catch2 单包含导致测试中“未定义的引用”

Question

我见过很多有同样问题的例子，但它们并不适用于我的情况。

我有以下文件结构：

unit-tests/CMakeLists.txt
unit-tests/FlaAlgoTests/CMakeLists.txt
unit-tests/FlaAlgoTests/catch_test_runner.cpp

在Proj/CMakeLists.txt：

ExternalProject_Add(
        catch
        PREFIX ${CMAKE_BINARY_DIR}/catch2
        GIT_REPOSITORY https://github.com/catchorg/Catch2.git
        TIMEOUT 10
        UPDATE_COMMAND ${GIT_EXECUTABLE} pull
        CONFIGURE_COMMAND ""
        BUILD_COMMAND ""
        INSTALL_COMMAND ""
        LOG_DOWNLOAD ON
)
ExternalProject_Get_Property(catch source_dir)
include_directories(${source_dir}/single_include/catch2)

并在Proj/TestDir1/CMakeLists.txt：

add_executable(
        catch_test_runner
        catch_test_runner.cpp
)

哪里catch_test_runner.cpp：

#include <iostream>
#include "catch.hpp"

#define CATCH_CONFIG_MAIN

TEST_CASE("Yeet", "[beep]"){
    REQUIRE(true);
    REQUIRE(2 == 1);
}

所有这些看起来都很好，似乎基本上是我为此找到的众多指南的复制/粘贴。但是，我遇到以下问题：

[100%] Linking CXX executable catch_test_runner.exe
CMakeFiles/catch_test_runner.dir/catch_test_runner.o: In function `::____C_A_T_C_H____T_E_S_T__(void)':
/cygdrive/c/Users/dbak/Projects/firmware/unit-tests/FlaAlgoTests/catch_test_runner.cpp:7: undefined reference to `Catch::StringRef::StringRef(char const*)'
/cygdrive/c/Users/dbak/Projects/firmware/unit-tests/FlaAlgoTests/catch_test_runner.cpp:7:(.text+0x32): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `Catch::StringRef::StringRef(char const*)'
/cygdrive/c/Users/dbak/Projects/firmware/unit-tests/FlaAlgoTests/catch_test_runner.cpp:7: undefined reference to `Catch::AssertionHandler::AssertionHandler(Catch::StringRef const&, Catch::SourceLineInfo const&, Catch::StringRef, Catch::ResultDisposition::Flags)'

所以，显然它能够链接到catch.hpp，否则它将无法找到任何这些东西。显然我正在使用 catch 的 single_include 版本，这是我发现的同一问题的所有示例都存在的问题。

我做错了什么？

Answer 1

该行#define CATCH_CONFIG_MAIN告诉catch.hppheader 它也应该发出 Catch 实现。但为了这个目的，这一行应该出现在include之前catch.hpp：

#define CATCH_CONFIG_MAIN // This should come **before** including the 'catch.hpp'.
#include "catch.hpp"