Merge pull request #1380 from ednolan/enolan_submoduletestcmake1

Prevent CMake from attempting to configure test executables without Catch2

CMakeLists.txt

@@ -79,21 +79,32 @@ rapids_cmake_build_type(Release)
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules")
 
 # Don't build tests if configuring stdexec as a submodule of another
-# CMake project, unless they explicitly set STDEXEC_BUILD_TESTS=TRUE
-if (CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
+# CMake project, unless they explicitly set STDEXEC_BUILD_TESTS=TRUE,
+# or they enabled CTest's BUILD_TESTING option
+if ((CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME) OR BUILD_TESTING)
     set(STDEXEC_BUILD_TESTS_DEFAULT ON)
 else()
     set(STDEXEC_BUILD_TESTS_DEFAULT OFF)
 endif()
 option(STDEXEC_BUILD_TESTS "Build stdexec tests" ${STDEXEC_BUILD_TESTS_DEFAULT})
 
+# STDEXEC_BUILD_TESTS is used solely to configure CTest's BUILD_TESTING option,
+# which is CMake's preferred option for enabling testing when using CTest.
+set(BUILD_TESTING ${STDEXEC_BUILD_TESTS})
+
+if (BUILD_TESTING)
+  # CTest automatically calls enable_testing() if BUILD_TESTING is ON
+  # https://cmake.org/cmake/help/latest/module/CTest.html#module:CTest
+  include(CTest)
+endif()
+
 ##############################################################################
 # - Dependencies -------------------------------------------------------------
 
 # Initialize CPM
 rapids_cpm_init(OVERRIDE ${CMAKE_CURRENT_SOURCE_DIR}/cmake/versions.json)
 
-if (STDEXEC_BUILD_TESTS)
+if (BUILD_TESTING)
     # Add Catch2
     set(Catch2_VERSION 2.13.6)
     # Always download it, don't attempt to do `find_package(Catch2)` first
@@ -389,14 +400,6 @@ option(STDEXEC_ENABLE_IO_URING_TESTS "Enable io_uring tests" ${STDEXEC_FOUND_IO_
 option(STDEXEC_BUILD_DOCS "Build stdexec documentation" OFF)
 option(STDEXEC_BUILD_EXAMPLES "Build stdexec examples" ON)
 
-if (STDEXEC_BUILD_TESTS)
-  set(BUILD_TESTING ON)
-
-  # CTest automatically calls enable_testing() if BUILD_TESTING is ON
-  # https://cmake.org/cmake/help/latest/module/CTest.html#module:CTest
-  include(CTest)
-endif()
-
 # Configure documentation
 if(STDEXEC_BUILD_DOCS)
     add_subdirectory(docs)