Non-portable or problematic tests in qtbase test suite

;; The tests expect to find the modules provided by this
;; package; extend the environment variables needed to do so.
(setenv "CMAKE_PREFIX_PATH"
        (string-append #$output
                       ":" (getenv "CMAKE_PREFIX_PATH")))
(setenv "QMAKEPATH" (string-append #$output "/lib/qt6"))
(setenv "QML2_IMPORT_PATH"
        (string-append #$output "/lib/qt6/qml"))
(setenv "QT_PLUGIN_PATH"
        (string-append #$output "/lib/qt6/plugins"))
(setenv "QT_QPA_PLATFORM" "offscreen")
;; Skip tests known to fail on GNU/Linux, in a CI context or
;; due to bitness (see: https://code.qt.io/cgit/qt/qtbase.git
;; /tree/src/testlib/qtestblacklist.cpp).
(setenv "QTEST_ENVIRONMENT" "linux ci 32bit")
(setenv "HOME" "/tmp") ;some tests require a writable HOME
(invoke
 "xvfb-run" "ctest" "--output-on-failure"
 "-j" (if parallel-tests?
          (number->string (parallel-job-count))
          "1")
 "-E"                 ;disable problematic tests
 (string-append
  "("
  (string-join
   (list
    ;; The 'tst_moc' test fails with "'fi.exists()' returned FALSE".
    "tst_moc"
    ;; The 'test_rcc' test fails on a comparison:
    ;; <<<<<< actual
    ;; 0x0,0x0,0x0,0x0,0x0,0x0,0x3,0xe8,
    ;; ======
    ;; 0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,
    ;; >>>>>> expected
    "tst_rcc"
    ;; The 'tst_qtemporarydir' and 'tst_qtemporaryfile'
    ;; tests depend on '/home' not being writable.
    "tst_qtemporarydir"
    "tst_qtemporaryfile"
    ;; The 'tst_qdir' compares two directories which are
    ;; unexpectedly different when inside the build
    ;; container.
    "tst_qdir"
    ;; This checks the last modified time of '/', and fails
    ;; because Epoch 0 is considered to be invalid.
    "tst_qresourceengine"
    ;; The 'tst_qfilesystemwatcher' installs a watcher on
    ;; '/home', which doesn't exist in the build container.
    "tst_qfilesystemwatcher"
    ;; The 'mockplugins' test fail following error: "Unknown
    ;; platform linux-g++", and the other plugin tests
    ;; depend on it.
    "mockplugins"
    "test_plugin_flavor.*"
    ;; The 'test_import_plugins' fails with "Could NOT find
    ;; Qt6MockPlugins1".
    "test_import_plugins"
    ;; The 'tst_QTimeZone::systemZone' validates the
    ;; currently set timezone and fails.
    "tst_qtimezone"
    ;; The 'tst_qdatetime' fails with:
    ;; FAIL!  : tst_QDateTime::offsetFromUtc() Compared values are not the same
    ;; Actual   (dt5.offsetFromUtc()): 0
    ;; Expected (46800)              : 46800
    "tst_qdatetime"
    ;; The 'tst_QSettings::fromFile' assumes the data
    ;; location to be relative to the root directory and
    ;; fails.
    "tst_qsettings"
    ;; The 'tst_qaddpreroutine',
    ;; 'test_generating_cpp_exports' and
    ;; 'test_static_resources' tests fail with: "Unknown
    ;; platform linux-g++.
    "tst_qaddpreroutine"
    "test_generating_cpp_exports"
    "test_static_resources"
    ;; The 'tst_qfile' fails since there is no /home in the
    ;; build container.
    "tst_qfile"
    ;; The 'tst_QGlyphRun::mixedScripts' test fails with:
    ;; Actual   (glyphRuns.size()): 1
    ;; Expected (2)               : 2
    "tst_qglyphrun"
    ;; The 'tst_qx11info' test fails with "Internal error:
    ;; QPA plugin doesn't implement generatePeekerId",
    ;; likely requires a real display.
    "tst_qx11info"
    ;; The 'tst_qgraphicswidget' test fails because "This
    ;; plugin does not support propagateSizeHints".
    "tst_qgraphicswidget"
    ;; The 'tst_qdnslookup' test requires networking.
    "tst_qdnslookup"
    ;; The 'tst_qcompleter' and 'tst_QFiledialog::completer'
    ;; attempt to complete paths they assume exist, such as
    ;; "/home", "/etc" or "/root" and fail.
    "tst_qcompleter"
    "tst_qfiledialog") "|")
  ")"))