test: tests for monadic functions

Author: X1aomu

tests/test_expected/CMakeLists.txt

@@ -13,6 +13,7 @@ target_link_libraries(${PROJECT_NAME} Catch2::Catch2)
 target_sources(${PROJECT_NAME}
     PRIVATE
         base_tests.cpp
+        monadic_tests.cpp
         test_expected_main.cpp
 )
 
@@ -29,6 +30,7 @@ target_link_libraries(${PROJECT_NAME}_cpp20 Catch2::Catch2)
 target_sources(${PROJECT_NAME}_cpp20
     PRIVATE
         base_tests.cpp
+        monadic_tests.cpp
         test_expected_main.cpp
 )
 
@@ -45,5 +47,6 @@ target_link_libraries(${PROJECT_NAME}_cpp23 Catch2::Catch2)
 target_sources(${PROJECT_NAME}_cpp23
     PRIVATE
         base_tests.cpp
+        monadic_tests.cpp
         test_expected_main.cpp
 )

tests/test_expected/monadic_tests.cpp

@@ -0,0 +1,32 @@
+#include <string>
+
+#include <catch2/catch_all.hpp>
+
+#include <zeus/expected.hpp>
+
+using namespace zeus;
+
+TEST_CASE("and_then()", "[monadic]")
+{
+    using T        = std::string;
+    using Expected = expected<int, T>;
+
+    { // non-void
+        using Expected2 = expected<double, T>;
+
+        Expected e = 42;
+
+        auto const newVal = e.and_then([](int x) { return Expected2 {x * 2}; });
+
+        static_assert(std::is_same_v<std::remove_cv_t<decltype(newVal)>, Expected2>);
+    }
+    { // void
+        using Expected2 = expected<void, T>;
+
+        Expected e = 42;
+
+        auto const newVal = e.and_then([](int) -> Expected2 { return Expected2 {}; });
+
+        static_assert(std::is_same_v<std::remove_cv_t<decltype(newVal)>, Expected2>);
+    }
+}

tests/third_party/msvc/CMakeLists.txt

@@ -1 +1,2 @@
 add_subdirectory(msvc_stl_p0323r12_test)
+add_subdirectory(msvc_stl_p2505r5_test)

tests/third_party/msvc/msvc_stl_p2505r5_test/CMakeLists.txt

@@ -0,0 +1,10 @@
+project(msvc_stl_p2505r5_test)
+add_executable(${PROJECT_NAME})
+set_target_properties(${PROJECT_NAME} PROPERTIES CXX_STANDARD 20)
+
+target_link_libraries(${PROJECT_NAME} zeus::expected)
+
+target_sources(${PROJECT_NAME}
+    PRIVATE
+        msvc_stl_p2505r5_test.cpp
+)