Bsrgvty

I am having hard time trying to install Google C++ Mocking Framework. I have successfully run sudo apt-get install google-mock. Then I tried to compile this sample file

#include "gmock/gmock.h"
int main(int argc, char** argv) 
 ::testing::InitGoogleMock(&argc, argv);
 return RUN_ALL_TESTS();

with g++ -lgmock main.cpp and these errors have shown

main.cpp:(.text+0x1e): undefined reference to `testing::InitGoogleMock(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

I guess the linker can not find the library files. Does anybody know how to fix this?

OK, I've now successfully started using gmock by building my own version as per the README provided with the source download from googlemock project website.

Get the download zip from the website:
http://code.google.com/p/googlemock/downloads/list

Unzip this to a directory, say $GMOCK_ROOT. Then, as per README instructions:

cd $GMOCK_ROOT
mkdir build
cd build
g++ -I../gtest/include -I../gtest -I../include -I.. -c ../gtest/src/gtest-all.cc
g++ -I../gtest/include -I../gtest -I../include -I.. -c ../src/gmock-all.cc
ar -rv libgmock.a gtest-all.o gmock-all.o

Thus you have your own libgmock.a in $GMOCK_ROOT/build. You actually also need pthreads to compile, so your compile command after that becomes:

g++ -I$GMOCK_ROOT/include/ main.cpp -L$GMOCK_ROOT/build -lgmock -lpthread

libgmock-dev will be included in the default Ubuntu 18.10 repositories, Otherwise in earlier Ubuntu releases you have to manually download and install it.

sudo apt-get install libgmock-dev
cd /usr/src/gmock
sudo mkdir build
sudo cmake ..
sudo make
sudo cp *.a /usr/lib

To give context to Pavel's answer, the compiled Google Mock binary is not distributed with the Ubuntu package because of the reason given here. This explanation is for Google Test, but the principle applies to any C++ library.

Specifically, it says:

In the early days, we said that you could install compiled Google Test
libraries on *nix systems using make install. Then every user of your
machine can write tests without recompiling Google Test.

This seemed like a good idea, but it has a got-cha: every user needs
to compile his tests using the same compiler flags used to compile the
installed Google Test libraries; otherwise he may run into undefined
behaviors (i.e. the tests can behave strangely and may even crash for
no obvious reasons).

Why? Because C++ has this thing called the One-Definition Rule: if two
C++ source files contain different definitions of the same
class/function/variable, and you link them together, you violate the
rule. The linker may or may not catch the error (in many cases it's
not required by the C++ standard to catch the violation). If it
doesn't, you get strange run-time behaviors that are unexpected and
hard to debug.

If you compile Google Test and your test code using different compiler
flags, they may see different definitions of the same
class/function/variable (e.g. due to the use of #if in Google Test).
Therefore, for your sanity, we recommend to avoid installing
pre-compiled Google Test libraries. Instead, each project should
compile Google Test itself such that it can be sure that the same
flags are used for both Google Test and the tests.

So your original problem was because installing the google-mock package only installed the source code, and when you tried to compile your sample application, no gmock library could be found.

In total, i use two installation methods, but in the second method you need to create the 'CMakeLists.txt' (where the data of your project will be indicated, subdirectory) file yourself and put it in the '/root/my_build directory'. I needed to uninstall the old version of 'cmake' and install a new one. I tried to install on Ubuntu 18.04.3 LTS 'gmock' on the root and everything related to its installation.

method 1:

# apt search gmock

# apt-get installyour version gmock

method 2:

# apt install unzip

# wget https://github.com/cfmobile/gmock/archive/master.zip

# unzip master.zip -d /$GMOCK_ROOT

# cd $GMOCK_ROOT

# mkdir my_build

# cd my_build

# cmake ..

# cd .. (exit from my_build, if 'CMakeLists.txt' not found, you must create it
yourself).

find and delete the old version cmake:

# apt list --installed | grep cmake

# apt-get remove cmake

# cmake --version

# reboot

install new version cmake:

# wget https://github.com/Kitware/CMake/releases/download/v3.15.3/cmake-3.15.3.tar.gz

# tar -zxvf cmake-3.15.3.tar.gz

# cd cmake-3.15.3

# ./configure

# make

# make install

# reboot

again go back to /root/my_build:

# cd my_build

# cmake ..

# make --jobs 4

# cd $GMOCK_HOME/gtest

# mkdir

# cd my_build

# cmake ..

# make --jobs 4