How to integrate g++ and gtest in one cmake file - c++

Question

I'm trying to integrate a normal compilation and a unit-test with gtest into one cmake file, but I don't know how to achieve this. Here is my project:
|---include
| |---Student.h
|
|---src
| |---Student.cpp
| |---main.cpp
|
|---unittest
| |---TestStudent.cpp
|
|---CMakeLists.txt # how to write this file?
So, Student.h, Student.cpp and main.cpp is the source code, TestStudent.cpp is the test code, which includes gtest/gtest.h and a main function, here it is:
#include "gtest/gtest.h"
#include "Student.h"
class TestStudent : public ::testing::Test
{
protected:
Student *ps;
void SetUp() override
{
ps = new Student(2, "toto");
}
void TearDown() override
{
delete ps;
}
};
TEST_F(TestStudent, ID)
{
EXPECT_TRUE(ps->GetID() == 2);
EXPECT_TRUE(ps->GetName() == "toto");
}
int main(int argc, char **argv)
{
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
Now, if I want to compile the source code, I need to run g++ -std=c++11 Student.cpp main.cpp -o a.out, whereas if I want to compile the test code, I need to run g++ -std=c++11 TestStudent.cpp Student.cpp -lgtest -lpthread -o test.out.
So, how could I write the CMakeLists.txt to allow me to compile the different targets, such as cmake NORMAL and cmake TEST?

Answer 1

As already pointed out in the comments use multiple targets via add_executable. The following CMakeLists.txt will produce two targets generating the executables student and student-test.
The last three lines can be omitted if you don't care about CTest.
cmake_minimum_required(VERSION 3.9)
project(Student CXX)
set(CMAKE_CXX_STANDARD 11)
set(SOURCES src/Student.cpp)
set(INCLUDES include)
find_package(GTest REQUIRED)
add_executable(student src/main.cpp ${SOURCES})
target_include_directories(student PRIVATE ${INCLUDES})
add_executable(student-test unittest/TestStudent.cpp ${SOURCES})
target_include_directories(student-test PRIVATE ${INCLUDES})
target_link_libraries(student-test GTest::GTest GTest::Main)
enable_testing()
include(GoogleTest)
gtest_add_tests(TARGET student-test AUTO)