T73268: Link C/C++ unit tests into single executable

This commit introduces a new way to build unit tests. It is now possible
for each module to generate its own test library. The tests in these
libraries are then bundled into a single executable.

The test executable can be run with `ctest`. Even though the tests
reside in a single executable, they are still exposed as individual
tests to `ctest`, and thus can be selected via its `-R` argument.

Not yet ported tests still build & run as before.

The following rules apply:

- Test code should reside in the same directory as the code under test.
- Tests that target functionality in `somefile.{c,cc}` should reside in
  `somefile_test.cc`.
- The namespace for tests is the `tests` sub-namespace of the code under
  test. For example, tests for `blender::bke` should be in
  `blender::bke:tests`.
- The test files should be listed in the module's `CMakeLists.txt` in a
  `blender_add_test_lib()` call. See the `blenkernel` module for an
  example.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D7649

2 files changed, 41 insertions, 0 deletions

diff --git a/build_files/cmake/Modules/GTestTesting.cmake b/build_files/cmake/Modules/GTestTesting.cmake
index c36b264a300..ea9a1edeb43 100644
--- a/build_files/cmake/Modules/GTestTesting.cmake
+++ b/build_files/cmake/Modules/GTestTesting.cmake
@@ -37,6 +37,11 @@ macro(BLENDER_SRC_GTEST_EX)
     if(WIN32)
       set(MANIFEST "${CMAKE_BINARY_DIR}/tests.exe.manifest")
     endif()
+
+    add_definitions(-DBLENDER_GFLAGS_NAMESPACE=${GFLAGS_NAMESPACE})
+    add_definitions(${GFLAGS_DEFINES})
+    add_definitions(${GLOG_DEFINES})
+
     add_executable(${TARGET_NAME} ${ARG_SRC} ${MANIFEST})
     target_include_directories(${TARGET_NAME} PUBLIC "${TEST_INC}")
     target_include_directories(${TARGET_NAME} SYSTEM PUBLIC "${TEST_INC_SYS}")
diff --git a/build_files/cmake/macros.cmake b/build_files/cmake/macros.cmake
index efe05d0bf5f..708efc3d2f7 100644
--- a/build_files/cmake/macros.cmake
+++ b/build_files/cmake/macros.cmake
@@ -354,6 +354,42 @@ function(blender_add_lib
   set_property(GLOBAL APPEND PROPERTY BLENDER_LINK_LIBS ${name})
 endfunction()
 
+# blender_add_test_lib() is used to define a test library. It is intended to be
+# called in tandem with blender_add_lib(). The test library will be linked into
+# the bf_gtest_runner_test executable (see tests/gtests/CMakeLists.txt).
+function(blender_add_test_lib
+  name
+  sources
+  includes
+  includes_sys
+  library_deps
+  )
+
+  add_cc_flags_custom_test(${name} PARENT_SCOPE)
+
+  # Otherwise external projects will produce warnings that we cannot fix.
+  remove_strict_flags()
+
+  # This duplicates logic that's also in GTestTesting.cmake, macro BLENDER_SRC_GTEST_EX.
+  # TODO(Sybren): deduplicate after the general approach in D7649 has been approved.
+  LIST(APPEND includes
+    ${CMAKE_SOURCE_DIR}/tests/gtests
+  )
+  LIST(APPEND includes_sys
+    ${GLOG_INCLUDE_DIRS}
+    ${GFLAGS_INCLUDE_DIRS}
+    ${CMAKE_SOURCE_DIR}/extern/gtest/include
+    ${CMAKE_SOURCE_DIR}/extern/gmock/include
+  )
+  add_definitions(-DBLENDER_GFLAGS_NAMESPACE=${GFLAGS_NAMESPACE})
+  add_definitions(${GFLAGS_DEFINES})
+  add_definitions(${GLOG_DEFINES})
+
+  blender_add_lib__impl(${name} "${sources}" "${includes}" "${includes_sys}" "${library_deps}")
+
+  set_property(GLOBAL APPEND PROPERTY BLENDER_TEST_LIBS ${name})
+endfunction()
+
 # Ninja only: assign 'heavy pool' to some targets that are especially RAM-consuming to build.
 function(setup_heavy_lib_pool)
   if(WITH_NINJA_POOL_JOBS AND NINJA_MAX_NUM_PARALLEL_COMPILE_HEAVY_JOBS)