Tests: Add XCTest cases to cover output directory selection

Fixes: #21800

Tests/RunCMake/XcodeProject/RunCMakeTest.cmake

@@ -387,4 +387,30 @@ if(XCODE_VERSION VERSION_GREATER_EQUAL 8)
   XcodeRemoveExcessiveISystemSDK(iphoneos)
   XcodeRemoveExcessiveISystemSDK(iphonesimulator)
 endif()
+
+if (XCODE_VERSION VERSION_GREATER_EQUAL 7.3)
+  function(xctest_add_bundle_test SystemName SDK BuildSystemVersion ExpectedOutputDir)
+    set(RunCMake_TEST_BINARY_DIR
+      ${RunCMake_BINARY_DIR}/DeploymentTarget-${SystemName}-${SDK}-${BuildSystemVersion}-build)
+    set(RunCMake_TEST_OPTIONS
+      "-DCMAKE_SYSTEM_NAME=${SystemName}"
+      "-DCMAKE_OSX_SYSROOT=${SDK}"
+      "-DTEST_EXPECTED_OUTPUT_DIR=${ExpectedOutputDir}")
+    unset(RunCMake_GENERATOR_TOOLSET)
+    if(BuildSystemVersion)
+      set(RunCMake_GENERATOR_TOOLSET "buildsystem=${BuildSystemVersion}")
+    endif()
+    run_cmake(XCTestAddBundle)
+  endfunction()
+
+  if(XCODE_VERSION VERSION_GREATER_EQUAL 12)
+    xctest_add_bundle_test(Darwin macosx "1" "$<TARGET_BUNDLE_CONTENT_DIR:TestedApp>/PlugIns")
+    xctest_add_bundle_test(Darwin macosx "12" "$<TARGET_BUNDLE_CONTENT_DIR:TestedApp>/PlugIns")
+    xctest_add_bundle_test(iOS iphoneos "1" "$<TARGET_BUNDLE_CONTENT_DIR:TestedApp>/PlugIns")
+    xctest_add_bundle_test(iOS iphoneos "12" "$<TARGET_BUNDLE_CONTENT_DIR:TestedApp>")
+  else()
+    xctest_add_bundle_test(Darwin macosx "" "$<TARGET_BUNDLE_CONTENT_DIR:TestedApp>/PlugIns")
+    xctest_add_bundle_test(iOS iphoneos "" "$<TARGET_BUNDLE_CONTENT_DIR:TestedApp>/PlugIns")
+  endif()
+endif()
 # Please add macOS-only tests above before the device-specific tests.

Tests/RunCMake/XcodeProject/XCTestAddBundle.cmake

@@ -0,0 +1,17 @@
+enable_language(Swift)
+find_package(XCTest REQUIRED)
+
+add_executable(TestedApp MACOSX_BUNDLE EXCLUDE_FROM_ALL foo.swift)
+
+xctest_add_bundle(TestingAppBundle TestedApp foo.swift)
+
+get_target_property(_lib_output_dir TestingAppBundle LIBRARY_OUTPUT_DIRECTORY)
+
+if (NOT DEFINED TEST_EXPECTED_OUTPUT_DIR)
+    message(FATAL_ERROR "Testing variable TEST_EXPECTED_OUTPUT_DIR is not set")
+endif()
+
+if (NOT _lib_output_dir STREQUAL TEST_EXPECTED_OUTPUT_DIR)
+    message(SEND_ERROR "Property LIBRARY_OUTPUT_DIRECTORY is expected to be ${TEST_EXPECTED_OUTPUT_DIR} "
+        "but was ${_lib_output_dir}")
+endif()