QQmlEngine: Add method to explicitly capture a property

Also, use that method to capture the uiLanguage notify signal.
Previously the wrong signal was captured. The test still happened to
pass because we manually re-evaluated all bindings when the uiLanguage
property changed. Add a test which avoid that.

Change-Id: I3961b60b365a8705930936f20881421bd4ceffe5
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 33 insertions, 20 deletions

diff --git a/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp b/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp
index ff8d6e2b2c..1e9b6434c4 100644
--- a/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp
+++ b/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp
@@ -1195,34 +1195,47 @@ void tst_qqmlengine::createComponentOnSingletonDestruction()
 
 void tst_qqmlengine::uiLanguage()
 {
-    QQmlEngine engine;
+    {
+        QQmlEngine engine;
 
-    QObject::connect(&engine, &QJSEngine::uiLanguageChanged, [&engine]() {
-        engine.retranslate();
-    });
+        QObject::connect(&engine, &QJSEngine::uiLanguageChanged, [&engine]() {
+            engine.retranslate();
+        });
 
-    QSignalSpy uiLanguageChangeSpy(&engine, SIGNAL(uiLanguageChanged()));
+        QSignalSpy uiLanguageChangeSpy(&engine, SIGNAL(uiLanguageChanged()));
 
-    QQmlComponent component(&engine, testFileUrl("uiLanguage.qml"));
+        QQmlComponent component(&engine, testFileUrl("uiLanguage.qml"));
 
-    QTest::ignoreMessage(QtMsgType::QtWarningMsg, (component.url().toString() + ":2:1: QML QtObject: Binding loop detected for property \"textToTranslate\"").toLatin1());
-    QScopedPointer<QObject> object(component.create());
-    QVERIFY(!object.isNull());
+        QTest::ignoreMessage(QtMsgType::QtWarningMsg, (component.url().toString() + ":2:1: QML QtObject: Binding loop detected for property \"textToTranslate\"").toLatin1());
+        QScopedPointer<QObject> object(component.create());
+        QVERIFY(!object.isNull());
 
-    QVERIFY(engine.uiLanguage().isEmpty());
-    QCOMPARE(object->property("numberOfTranslationBindingEvaluations").toInt(), 1);
+        QVERIFY(engine.uiLanguage().isEmpty());
+        QCOMPARE(object->property("numberOfTranslationBindingEvaluations").toInt(), 1);
 
-    QTest::ignoreMessage(QtMsgType::QtWarningMsg, (component.url().toString() + ":2:1: QML QtObject: Binding loop detected for property \"textToTranslate\"").toLatin1());
-    engine.setUiLanguage("TestLanguage");
-    QCOMPARE(object->property("numberOfTranslationBindingEvaluations").toInt(), 2);
-    QCOMPARE(object->property("chosenLanguage").toString(), "TestLanguage");
+        QTest::ignoreMessage(QtMsgType::QtWarningMsg, (component.url().toString() + ":2:1: QML QtObject: Binding loop detected for property \"textToTranslate\"").toLatin1());
+        engine.setUiLanguage("TestLanguage");
+        QCOMPARE(object->property("numberOfTranslationBindingEvaluations").toInt(), 2);
+        QCOMPARE(object->property("chosenLanguage").toString(), "TestLanguage");
 
+        QTest::ignoreMessage(QtMsgType::QtWarningMsg, (component.url().toString() + ":2:1: QML QtObject: Binding loop detected for property \"textToTranslate\"").toLatin1());
+        engine.evaluate("Qt.uiLanguage = \"anotherLanguage\"");
+        QCOMPARE(engine.uiLanguage(), QString("anotherLanguage"));
+        QCOMPARE(object->property("numberOfTranslationBindingEvaluations").toInt(), 3);
+        QCOMPARE(object->property("chosenLanguage").toString(), "anotherLanguage");
+    }
+
+    {
+        QQmlEngine engine;
+        QQmlComponent component(&engine, testFileUrl("uiLanguage.qml"));
 
-    QTest::ignoreMessage(QtMsgType::QtWarningMsg, (component.url().toString() + ":2:1: QML QtObject: Binding loop detected for property \"textToTranslate\"").toLatin1());
-    engine.evaluate("Qt.uiLanguage = \"anotherLanguage\"");
-    QCOMPARE(engine.uiLanguage(), QString("anotherLanguage"));
-    QCOMPARE(object->property("numberOfTranslationBindingEvaluations").toInt(), 3);
-    QCOMPARE(object->property("chosenLanguage").toString(), "anotherLanguage");
+        QTest::ignoreMessage(QtMsgType::QtWarningMsg, (component.url().toString() + ":2:1: QML QtObject: Binding loop detected for property \"textToTranslate\"").toLatin1());
+        QScopedPointer<QObject> object(component.create());
+        QVERIFY(!object.isNull());
+
+        engine.setUiLanguage("TestLanguage");
+        QCOMPARE(object->property("chosenLanguage").toString(), "TestLanguage");
+    }
 }
 
 QTEST_MAIN(tst_qqmlengine)