CMake: Add option to run cmake build tests

Use "cmake -DBUILD_CMAKE_TESTING=ON" to enable running cmake build system
tests with ctest.

Change-Id: I0a32e2d1771c9bbb0df013d0d955a9b58b1d4b79
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

CMakeLists.txt

@@ -23,6 +23,9 @@ include(FeatureSummary)
 ## QtBase specific configure tests:
 include(QtBaseConfigureTests)
 
+## Build System tests:
+include(QtBaseCMakeTesting)
+
 ## Targets for global features, etc.:
 include(QtBaseGlobalTargets)
 

cmake/QtBaseCMakeTesting.cmake

@@ -0,0 +1,9 @@
+## Test the cmake build system:
+option(BUILD_CMAKE_TESTING "Build tests for the Qt build system" OFF)
+mark_as_advanced(BUILD_CMAKE_TESTING)
+
+if(BUILD_CMAKE_TESTING)
+    add_subdirectory("${PROJECT_SOURCE_DIR}/cmake/tests")
+endif()
+
+

cmake/tests/CMakeLists.txt

@@ -0,0 +1,25 @@
+# These macros are taken from the ECM:
+
+# a macro for tests that have a simple format where the name matches the
+# directory and project
+macro(add_test_variant NAME BASE COMMAND)
+    string(REPLACE "." "/" src_dir "${BASE}")
+    string(REPLACE "." "/" build_dir "${NAME}")
+    string(REGEX REPLACE "[^.]*\\." "" proj "${NAME}")
+    add_test("cmake_${NAME}" ${CMAKE_CTEST_COMMAND}
+        --build-and-test
+            "${CMAKE_CURRENT_SOURCE_DIR}/${src_dir}"
+            "${CMAKE_CURRENT_BINARY_DIR}/${build_dir}"
+        --build-two-config
+        --build-generator ${CMAKE_GENERATOR}
+        --build-makeprogram ${CMAKE_MAKE_PROGRAM}
+        --build-project ${proj}
+        ${${NAME}_EXTRA_OPTIONS}
+        --test-command ${COMMAND} ${ARGN})
+endmacro()
+
+macro(add_test_macro NAME)
+    add_test_variant("${NAME}" "${NAME}" ${ARGN})
+endmacro()
+
+add_test_macro(features features)

cmake/tests/features/CMakeLists.txt

@@ -40,3 +40,5 @@ include(QtPostProcess)
 
 ## Print a feature summary:
 feature_summary(WHAT PACKAGES_FOUND PACKAGES_NOT_FOUND FATAL_ON_MISSING_REQUIRED_PACKAGES)
+
+add_executable(features ../main.cpp)

cmake/tests/main.cpp

@@ -0,0 +1 @@
+int main(int argc, char** argv) { return 0; }