gtest_setup.txt

# Setting up Google Test

Many of the newer OpenDDS unit tests rely on Google Test, which can be set up
using Git submodules or by specifying an external location (system-wide or user-
defined).

Note: Any test executables which depend upon Gtest can use the googletest.mpb
MPC base project (in $DDS_ROOT/MPC/config) to pull in the required libraries.

## Using a Git Submodule

  1. Your OpenDDS git repo needs to have submodules enabled and
     the directory $DDS_ROOT/tests/googletest should not be empty.
     If it is empty, run "git submodule init" followed by "git submodule update"

     see https://git-scm.com/book/en/v2/Git-Tools-Submodules

  2. Build the Gtest library.
     Create the following directories:
       a. $DDS_ROOT/tests/googletest/build
       b. $DDS_ROOT/tests/googletest/build/install

     Change into the build directory just created and run cmake using
     $DDS_ROOT/tests/googletest as the source directory, and using
     $DDS_ROOT/tests/googletest/build/install as an install prefix:

     ~~~
     cd tests/googletest/build
     cmake -DCMAKE_INSTALL_PREFIX=./install ..
     ~~~

     Note: if using Visual C++ and your OpenDDS build is not static,
     enable gtest_force_shared_crt or BUILD_SHARED_LIBS. In addition,
     a couple other flags are probably necessary to select the proper
     build environment and disable TR1-Deprecation warnings:

     ~~~
     cd tests\googletest\build
     cmake -DCMAKE_INSTALL_PREFIX=.\install ^
           -Dgtest_force_shared_crt=ON ^
           -DCMAKE_CXX_FLAGS=/D_SILENCE_TR1_NAMESPACE_DEPRECATION_WARNING=1 ^
           -G "Visual Studio 15 2017 Win64" ..
     ~~~

     Then build and install the Gtest library using cmake from the build
     directory:

     ~~~
     cmake --build . --target install
     ~~~

  3. Configure and build OpenDDS as usual.


## Using an External Location

  1. Clone the Google Test repo into some directory (doesn't really matter where
     as the install target will be the _actual_ library directory).

     ~~~
     git clone https://github.com/google/googletest.git
     ~~~

  2. Follow the steps in "Using a Git Submodule" with the following differences:
      a. The install location can be anywhere you desire, or it can be completely
         omitted (in which case the default system location will be used).

      b. An elevated terminal/cmd shell will probably be required if the install
         prefix is omitted.

      c. When invoking the OpenDDS configure script, if the default system location
         is _not_ used, then the gtest switch can be used to inform the configure
         script where the gtest libraries are located. Otherwise, the configure script
         should detect the default location.

         ~~~
         ./configure --gtest=/path/the/gtest/install/dir
         ~~~

      d. Alternatively, the Gtest root can be overridden by setting the GTEST_ROOT
         environment variable before regenerating the build files with MWC.pl.

         For example (within the DDS_ROOT directory):

         Windows:
         ~~~
         set GTEST_ROOT=c:\path\to\gtest\root
         mwc.pl -type vs2017 DDS.mwc
         msbuild /m DDS_TAOv2_all.sln
         ~~~

         Unix:
         ~~~
         export GTEST_ROOT=/path/to/gtest/root
         mwc.pl -type gnuace DDS.mwc
         make
         ~~~