int
+			runAllTests( const std::vector< std::string > selections= {} )
+			{
+				bool failed= false;
+				const auto selected= [ selections ]( const std::string test )
+				{
+					for( const auto &selection: selections )
+					{
+						if( test.find( selection ) != std::string::npos ) return true;
+					}
+					return empty( selections );
+				};
+
+				const auto explicitlyNamed= [ selections ]( const std::string s )
+				{
+					return std::find( begin( selections ), end( selections ), s ) != end( selections );
+				};
+
+				for( const auto &[ name, disabled, test ]: registry() )
+				try
+				{
+					if( explicitlyNamed( name ) or not disabled and selected( name ) )
+					{
+						test();
+						std::cout << C::green << "SUCCESS" << C::normal << ": " << name << std::endl;
+					}
+				}
+				catch( ... )
+				{
+					try
+					{
+						failed= true;
+						std::cout << C::red << "FAILURE" << C::normal << ": " << name;
+						throw;
+					}
+					catch( const TestFailureException &fail ) { std::cout << " -- " <<  fail.failureCount << " failures."; }
+					catch( ... ) { std::cout << " --  unknown failure count"; }
+					std::cout << std::endl;
+				}
+				
+				return failed ? EXIT_FAILURE : EXIT_SUCCESS;
+			}
+
+			[[nodiscard]] inline int
+			runAllTests( const unsigned argcnt, const char *const *const argvec )
+			{
+				return runAllTests( { argvec + 1, argvec + argcnt } );
+			}
+		}
+	}
+
+	namespace exports::testing
+	{
+		using namespace detail::testing::exports;
+	}
+}