diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6a0da47..71bc342 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -4,7 +4,7 @@ env:
   HOMEBREW_NO_INSTALL_CLEANUP: 1
   CTEST_NO_TESTS_ACTION: error
   CMAKE_BUILD_PARALLEL_LEVEL: 4
-  CTEST_PARALLEL_LEVEL: 4
+  CTEST_PARALLEL_LEVEL: 0
 
 on:
   push:
@@ -28,13 +28,14 @@ jobs:
 
     env:
       FC: gfortran-13
+      CMAKE_INSTALL_PREFIX: ~/libs
 
     steps:
 
     - uses: actions/checkout@v4
 
     - name: Configure
-      run: cmake --preset default -DBUILD_SHARED_LIBS:BOOL=${{ matrix.shared }} --install-prefix=${{ runner.temp }}
+      run: cmake --preset default -DBUILD_SHARED_LIBS:BOOL=${{ matrix.shared }}
 
     - name: Build
       run: cmake --build --preset default
diff --git a/cmake/options.cmake b/cmake/options.cmake
index ffc7f26..efd9bda 100644
--- a/cmake/options.cmake
+++ b/cmake/options.cmake
@@ -2,7 +2,14 @@ include(GNUInstallDirs)
 
 message(STATUS "${PROJECT_NAME} ${PROJECT_VERSION}  CMake ${CMAKE_VERSION} Toolchain ${CMAKE_TOOLCHAIN_FILE}")
 
-option(${PROJECT_NAME}_BUILD_TESTING "Build tests" ${PROJECT_IS_TOP_LEVEL})
+if(CMAKE_VERSION VERSION_LESS 3.21)
+  get_property(not_top DIRECTORY PROPERTY PARENT_DIRECTORY)
+  if(NOT not_top)
+    set(${PROJECT_NAME}_IS_TOP_LEVEL true)
+  endif()
+endif()
+
+option(${PROJECT_NAME}_BUILD_TESTING "Build tests" ${${PROJECT_NAME}_IS_TOP_LEVEL})
 
 # Necessary for shared library with Visual Studio / Windows oneAPI
 set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS true)