3.9 KiB
Using GoogleTest from various build systems
GoogleTest comes with pkg-config files that can be used to determine all necessary flags for compiling and linking to GoogleTest (and GoogleMock). Pkg-config is a standardised plain-text format containing
- the includedir (-I) path
- necessary macro (-D) definitions
- further required flags (-pthread)
- the library (-L) path
- the library (-l) to link to
All current build systems support pkg-config in one way or another. For
all examples here we assume you want to compile the sample
samples/sample3_unittest.cc.
CMake
Using pkg-config in CMake is fairly easy:
cmake_minimum_required(VERSION 3.0)
cmake_policy(SET CMP0048 NEW)
project(my_gtest_pkgconfig VERSION 0.0.1 LANGUAGES CXX)
find_package(PkgConfig)
pkg_search_module(GTEST REQUIRED gtest_main)
add_executable(testapp samples/sample3_unittest.cc)
target_link_libraries(testapp ${GTEST_LDFLAGS})
target_compile_options(testapp PUBLIC ${GTEST_CFLAGS})
include(CTest)
add_test(first_and_only_test testapp)
It is generally recommended that you use target_compile_options + _CFLAGS
over target_include_directories + _INCLUDE_DIRS as the former includes not
just -I flags (GoogleTest might require a macro indicating to internal headers
that all libraries have been compiled with threading enabled. In addition,
GoogleTest might also require -pthread in the compiling step, and as such
splitting the pkg-config Cflags variable into include dirs and macros for
target_compile_definitions() might still miss this). The same recommendation
goes for using _LDFLAGS over the more commonplace _LIBRARIES, which
happens to discard -L flags and -pthread.
Autotools
Finding GoogleTest in Autoconf and using it from Automake is also fairly easy:
In your configure.ac:
AC_PREREQ([2.69])
AC_INIT([my_gtest_pkgconfig], [0.0.1])
AC_CONFIG_SRCDIR([samples/sample3_unittest.cc])
AC_PROG_CXX
PKG_CHECK_MODULES([GTEST], [gtest_main])
AM_INIT_AUTOMAKE([foreign subdir-objects])
AC_CONFIG_FILES([Makefile])
AC_OUTPUT
and in your Makefile.am:
check_PROGRAMS = testapp
TESTS = $(check_PROGRAMS)
testapp_SOURCES = samples/sample3_unittest.cc
testapp_CXXFLAGS = $(GTEST_CFLAGS)
testapp_LDADD = $(GTEST_LIBS)
Meson
Meson natively uses pkgconfig to query dependencies:
project('my_gtest_pkgconfig', 'cpp', version : '0.0.1')
gtest_dep = dependency('gtest_main')
testapp = executable(
'testapp',
files(['samples/sample3_unittest.cc']),
dependencies : gtest_dep,
install : false)
test('first_and_only_test', testapp)
Plain Makefiles
Since pkg-config is a small Unix command-line utility, it can be used
in handwritten Makefiles too:
GTEST_CFLAGS = `pkg-config --cflags gtest_main`
GTEST_LIBS = `pkg-config --libs gtest_main`
.PHONY: tests all
tests: all
./testapp
all: testapp
testapp: testapp.o
$(CXX) $(CXXFLAGS) $(LDFLAGS) $< -o $@ $(GTEST_LIBS)
testapp.o: samples/sample3_unittest.cc
$(CXX) $(CPPFLAGS) $(CXXFLAGS) $< -c -o $@ $(GTEST_CFLAGS)
Help! pkg-config can't find GoogleTest!
Let's say you have a CMakeLists.txt along the lines of the one in this
tutorial and you try to run cmake. It is very possible that you get a
failure along the lines of:
-- Checking for one of the modules 'gtest_main'
CMake Error at /usr/share/cmake/Modules/FindPkgConfig.cmake:640 (message):
None of the required 'gtest_main' found
These failures are common if you installed GoogleTest yourself and have not
sourced it from a distro or other package manager. If so, you need to tell
pkg-config where it can find the .pc files containing the information.
Say you installed GoogleTest to /usr/local, then it might be that the
.pc files are installed under /usr/local/lib64/pkgconfig. If you set
export PKG_CONFIG_PATH=/usr/local/lib64/pkgconfig
pkg-config will also try to look in PKG_CONFIG_PATH to find gtest_main.pc.