Getting started with Google Test (GTest) on Ubuntu

Google test is a framework for writing C++ unit tests. In this short post, I explain how to set it up in Ubuntu.

Start by installing the gtest development package:

sudo apt-get install libgtest-dev

Note that this package only install source files. You have to compile the code yourself to create the necessary library files. These source files should be located at /usr/src/gtest. Browse to this folder and use cmake to compile the library:

sudo apt-get install cmake # install cmake
cd /usr/src/gtest
sudo cmake CMakeLists.txt
sudo make
 
# copy or symlink libgtest.a and libgtest_main.a to your /usr/lib folder
sudo cp *.a /usr/lib

Lets say we now want to test the following simple squareRoot function:

// whattotest.cpp
#include <math.h>
 
double squareRoot(const double a) {
    double b = sqrt(a);
    if(b != b) { // nan check
        return -1.0;
    }else{
        return sqrt(a);
    }
}

In the following code, we create two tests that test the function using a simple assertion. There exists many other assertion macros in the framework (see http://code.google.com/p/googletest/wiki/Primer#Assertions). The code contains a small main function that will run all of the tests automatically. Nice and simple!

// tests.cpp
#include "whattotest.cpp"
#include <gtest/gtest.h>
 
TEST(SquareRootTest, PositiveNos) { 
    ASSERT_EQ(6, squareRoot(36.0));
    ASSERT_EQ(18.0, squareRoot(324.0));
    ASSERT_EQ(25.4, squareRoot(645.16));
    ASSERT_EQ(0, squareRoot(0.0));
}
 
TEST(SquareRootTest, NegativeNos) {
    ASSERT_EQ(-1.0, squareRoot(-15.0));
    ASSERT_EQ(-1.0, squareRoot(-0.2));
}
 
int main(int argc, char **argv) {
    testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}

The next step is to compile the code. I’ve set up a small CMakeLists.txt file below to compile the tests. This file locates the google test library and links it with the test application. Note that we also have to link to the pthread library or the application won’t compile.

cmake_minimum_required(VERSION 2.6)
 
# Locate GTest
find_package(GTest REQUIRED)
include_directories(${GTEST_INCLUDE_DIRS})
 
# Link runTests with what we want to test and the GTest and pthread library
add_executable(runTests tests.cpp)
target_link_libraries(runTests ${GTEST_LIBRARIES} pthread)

Compile and run the tests:

cmake CMakeLists.txt
make
./runTests

Have fun testing! You can download all of the code above at my Github page: https://github.com/smistad/GTest

References

http://code.google.com/p/googletest/wiki/Documentation
http://www.ibm.com/developerworks/aix/library/au-googletestingframework.html

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24 Responses

  1. Anonymous says:

    Really clear, simple, short guide that did exactly what I wanted. Thank you!

  2. Martin says:

    Hi,
    thanks for this guide. It is working now.

  3. Miguel B says:

    Thank you very much, this was very helpful!

  4. Quan Wang says:

    At the last step, when I type cmake CMakeLists.txt, I get these errors:

    CMake Error at /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:91 (MESSAGE):
    Could NOT find GTest (missing: GTEST_INCLUDE_DIR)
    Call Stack (most recent call first):
    /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:252 (_FPHSA_FAILURE_MESSAGE)
    /usr/share/cmake-2.8/Modules/FindGTest.cmake:150 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
    CMakeLists.txt:4 (find_package)

    — Configuring incomplete, errors occurred!

    Do you know how to solve this problem? Thanks.

  5. Deepakgiri says:

    my folder structure is as below :

    deepak@deepak:/usr/src/gtest$ ll
    total 1256
    drwxr-xr-x 6 root root 4096 Sep 18 18:29 ./
    drwxr-xr-x 7 root root 4096 Sep 18 18:03 ../
    drwxr-xr-x 2 root root 4096 Sep 18 18:03 cmake/
    -rw-r–r– 1 root root 11730 Sep 18 18:12 CMakeCache.txt
    drwxr-xr-x 7 root root 4096 Sep 18 18:12 CMakeFiles/
    -rw-r–r– 1 root root 1552 Sep 18 18:12 cmake_install.cmake
    -rw-r–r– 1 root root 8664 Apr 16 2011 CMakeLists.txt
    -rw-r–r– 1 root root 1218562 Sep 18 18:12 libgtest.a
    -rw-r–r– 1 root root 3726 Sep 18 18:12 libgtest_main.a
    -rw-r–r– 1 root root 5903 Sep 18 18:12 Makefile
    drwxr-xr-x 2 root root 4096 Sep 18 18:03 src/
    drwxr-xr-x 3 root root 4096 Sep 19 14:48 unittest/
    deepak@deepak:/usr/src/gtest$ cd unittest/
    deepak@deepak:/usr/src/gtest/unittest$ ll
    total 52
    drwxr-xr-x 3 root root 4096 Sep 19 14:48 ./
    drwxr-xr-x 6 root root 4096 Sep 18 18:29 ../
    -rw-r–r– 1 root root 12273 Sep 19 12:11 CMakeCache.txt
    drwxr-xr-x 9 root root 4096 Sep 19 14:48 CMakeFiles/
    -rw-r–r– 1 root root 1579 Sep 18 18:40 cmake_install.cmake
    -rw-r–r– 1 root root 296 Sep 19 14:48 CMakeLists.txt
    -rw-r–r– 1 root root 332 Sep 19 13:00 CMakeLists.txt~
    -rw-r–r– 1 root root 4574 Sep 19 14:48 Makefile
    -rw-r–r– 1 root root 499 Sep 19 14:22 tests.cpp
    -rw-r–r– 1 root root 175 Sep 18 18:33 whattotest.cpp

  6. Deepakgiri says:

    Hi All,

    I got some reference error while execute “make” command.
    Error :
    Linking CXX executable runTests
    CMakeFiles/runTests.dir/tests.cpp.o: In function `testing::AssertionResult testing::internal::CmpHelperEQ(char const*, char const*, int const&, double const&)':
    tests.cpp:(.text._ZN7testing8internal11CmpHelperEQIidEENS_15AssertionResultEPKcS4_RKT_RKT0_[testing::AssertionResult testing::internal::CmpHelperEQ(char const*, char const*, int const&, double const&)]+0x9b): undefined reference to `testing::internal::EqFailure(char const*, char const*, testing::internal::String const&, testing::internal::String const&, bool)’
    CMakeFiles/runTests.dir/tests.cpp.o: In function `testing::AssertionResult testing::internal::CmpHelperEQ(char const*, char const*, double const&, double const&)':
    tests.cpp:(.text._ZN7testing8internal11CmpHelperEQIddEENS_15AssertionResultEPKcS4_RKT_RKT0_[testing::AssertionResult testing::internal::CmpHelperEQ(char const*, char const*, double const&, double const&)]+0x99): undefined reference to `testing::internal::EqFailure(char const*, char const*, testing::internal::String const&, testing::internal::String const&, bool)’
    collect2: ld returned 1 exit status
    make[2]: *** [runTests] Error 1
    make[1]: *** [CMakeFiles/runTests.dir/all] Error 2
    make: *** [all] Error 2

    Please help me in this.

    Thanks,
    Deepakgiri Aparnathi

  7. olupot says:

    Hey buddy, lovely Blog. Thanx for the good work. I love test driven design but was finding it rather hard to implement in C++ because of the libararies. Thanx alot.

  8. David says:

    You’ve written that to run it:

    cmake CMakeLists.txt
    make
    ./runTests

    It works, but then a lot of files has been created. Is it possible to run it in another way, e.g. I have got some ode to test I am writing some testSuite for this and then to run it I type, e.g:

    g++ -googleTest testSuite.cpp -o testSuite

    Thanks

    • Erik Smistad says:

      cmake creates a lot of files. If you don’t like to have all of those files in your source folder you can always create a separate (build) folder for this.

      For instance:

      mkdir build
      cd build
      cmake ../
      make

  9. Ramesh says:

    Thanks!

  10. Chetan says:

    If you get lots of errors after executing

    sudo cmake CMakeLists.txt

    update your libraries, by executing :

    sudo apt-get build-essentials

  11. Thanks. Very nice and simple tut.

  12. Anonymous says:

    I’m so thank, it helps me alot

  13. Venkat says:

    Thanks, It hedlped me how to get started….

  14. Janne Pohjoinen says:

    That was helpful, thanks!

  15. jules says:

    Hey mate,

    thanks alot! As already mentioned short but to the point and very informative…

  16. piponazo says:

    Very helpful! I used to install the libgtest-dev package and then to compile the libraries from the tarball downloaded from the google-test webpage. I didn’t know that the ubuntu package install those src files.

    I would like to suggest to compile the libraries as shared ones using the following command for configuring the project:

    sudo cmake -D BUILD_SHARED_LIBS=ON ..

    I commonly prefer to use shared libraries in front of static ones.

    Regards!

  17. simon says:

    simple and helpful, thanks

  18. Thanks says:

    It helped me alot, Thanks.. :)

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