QFileDialog: Stabilize tests.

The init()/cleanup() code in tst_qfiledialog and tst_qfiledialog2
currently differs and fails to clean up the settings file
since it only removes the legacy settings under the Qt group
and instantiates a new QFileDialog while the QSettings class
is still in scope. Also, it has no means of clearing the
setLastVisitedDirectory(), which causes the
tst_QFiledialog::completer() and tst_QFiledialog::history() tests
to interfere, leaving the settings in an invalid state.
tst_qfiledialog2 does not use QStandardPaths::setTestModeEnabled(().

- Ensure the last visited URL is always clean by
  making QFileDialogPrivate::setLastVisitedDirectory()
  static and calling it from init().
- Introduce a cleanupSettingsFile() function to the tests that
  cleans both groups and call it from initTestCase() and cleanup()
  to ensure a clean state.
- Add QStandardPaths::setTestModeEnabled() to tst_qfiledialog2.

Fixes sporadic test fails when executing
tst_QFiledialog::completer() and tst_QFiledialog::history()
in a sequence.

Task-number: QTBUG-45764
Change-Id: I24de3caabf77be067b385d64ff11b7a07fe12b72
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

2 files changed, 3 insertions, 3 deletions

diff --git a/src/widgets/dialogs/qfiledialog.cpp b/src/widgets/dialogs/qfiledialog.cpp
index 9e5548ab4c..8590467abc 100644
--- a/src/widgets/dialogs/qfiledialog.cpp
+++ b/src/widgets/dialogs/qfiledialog.cpp
@@ -906,7 +906,7 @@ void QFileDialog::setDirectory(const QString &directory)
         return;
 
     QUrl newDirUrl = QUrl::fromLocalFile(newDirectory);
-    d->setLastVisitedDirectory(newDirUrl);
+    QFileDialogPrivate::setLastVisitedDirectory(newDirUrl);
 
     d->options->setInitialDirectory(QUrl::fromLocalFile(directory));
     if (!d->usingWidgets()) {
@@ -967,7 +967,7 @@ void QFileDialog::setDirectoryUrl(const QUrl &directory)
     if (!directory.isValid())
         return;
 
-    d->setLastVisitedDirectory(directory);
+    QFileDialogPrivate::setLastVisitedDirectory(directory);
     d->options->setInitialDirectory(directory);
 
     if (d->nativeDialogInUse)
diff --git a/src/widgets/dialogs/qfiledialog_p.h b/src/widgets/dialogs/qfiledialog_p.h
index 8a10896966..f610e46f83 100644
--- a/src/widgets/dialogs/qfiledialog_p.h
+++ b/src/widgets/dialogs/qfiledialog_p.h
@@ -187,7 +187,7 @@ public:
 #endif
 
     bool restoreWidgetState(QStringList &history, int splitterPosition);
-    void setLastVisitedDirectory(const QUrl &dir);
+    static void setLastVisitedDirectory(const QUrl &dir);
     void retranslateWindowTitle();
     void retranslateStrings();
     void emitFilesSelected(const QStringList &files);