Out with Eigen, in with FetchContent and gtest

README.md

@@ -113,7 +113,7 @@
 - [Using the superbuild pattern](chapter-08/recipe-01/README.md)
 - [Managing dependencies with a superbuild I. The Boost libraries](chapter-08/recipe-02/README.md)
 - [Managing dependencies with a superbuild II. The FFTW library](chapter-08/recipe-03/README.md)
-- [Managing dependencies with a superbuild III. The Eigen library](chapter-08/recipe-04/README.md)
+- [Managing dependencies with a superbuild III. The Google test framework](chapter-08/recipe-04/README.md)
 - [Managing your project as a superbuild](chapter-08/recipe-05/README.md)
 
 

chapter-08/README.md

@@ -3,5 +3,5 @@
 - [Using the superbuild pattern](recipe-01/README.md)
 - [Managing dependencies with a superbuild I. The Boost libraries](recipe-02/README.md)
 - [Managing dependencies with a superbuild II. The FFTW library](recipe-03/README.md)
-- [Managing dependencies with a superbuild III. The Eigen library](recipe-04/README.md)
+- [Managing dependencies with a superbuild III. The Google test framework](recipe-04/README.md)
 - [Managing your project as a superbuild](recipe-05/README.md)

chapter-08/recipe-04/README.md

@@ -1,4 +1,4 @@
-# Managing dependencies with a superbuild III. The Eigen library
+# Managing dependencies with a superbuild III. The Google test framework
 
 Abstract to be written ...
 

chapter-08/recipe-04/cxx-example-3.5/CMakeLists.txt

@@ -1,34 +1,53 @@
+# set minimum cmake version
 cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
 
-project(recipe-04 LANGUAGES CXX)
+# project name and language
+project(recipe-03 LANGUAGES CXX)
 
+# require C++11
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_EXTENSIONS OFF)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-set_property(DIRECTORY PROPERTY EP_BASE ${CMAKE_BINARY_DIR}/subprojects)
-
-option(Eigen3_FORCE_SUPERBUILD "Always build Eigen3 on our own" OFF)
-
-add_subdirectory(external/upstream)
-
-include(ExternalProject)
-ExternalProject_Add(${PROJECT_NAME}_core
-  DEPENDS
-    eigen3_external
-  SOURCE_DIR
-    ${CMAKE_CURRENT_SOURCE_DIR}/src
-  CMAKE_ARGS
-    -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
-    -DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}
-    -DCMAKE_CXX_EXTENSIONS=${CMAKE_CXX_EXTENSIONS}
-    -DCMAKE_CXX_STANDARD_REQUIRED=${CMAKE_CXX_STANDARD_REQUIRED}
-    -DEigen3_DIR=${Eigen3_DIR}
-  CMAKE_CACHE_ARGS
-    -DCMAKE_CXX_FLAGS:STRING=${CMAKE_CXX_FLAGS}
-    -DCMAKE_PREFIX_PATH:PATH=${CMAKE_PREFIX_PATH}
-  BUILD_ALWAYS
-    1
-  INSTALL_COMMAND
-    ""
-  )
+set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
+
+# example library
+add_library(sum_integers sum_integers.cpp)
+
+# main code
+add_executable(sum_up main.cpp)
+target_link_libraries(sum_up sum_integers)
+
+# we will use the network to fetch Google Test sources
+# make it possible to disable unit tests when not on network
+option(ENABLE_UNIT_TESTS "Enable unit tests" ON)
+message(STATUS "Enable testing: ${ENABLE_UNIT_TESTS}")
+
+include(googletest.cmake)
+
+if(ENABLE_UNIT_TESTS)
+  fetch_googletest(
+    ${CMAKE_CURRENT_SOURCE_DIR}
+    ${CMAKE_CURRENT_BINARY_DIR}/googletest
+    )
+
+  add_executable(cpp_test "")
+
+  target_sources(cpp_test
+    PRIVATE
+      test.cpp
+    )
+
+  target_link_libraries(cpp_test
+    PRIVATE
+      sum_integers
+      gtest_main
+    )
+
+  enable_testing()
+
+  add_test(
+    NAME google_test
+    COMMAND $<TARGET_FILE:cpp_test>
+    )
+endif()

chapter-08/recipe-04/cxx-example-3.5/googletest-download.cmake

@@ -0,0 +1,20 @@
+# code copied from https://crascit.com/2015/07/25/cmake-gtest/
+cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
+
+project(googletest-download LANGUAGES NONE)
+
+include(ExternalProject)
+
+ExternalProject_Add(
+  googletest
+  SOURCE_DIR "@GOOGLETEST_DOWNLOAD_ROOT@/googletest-src"
+  BINARY_DIR "@GOOGLETEST_DOWNLOAD_ROOT@/googletest-build"
+  GIT_REPOSITORY
+    https://github.com/google/googletest.git
+  GIT_TAG
+    release-1.8.0
+  CONFIGURE_COMMAND ""
+  BUILD_COMMAND ""
+  INSTALL_COMMAND ""
+  TEST_COMMAND ""
+  )

chapter-08/recipe-04/cxx-example-3.5/googletest.cmake

@@ -0,0 +1,50 @@
+# download and unpack googletest at configure time
+
+# the following code to fetch googletest
+# is inspired by and adapted after https://crascit.com/2015/07/25/cmake-gtest/
+
+function(fetch_googletest _download_module_path _download_root)
+  # Variable used in googletest-download.cmake
+  set(GOOGLETEST_DOWNLOAD_ROOT ${_download_root})
+  configure_file(
+    ${_download_module_path}/googletest-download.cmake
+    ${_download_root}/CMakeLists.txt
+    @ONLY
+    )
+  unset(GOOGLETEST_DOWNLOAD_ROOT)
+
+  execute_process(
+    COMMAND
+      "${CMAKE_COMMAND}" -G "${CMAKE_GENERATOR}" .
+    WORKING_DIRECTORY
+      ${_download_root}
+    )
+  execute_process(
+    COMMAND
+      "${CMAKE_COMMAND}" --build .
+    WORKING_DIRECTORY
+      ${_download_root}
+    )
+
+  # Prevent GoogleTest from overriding our compiler/linker options
+  # when building with Visual Studio
+  set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+  # Prevent GoogleTest from using PThreads
+  set(gtest_disable_pthreads ON CACHE BOOL "" FORCE)
+
+  # adds the targets: gtest, gtest_main, gmock, gmock_main
+  add_subdirectory(
+    ${_download_root}/googletest-src
+    ${_download_root}/googletest-build
+    )
+
+  # Silence std::tr1 warning on MSVC
+  if(MSVC)
+    foreach(_tgt gtest gtest_main gmock gmock_main)
+      target_compile_definitions(${_tgt}
+        PRIVATE
+          "_SILENCE_TR1_NAMESPACE_DEPRECATION_WARNING"
+        )
+    endforeach()
+  endif()
+endfunction()

chapter-08/recipe-04/cxx-example-3.5/main.cpp

@@ -0,0 +1 @@
+../../../chapter-04/recipe-01/cxx-example/main.cpp

chapter-08/recipe-04/cxx-example-3.5/menu.yml

@@ -1,25 +1,2 @@
-appveyor-vs:
-  definitions:
-    - Eigen3_FORCE_SUPERBUILD: 'ON'
-
-appveyor-msys:
-  definitions:
-    - Eigen3_FORCE_SUPERBUILD: 'ON'
-
-travis-linux:
-  definitions:
-    - Eigen3_FORCE_SUPERBUILD: 'ON'
-
-# OpenMP does not work with clang
-travis-osx:
-  definitions:
-    - Eigen3_FORCE_SUPERBUILD: 'ON'
-  failing_generators:
-    - 'Unix Makefiles'
-    - 'Ninja'
-
-local:
-  definitions:
-    - Eigen3_FORCE_SUPERBUILD: 'ON'
-  env:
-    - VERBOSE_OUTPUT: 'ON'
+targets:
+  - test

chapter-08/recipe-04/cxx-example-3.5/sum_integers.cpp

@@ -0,0 +1 @@
+../../../chapter-04/recipe-01/cxx-example/sum_integers.cpp

chapter-08/recipe-04/cxx-example-3.5/sum_integers.hpp

@@ -0,0 +1 @@
+../../../chapter-04/recipe-01/cxx-example/sum_integers.hpp

chapter-08/recipe-04/cxx-example-3.5/test.cpp

@@ -0,0 +1 @@
+../cxx-example/test.cpp