space-time-stack: allow API access to the stack + adding google test

CMakeLists.txt

@@ -272,6 +272,7 @@ endif()
 # Tests
 if(KokkosTools_ENABLE_TESTS)
   enable_testing()
+  include(cmake/BuildGTest.cmake)
   add_subdirectory(tests)
 endif()
 

cmake/BuildGTest.cmake

@@ -0,0 +1,35 @@
+# Look for Google Test and enable it as a target.
+#
+# The main targets that will be available are:
+#       * GTest::gtest
+#       * GTest::gmock
+#
+# References:
+#   * https://github.com/google/googletest
+#   * https://matgomes.com/integrate-google-test-into-cmake/
+#   * https://google.github.io/googletest/quickstart-cmake.html
+#   * https://jeremimucha.com/2021/04/cmake-fetchcontent/
+
+include(FetchContent)
+
+# Declare the Google Test dependency
+FetchContent_Declare(
+    googletest
+    GIT_REPOSITORY https://github.com/google/googletest.git
+    GIT_TAG        v1.14.0
+)
+
+# If not yet populated, add Google Test to the build with the following options:
+#       * disable installation of Google Test
+#       * enable GMock
+# Note that we could have used FetchContent_MakeAvailable instead, but it would then
+# use the default configuration that would install Google Test.
+FetchContent_GetProperties(googletest)
+if (NOT googletest_POPULATED)
+    FetchContent_Populate(googletest)
+
+    set(BUILD_GMOCK   ON)
+    set(INSTALL_GTEST OFF)
+
+    add_subdirectory(${googletest_SOURCE_DIR} ${googletest_BINARY_DIR} EXCLUDE_FROM_ALL)
+endif()