CMake: Allow usage of QtStandaloneTestTemplateProject as package component

Currently in order to compile a Qt6 test standalone one needs to use
the qt-cmake-standalone-test script which will load the
Qt6BuildInternals/QtStandaloneTestTemplateProject/CMakeLists.txt project
with the current test source directory to create a complete CMake project.

This commit will allow a test to have these lines at top:

cmake_minimum_required(VERSION 3.16)

if (NOT QT_BUILD_STANDALONE_TESTS AND NOT QT_BUILDING_QT)
    project(a_qt_test LANGUAGES C CXX ASM)
    find_package(Qt6BuildInternals COMPONENTS STANDALONE_TEST)
endif()

and be standalone and work with any IDE capable of loading CMake projects.

Fixes: QTCREATORBUG-25389
Change-Id: If3f878b7e560a8bfbb604a8f1aa30b7962742e66
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
(cherry picked from commit 0a1256a52d8c6c1b85a10f7dc94dfc34e3540040)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

4 files changed, 46 insertions, 30 deletions

diff --git a/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake b/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake
index f2d20a1bc2..5d8903f90a 100644
--- a/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake
+++ b/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake
@@ -636,3 +636,16 @@ macro(qt_examples_build_end)
 
     set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ${BACKUP_CMAKE_FIND_ROOT_PATH_MODE_PACKAGE})
 endmacro()
+
+if ("STANDALONE_TEST" IN_LIST Qt6BuildInternals_FIND_COMPONENTS)
+    include(${CMAKE_CURRENT_LIST_DIR}/QtStandaloneTestTemplateProject/Main.cmake)
+    if (NOT PROJECT_VERSION_MAJOR)
+        get_property(_qt_major_version TARGET ${QT_CMAKE_EXPORT_NAMESPACE}::Core PROPERTY INTERFACE_QT_MAJOR_VERSION)
+        set(PROJECT_VERSION ${Qt${_qt_major_version}Core_VERSION})
+
+        string(REPLACE "." ";" _qt_core_version_list ${PROJECT_VERSION})
+        list(GET _qt_core_version_list 0 PROJECT_VERSION_MAJOR)
+        list(GET _qt_core_version_list 1 PROJECT_VERSION_MINOR)
+        list(GET _qt_core_version_list 2 PROJECT_VERSION_PATCH)
+    endif()
+endif()
diff --git a/cmake/QtBuildInternals/QtStandaloneTestTemplateProject/CMakeLists.txt b/cmake/QtBuildInternals/QtStandaloneTestTemplateProject/CMakeLists.txt
index a84c567b5a..564ed610c8 100644
--- a/cmake/QtBuildInternals/QtStandaloneTestTemplateProject/CMakeLists.txt
+++ b/cmake/QtBuildInternals/QtStandaloneTestTemplateProject/CMakeLists.txt
@@ -3,19 +3,7 @@ project(qt_single_test VERSION 6.0.0 LANGUAGES C CXX ASM)
 
 find_package(Qt6 REQUIRED COMPONENTS BuildInternals)
 
-# Includes QtSetup and friends for private CMake API.
-qt_build_internals_set_up_private_api()
-
-# Find all StandaloneTestsConfig.cmake files, and include them
-# This will find all Qt packages that are required for standalone tests.
-# It will find more packages that needed for a certain test, but will ensure any test can
-# be built.
-qt_get_standalone_tests_confg_files_path(standalone_tests_config_path)
-
-file(GLOB config_files "${standalone_tests_config_path}/*")
-foreach(file ${config_files})
-    include("${file}")
-endforeach()
+include(${CMAKE_CURRENT_LIST_DIR}/Main.cmake)
 
 # Get the absolute path of the passed-in project dir, relative to the current working directory
 # of the calling script, rather than relative to this source directory.
@@ -27,10 +15,5 @@ else()
     set(absolute_project_path "${QT_STANDALONE_TEST_PATH}")
 endif()
 
-# Just before adding the test, change the local (non-cache) install prefix to something other than
-# the Qt install prefix, so that tests don't try to install and pollute the Qt install prefix.
-# Needs to be called after qt_get_standalone_tests_confg_files_path().
-qt_set_up_fake_standalone_tests_install_prefix()
-
 # Add the test project path as a subdirectory project.
 add_subdirectory("${absolute_project_path}" "build_dir")
diff --git a/cmake/QtBuildInternals/QtStandaloneTestTemplateProject/Main.cmake b/cmake/QtBuildInternals/QtStandaloneTestTemplateProject/Main.cmake
new file mode 100644
index 0000000000..38e1d75d87
--- /dev/null
+++ b/cmake/QtBuildInternals/QtStandaloneTestTemplateProject/Main.cmake
@@ -0,0 +1,18 @@
+# Includes QtSetup and friends for private CMake API.
+qt_build_internals_set_up_private_api()
+
+# Find all StandaloneTestsConfig.cmake files, and include them
+# This will find all Qt packages that are required for standalone tests.
+# It will find more packages that needed for a certain test, but will ensure any test can
+# be built.
+qt_get_standalone_tests_confg_files_path(standalone_tests_config_path)
+
+file(GLOB config_files "${standalone_tests_config_path}/*")
+foreach(file ${config_files})
+    include("${file}")
+endforeach()
+
+# Just before adding the test, change the local (non-cache) install prefix to something other than
+# the Qt install prefix, so that tests don't try to install and pollute the Qt install prefix.
+# Needs to be called after qt_get_standalone_tests_confg_files_path().
+qt_set_up_fake_standalone_tests_install_prefix()
diff --git a/cmake/QtTestHelpers.cmake b/cmake/QtTestHelpers.cmake
index 4957e6ae49..249f771583 100644
--- a/cmake/QtTestHelpers.cmake
+++ b/cmake/QtTestHelpers.cmake
@@ -385,18 +385,20 @@ function(qt_internal_add_test name)
             "${CMAKE_CURRENT_SOURCE_DIR}")
         qt_path_join(testdata_install_dir ${QT_INSTALL_DIR}
                      "${relative_path_to_test_project}")
-        foreach(testdata IN LISTS arg_TESTDATA)
-            set(testdata "${CMAKE_CURRENT_SOURCE_DIR}/${testdata}")
-            if (IS_DIRECTORY "${testdata}")
-                qt_install(
-                    DIRECTORY "${testdata}"
-                    DESTINATION "${testdata_install_dir}")
-            else()
-                qt_install(
-                    FILES "${testdata}"
-                    DESTINATION "${testdata_install_dir}")
-            endif()
-        endforeach()
+        if (testdata_install_dir)
+            foreach(testdata IN LISTS arg_TESTDATA)
+                set(testdata "${CMAKE_CURRENT_SOURCE_DIR}/${testdata}")
+                if (IS_DIRECTORY "${testdata}")
+                    qt_install(
+                        DIRECTORY "${testdata}"
+                        DESTINATION "${testdata_install_dir}")
+                else()
+                    qt_install(
+                        FILES "${testdata}"
+                        DESTINATION "${testdata_install_dir}")
+                endif()
+            endforeach()
+        endif()
     endif()
 
 endfunction()