Stabilize QFileSystemModel::dirsBeforeFiles test

Make the test operate in its own temporary directory, so that entries
left behind by other test functions don't impact this test.

Also, call QFileSystemModel::sort explicitly; it would otherwise only
be done once through a single-shot timer, and the test processes events
until the model is populated, which might not process that delayed
sorting. Since dirsBeforeFiles tests the sorting algorithm and not
the sorting logic, best to do this explicitly.

In case of sort failure, print diagnostics.

Done-with: Friedemann Kleint <Friedemann.Kleint@qt.io>
Fixes: QTBUG-75452
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
(cherry picked from commit 4e796e0b0dcf4c0848044471021db3afce16ee5d)
Change-Id: I144b68a17280a38cc7d6daf7ec343eea4453623d
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

1 files changed, 18 insertions, 10 deletions

diff --git a/tests/auto/widgets/dialogs/qfilesystemmodel/tst_qfilesystemmodel.cpp b/tests/auto/widgets/dialogs/qfilesystemmodel/tst_qfilesystemmodel.cpp
index 590b3502f1..e29a715617 100644
--- a/tests/auto/widgets/dialogs/qfilesystemmodel/tst_qfilesystemmodel.cpp
+++ b/tests/auto/widgets/dialogs/qfilesystemmodel/tst_qfilesystemmodel.cpp
@@ -1014,30 +1014,38 @@ void tst_QFileSystemModel::drives()
 
 void tst_QFileSystemModel::dirsBeforeFiles()
 {
-    QDir dir(flatDirTestPath);
+    auto diagnosticMsg = [](int row, const QFileInfo &left, const QFileInfo &right) -> QByteArray {
+        QString message;
+        QDebug(&message).noquote() << "Unexpected sort order at #" << row << ':' << left << right;
+        return message.toLocal8Bit();
+    };
+    QTemporaryDir testDir(flatDirTestPath);
+    QVERIFY2(testDir.isValid(), qPrintable(testDir.errorString()));
+    QDir dir(testDir.path());
 
     const int itemCount = 3;
     for (int i = 0; i < itemCount; ++i) {
         QLatin1Char c('a' + char(i));
         QVERIFY(dir.mkdir(c + QLatin1String("-dir")));
-        QFile file(flatDirTestPath + QLatin1Char('/') + c + QLatin1String("-file"));
+        QFile file(dir.filePath(c + QLatin1String("-file")));
         QVERIFY(file.open(QIODevice::ReadWrite));
         file.close();
     }
 
     QScopedPointer<QFileSystemModel> model(new QFileSystemModel);
-    QModelIndex root = model->setRootPath(flatDirTestPath);
+    QModelIndex root = model->setRootPath(dir.absolutePath());
     // Wait for model to be notified by the file system watcher
     QTRY_COMPARE(model->rowCount(root), 2 * itemCount);
-
-    // Ensure that no file occurs before any directory:
-    for (int i = 1; i < model->rowCount(root); ++i) {
+    // sort explicitly - dirs before files (except on macOS), and then by name
+    model->sort(0);
+    // Ensure that no file occurs before any directory (see QFileSystemModelSorter):
+    for (int i = 1, count = model->rowCount(root); i < count; ++i) {
+        const QFileInfo previous = model->fileInfo(model->index(i - 1, 0, root));
+        const QFileInfo current = model->fileInfo(model->index(i, 0, root));
 #ifndef Q_OS_MAC
-        QVERIFY(!(model->fileInfo(model->index(i - 1, 0, root)).isFile()
-                  && model->fileInfo(model->index(i, 0, root)).isDir()));
+        QVERIFY2(!(previous.isFile() && current.isDir()), diagnosticMsg(i, previous, current).constData());
 #else
-        QVERIFY(model->fileInfo(model->index(i - 1, 0, root)).fileName() <
-                model->fileInfo(model->index(i, 0, root)).fileName());
+        QVERIFY2(previous.fileName() < current.fileName(), diagnosticMsg(i, previous, current).constData());
 #endif
     }
 }