From 6e45126f53dc9e060eb0cb0bdfcf0b705873abc2 Mon Sep 17 00:00:00 2001
From: Michele Caini <michele.caini@gmail.com>
Date: Wed, 15 Jul 2020 15:38:13 +0200
Subject: [PATCH] test: added explicit test for ENTT_NO_ETO

---
 src/entt/config/config.h             |  2 +-
 src/entt/entity/storage.hpp          |  2 +-
 test/CMakeLists.txt                  | 17 +++++++----------
 test/entt/entity/registry_no_eto.cpp | 25 +++++++++++++++++++++++++
 4 files changed, 34 insertions(+), 12 deletions(-)
 create mode 100644 test/entt/entity/registry_no_eto.cpp

diff --git a/src/entt/config/config.h b/src/entt/config/config.h
index aef92b78c..960c128e9 100644
--- a/src/entt/config/config.h
+++ b/src/entt/config/config.h
@@ -48,7 +48,7 @@
 #else
 #   include <type_traits>
 #   // sfinae-friendly definition
-#   define ENTT_IS_EMPTY(Type) (false && std::is_empty_v<Type>)
+#   define ENTT_IS_EMPTY(Type) (std::is_empty_v<Type>, false)
 #endif
 
 
diff --git a/src/entt/entity/storage.hpp b/src/entt/entity/storage.hpp
index 750264a56..d1ff22240 100644
--- a/src/entt/entity/storage.hpp
+++ b/src/entt/entity/storage.hpp
@@ -478,7 +478,7 @@ private:
 /*! @copydoc storage */
 template<typename Entity, typename Type>
 // the useless decltype(...) helps to get around a quite impressive issue of VS2017
-class storage<Entity, Type, decltype(std::enable_if_t<ENTT_IS_EMPTY(Type)>())>: public sparse_set<Entity> {
+class storage<Entity, Type, std::enable_if_t<ENTT_IS_EMPTY(Type)>()>: public sparse_set<Entity> {
     using underlying_type = sparse_set<Entity>;
 
 public:
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 87a9b00aa..4a8568343 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -56,7 +56,7 @@ function(SETUP_TARGET TARGET_NAME)
             $<$<AND:$<CONFIG:Release>,$<PLATFORM_ID:Windows>>:/O2>
     )
 
-    target_compile_definitions(${TARGET_NAME} PRIVATE ENTT_STANDALONE)
+    target_compile_definitions(${TARGET_NAME} PRIVATE ENTT_STANDALONE ${ARGN})
 endfunction()
 
 add_library(odr OBJECT odr.cpp)
@@ -65,27 +65,23 @@ SETUP_TARGET(odr)
 function(SETUP_BASIC_TEST TEST_NAME TEST_SOURCES)
     add_executable(${TEST_NAME} $<TARGET_OBJECTS:odr> ${TEST_SOURCES})
     target_link_libraries(${TEST_NAME} PRIVATE GTest::Main Threads::Threads)
-    SETUP_TARGET(${TEST_NAME})
+    SETUP_TARGET(${TEST_NAME} ${ARGN})
     add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME})
 endfunction()
 
 function(SETUP_LIB_TEST TEST_NAME)
     add_library(_${TEST_NAME} SHARED $<TARGET_OBJECTS:odr> lib/${TEST_NAME}/lib.cpp)
-    SETUP_TARGET(_${TEST_NAME})
-    SETUP_BASIC_TEST(lib_${TEST_NAME} lib/${TEST_NAME}/main.cpp)
-    target_compile_definitions(_${TEST_NAME} PRIVATE ENTT_API_EXPORT ${ARGV1})
-    target_compile_definitions(lib_${TEST_NAME} PRIVATE ENTT_API_IMPORT ${ARGV1})
+    SETUP_TARGET(_${TEST_NAME} ENTT_API_EXPORT)
+    SETUP_BASIC_TEST(lib_${TEST_NAME} lib/${TEST_NAME}/main.cpp ENTT_API_IMPORT)
     target_link_libraries(lib_${TEST_NAME} PRIVATE _${TEST_NAME})
 endfunction()
 
 function(SETUP_PLUGIN_TEST TEST_NAME)
     add_library(_${TEST_NAME} MODULE $<TARGET_OBJECTS:odr> lib/${TEST_NAME}/plugin.cpp)
-    SETUP_TARGET(_${TEST_NAME})
-    SETUP_BASIC_TEST(lib_${TEST_NAME} lib/${TEST_NAME}/main.cpp)
+    SETUP_TARGET(_${TEST_NAME} NOMINMAX ${ARGVN})
+    SETUP_BASIC_TEST(lib_${TEST_NAME} lib/${TEST_NAME}/main.cpp NOMINMAX PLUGIN="$<TARGET_FILE:_${TEST_NAME}>" ${ARGVN})
     target_include_directories(_${TEST_NAME} PRIVATE ${cr_INCLUDE_DIR})
     target_include_directories(lib_${TEST_NAME} PRIVATE ${cr_INCLUDE_DIR})
-    target_compile_definitions(lib_${TEST_NAME} PRIVATE NOMINMAX PLUGIN="$<TARGET_FILE:_${TEST_NAME}>" ${ARGV1})
-    target_compile_definitions(_${TEST_NAME} PRIVATE NOMINMAX ${ARGV1})
     target_link_libraries(lib_${TEST_NAME} PRIVATE ${CMAKE_DL_LIBS})
 endfunction()
 
@@ -172,6 +168,7 @@ SETUP_BASIC_TEST(handle entt/entity/handle.cpp)
 SETUP_BASIC_TEST(helper entt/entity/helper.cpp)
 SETUP_BASIC_TEST(observer entt/entity/observer.cpp)
 SETUP_BASIC_TEST(registry entt/entity/registry.cpp)
+SETUP_BASIC_TEST(registry_no_eto entt/entity/registry_no_eto.cpp ENTT_NO_ETO)
 SETUP_BASIC_TEST(runtime_view entt/entity/runtime_view.cpp)
 SETUP_BASIC_TEST(snapshot entt/entity/snapshot.cpp)
 SETUP_BASIC_TEST(sparse_set entt/entity/sparse_set.cpp)
diff --git a/test/entt/entity/registry_no_eto.cpp b/test/entt/entity/registry_no_eto.cpp
new file mode 100644
index 000000000..dadf5ca77
--- /dev/null
+++ b/test/entt/entity/registry_no_eto.cpp
@@ -0,0 +1,25 @@
+#include <gtest/gtest.h>
+#include <entt/entity/registry.hpp>
+
+struct empty_type {};
+
+bool operator==(const empty_type &lhs, const empty_type &rhs) {
+    return &lhs == &rhs;
+}
+
+TEST(Registry, NoEto) {
+    entt::registry registry;
+    const auto entity = registry.create();
+
+    registry.emplace<empty_type>(entity);
+    registry.emplace<int>(entity, 42);
+
+    ASSERT_NE(registry.raw<empty_type>(), nullptr);
+    ASSERT_NE(registry.try_get<empty_type>(entity), nullptr);
+    ASSERT_EQ(registry.view<empty_type>().get(entity), std::as_const(registry).view<const empty_type>().get(entity));
+
+    auto view = registry.view<empty_type, int>();
+    auto cview = std::as_const(registry).view<const empty_type, const int>();
+
+    ASSERT_EQ((std::get<0>(view.get<empty_type, int>(entity))), (std::get<0>(cview.get<const empty_type, const int>(entity))));
+}