如何避免使用GoogleTest混合测试代码和生产代码？

Question

I am starting to use GoogleTest. It seems that it needs a main file for running the tests:

Separate test cases across multiple files in google test

But currently in my demo application I already have a main file:

src/
-> MyType.h
-> main.cpp
-> Makefile

Which will eventually be my "production" application. I don't want to clutter that with gtest includes, macros etc.

Should I just create another main.cpp file in another folder eg: test/ that will contain all the specific gtest configuration so I would end up with:

src/
-> MyType.h
-> main.cpp
-> Makefile // Makefile for producing production code/binaries
Test/
-> MyTypeTest.h // Unittest for MyType
-> main.cpp // The "Test runner"
-> Makefile // Makefile for producing test executable

EDIT:

Found this based on cmake:

http://www.kaizou.org/2014/11/gtest-cmake/

which seems to be exactly what I am looking for.

Answer 1

The most sensible approach to this is to have a library for your production code and then two executables, one for production and another one for tests:

|-lib/
| |-Makefile
| |-mytype.h
| `-mytype.cpp
|-app/
| |-Makefile
| `-main.cpp
`-test/
  |-Makefile
  `-mytypetest.cpp

Notice that gtest distribution provides the gtest library and a gtest_main library with the standard main function for your test executable. So unless you need a custom main (rare case) you don't need to provide a main.cpp for your tests and can simply link against gtest_main , eg $(CC) mytypetest.cpp -o apptests -lapplib -lgtest_main -lgtest .

The library approach involves slightly more complex Makefile s, but it pays off in compilation time, since not having it implies you need to compile mytype.cpp once for production application and once for test executable.

Answer 2

There are probably a lot of ways to do this, but generally speaking, yes, you should add a test-specific main function to your project. This makes compilation a little bit more complex since you'll have to produce two separate binaries (one for your application and another for your tests) but this is a fairly typical setup.

Answer 3

I'd simply add a test.cpp file with a main and create a test target in my makefile so that I could either make - to build my production code - or make test - to build the tests. In actual projects I use cmake in very similar fashion (I sometimes bundle all common dependencies in a core.a library and then link both main and test against it).