Improve gtest finding, support local checkout.

Also fix library dependency order for monolith test.

1 files changed, 49 insertions, 0 deletions

diff --git a/cmake/CompileGTest.cmake b/cmake/CompileGTest.cmake
new file mode 100644
index 00000000..520ca06a
--- /dev/null
+++ b/cmake/CompileGTest.cmake
@@ -0,0 +1,49 @@
+# Find and compile the GTest library.
+
+message(STATUS "Checking for gtest")
+
+# Look for the sources.
+find_file(GTEST_ALL_CC gtest-all.cc PATHS
+  ${CMAKE_SOURCE_DIR}/third_party/googletest/googletest/src
+  /usr/src/gtest/src
+  NO_DEFAULT_PATH
+)
+
+if(GTEST_ALL_CC)
+  # ../.. from the source file is the source root.
+  get_filename_component(GTEST_SRC_DIR ${GTEST_ALL_CC} DIRECTORY)
+  get_filename_component(GTEST_SRC_ROOT ${GTEST_SRC_DIR} DIRECTORY)
+
+  # Look for the header file.
+  include(CheckIncludeFileCXX)
+  include_directories(SYSTEM ${GTEST_SRC_ROOT}/include)
+  check_include_file_cxx("gtest/gtest.h" HAVE_GTEST_GTEST_H)
+
+  if(HAVE_GTEST_GTEST_H)
+    message(STATUS "Found gtest: ${GTEST_SRC_ROOT}")
+
+    add_library(gtest
+      ${GTEST_SRC_DIR}/gtest-all.cc
+      ${GTEST_SRC_DIR}/gtest_main.cc)
+    target_include_directories(gtest PRIVATE ${GTEST_SRC_ROOT})
+
+    # Ignore all warnings for gtest. We don't care about their implementation.
+    check_cxx_compiler_flag("-w" HAVE_CXX_W QUIET)
+    if(HAVE_CXX_W)
+      set_target_properties(gtest PROPERTIES COMPILE_FLAGS "-w")
+    endif()
+
+    set(HAVE_GTEST TRUE)
+    set(TEST_CXX_FLAGS "")
+
+    check_cxx_compiler_flag("-Wno-global-constructors" HAVE_CXX_W_NO_GLOBAL_CONSTRUCTORS QUIET)
+    if(HAVE_CXX_W_NO_GLOBAL_CONSTRUCTORS)
+      set(TEST_CXX_FLAGS "${TEST_CXX_FLAGS} -Wno-global-constructors")
+    endif()
+
+    check_cxx_compiler_flag("-Wno-zero-as-null-pointer-constant" HAVE_CXX_W_NO_ZERO_AS_NULL_POINTER_CONSTANT QUIET)
+    if(HAVE_CXX_W_NO_ZERO_AS_NULL_POINTER_CONSTANT)
+      set(TEST_CXX_FLAGS "${TEST_CXX_FLAGS} -Wno-zero-as-null-pointer-constant")
+    endif()
+  endif()
+endif()