Allow building the tests directory as a standalone CMake project

At the moment, Coin builds tests as a separate qmake invocation
against an installed Qt. We need to support the same with CMake.

Change the tests subdirectory to be a standalone CMake project when
CMake does not detect an existing QtTest target while processing the
subdirectory. If the target exists, it means we are building the whole
repo, if the target does not exist, we need to call find_package
to find the installed Qt.

Refactor and move around a few things to make standalone tests build
successfully:
- add a new macro to set up paths to find QtSetup
- add a new macro to find all macOS frameworks
- add a new macro to set up building tests
- add a new macro that actually builds the tests
- export the INSTALL_CMAKE_NAMESPACE value into the BuildInternals
  Config file
- export the CMAKE_BUILD_TYPE value, because a test project doesn't
  have a .git subdir and thus defaults to be built in Release
  mode, even though qtbase might have been built in Debug, so to
  avoid the mixing, the propagate the build type
- stop overriding INSTALL_CMAKE_NAMESPACE and
  QT_CMAKE_EXPORT_NAMESPACE inside QtSetup if they are set, because
  the tests project doesn't specify a major version, and if we
  override the values, the moc / uic targets don't get the correct
  major version prefix and configuration fails

Change-Id: Ibdb03687302567fe325a15f6d1cb922c76240675
Fixes: QTBUG-75090
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 27 insertions, 8 deletions

diff --git a/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake b/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake
index 767a9dc45f..6f0708bd80 100644
--- a/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake
+++ b/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake
@@ -12,18 +12,22 @@ if(EXISTS "${CMAKE_CURRENT_LIST_DIR}/QtBuildInternalsExtra.cmake")
     include(${CMAKE_CURRENT_LIST_DIR}/QtBuildInternalsExtra.cmake)
 endif()
 
+macro(qt_set_up_build_internals_paths)
+    # Set up the paths for the modules.
+    set(QT_CMAKE_MODULE_PATH "${QT_BUILD_INTERNALS_PATH}/../${QT_CMAKE_EXPORT_NAMESPACE}")
+    list(APPEND CMAKE_MODULE_PATH ${QT_CMAKE_MODULE_PATH})
+
+    # If the repo has its own cmake modules, include those in the module path.
+    if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+        list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+    endif()
+endmacro()
+
 macro(qt_build_repo_begin)
     if(${ARGC} EQUAL 1 AND "${ARGV0}" STREQUAL "SKIP_CMAKE_MODULE_PATH_ADDITION")
         # No-op.
     else()
-        # Set up the paths for the modules.
-        set(QT_CMAKE_MODULE_PATH "${QT_BUILD_INTERNALS_PATH}/../${QT_CMAKE_EXPORT_NAMESPACE}")
-        list(APPEND CMAKE_MODULE_PATH ${QT_CMAKE_MODULE_PATH})
-
-        # If the repo has its own cmake modules, include those in the module path.
-        if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
-            list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
-        endif()
+        qt_set_up_build_internals_paths()
     endif()
 
     # Qt specific setup common for all modules:
@@ -73,3 +77,18 @@ macro(qt_build_repo)
 
     qt_build_repo_end()
 endmacro()
+
+macro(qt_set_up_standalone_tests_build)
+    qt_set_up_build_internals_paths()
+    include(QtSetup)
+    qt_find_apple_system_frameworks()
+endmacro()
+
+macro(qt_build_tests)
+    if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/auto/CMakeLists.txt")
+        add_subdirectory(auto)
+    endif()
+    if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/benchmarks/CMakeLists.txt")
+        add_subdirectory(benchmarks)
+    endif()
+endmacro()