Provide automatic gtest download as backup option

Author: gpospelov

cmake/modules/CodeTools.cmake

@@ -46,6 +46,17 @@ function(project_testcoverage_setup)
         )
 endfunction()
 
+# Fetches google test version 1.12.1
+function(fetch_googletest)
+  include(FetchContent)
+  FetchContent_Declare(
+    googletest
+    GIT_REPOSITORY https://github.com/google/googletest.git
+    GIT_TAG 58d77fa8070e8cec2dc1ed015d66b454c8d78850)
+FetchContent_MakeAvailable(googletest)
+  message(VERBOSE "GTest binaries are present at ${googletest_BINARY_DIR}")
+endfunction()
+
 # Setups targets for code processing.
 
 function(project_codetools_setup)

tests/CMakeLists.txt

@@ -1,6 +1,14 @@
 enable_testing()
 
 find_package(GTest 1.10 QUIET CONFIG)
+if (NOT GTest_FOUND)
+  message(WARNING "GTest with version >= \"1.10\" was not found, fetching from internet" )
+  fetch_googletest()
+endif()
+find_package_message(
+  GTest_DETAILS
+  "Found GTest: ${GTest_DIR} (version \"${GTest_VERSION}\")"
+  "[${GTest_FOUND}][${GTest_DIR}][v${GTest_VERSION}]")
 
 include(GoogleTest)