To run it alone (working) ./Tools/Scripts/run-gtk-tests --flatpak-verbose --display-server=xvfb --release WebKitBuild/GTK/Release/bin/TestWebKitAPI/WebKit2Gtk/TestWebsiteData -p /webkit/WebKitWebsiteData/itp Removing the "-p /webkit..." parameters to run the full TestWebsiteData shows the failure: ERROR:../../Tools/TestWebKitAPI/Tests/WebKitGLib/TestWebsiteData.cpp:706:void testWebsiteDataITP(WebsiteDataTest*, gconstpointer): 'g_file_test(itpDirectory, G_FILE_TEST_IS_DIR)' should be FALSE This failure was introduced by r281886.