c – Gtest：未定义的参考

我试图使用GoogleTest来测试一个简单的函数,但是当我在我的构建文件夹中运行make时,编译器会向我发出未定义的引用错误消息.我引用了gtest头文件,所以我不知道是什么问题.有任何想法吗？我是Unix和单元测试的整个主题的新手,所以我很可能会失去一些简单的东西.提前致谢！

错误消息：

CMakeFiles/Proj2.dir/main.cpp.o: In function `main':
main.cpp:(.text+0x1e): undefined reference to `testing::InitGoogleTest(int*,char**)'
main.cpp:(.text+0x23): undefined reference to `testing::UnitTest::GetInstance()'
main.cpp:(.text+0x2b): undefined reference to `testing::UnitTest::Run()'
collect2: error: ld returned 1 exit status

main.cpp中

#include "gtest/gtest.h"

int main(int argc,char **argv) {
    ::testing::InitGoogleTest(&argc,argv);
    return RUN_ALL_TESTS();
}

TEST.CPP

#include "gtest/gtest.h"
#include "Testable.h"

TEST(GetTwoTest,Two) {
    EXPECT_EQ(2,GetTwo());
}

Testable.cpp

#include "Testable.h"

int GetTwo() {
    return 3;
}

这是我的CMakeLists.txt文件：

cmake_minimum_required(VERSION 2.6)

SET(CMAKE_CXX_FLAGS "-std=gnu++11") #Turn on C++11 Support

set(FILES_TO_TEST Testable.cpp)
set(UNIT_TESTS Test.cpp)
set(MAIN_FILE main.cpp)

add_subdirectory(gtest) #Build all the gtest stuff
include_directories(gtest/include)
include_directories(.)
add_library(codetoTest ${FILES_TO_TEST})

add_executable(Proj2 ${MAIN_FILE})
target_link_libraries(Proj2 codetoTest)

add_executable(unit-test ${UNIT_TESTS})
target_link_libraries(unit-test gtest gtest_main rt pthread codetoTest)