Make standalone tests build via top level repo project

Previously repo/tests/CMakeLists.txt was a standalone project on which
CMake could be called. This was useful for Coin to be able to build
and package only tests, but was a bit troublesome because that means
having to specify the usual boilerplate like minimum CMake version,
which packages to find in every tests.pro project.

Instead of having a separate standalone project, modify the top level
project and associated CMake code to allow passing a special
QT_BUILD_STANDALONE_TESTS variable, which causes the top level project
to build only tests, and find Qt in the previously installed qt
location.

This also means that when building a repo, we generate a
${repo_name}TestsConfig.cmake file which does find_package on all the
modules that have been built as part of that repo. So that when
standalone tests bare built for that repo, the modules are
automatically found.

qt_set_up_standalone_tests_build() is modified to be a no-op because
it is not needed anymore. Its usage should be removed from all the
other repos, and then removed from qtbase.

Non-adjusted tests/CMakeLists.txt projects in other repositories
should still be buildable with the current code, until they are updated
to the new format.

Adjust the Coin build instructions to build the standalone tests in a
separate directory.

Adjust pro2cmake to generate new structure for the tests/tests.pro
projects.

Adjust the qtbase tests project.

Fixes: QTBUG-79239
Change-Id: Ib4b66bc772d8876cdcbae1e90ce5a5a5234fa675
Reviewed-by: Qt CMake Build Bot
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 9 insertions, 2 deletions

diff --git a/cmake/QtAutoDetect.cmake b/cmake/QtAutoDetect.cmake
index a1e66ffcbe..7864d40501 100644
--- a/cmake/QtAutoDetect.cmake
+++ b/cmake/QtAutoDetect.cmake
@@ -2,9 +2,12 @@
 # Collection of auto dection routines to improve the user eperience when
 # building Qt from source.
 #
+# Make sure to not run detection when building standalone tests, because the detection was already
+# done when initially configuring qtbase.
 
 function(qt_auto_detect_android)
-    if(DEFINED CMAKE_TOOLCHAIN_FILE AND NOT DEFINED QT_AUTODETECT_ANDROID)
+    if(DEFINED CMAKE_TOOLCHAIN_FILE AND NOT DEFINED QT_AUTODETECT_ANDROID
+            AND NOT QT_BUILD_STANDALONE_TESTS)
 
         file(READ ${CMAKE_TOOLCHAIN_FILE} toolchain_file_content OFFSET 0 LIMIT 80)
         string(FIND ${toolchain_file_content} "The Android Open Source Project" find_result REVERSE)
@@ -31,7 +34,7 @@ function(qt_auto_detect_android)
 endfunction()
 
 function(qt_auto_detect_vpckg)
-    if(DEFINED ENV{VCPKG_ROOT})
+    if(DEFINED ENV{VCPKG_ROOT} AND NOT QT_BUILD_STANDALONE_TESTS)
         set(vcpkg_toolchain_file "$ENV{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake")
         get_filename_component(vcpkg_toolchain_file "${vcpkg_toolchain_file}" ABSOLUTE)
 
@@ -49,6 +52,10 @@ function(qt_auto_detect_vpckg)
             message(STATUS "Using vcpkg triplet ${VCPKG_TARGET_TRIPLET}")
         endif()
         unset(vcpkg_toolchain_file)
+        message(STATUS "CMAKE_TOOLCHAIN_FILE is: ${CMAKE_TOOLCHAIN_FILE}")
+        if(DEFINED VCPKG_CHAINLOAD_TOOLCHAIN_FILE)
+            message(STATUS "VCPKG_CHAINLOAD_TOOLCHAIN_FILE is: ${VCPKG_CHAINLOAD_TOOLCHAIN_FILE}")
+        endif()
     endif()
 endfunction()