Test QTRY_COMPARE() and expand testing of QTRY_VERIFY*()

In the process, simplify the latter while adding some actual
time-variation for the QTRY_* loop to navigate round - based on the
extendedcompare test's ClassWithDeferredSetter. Testing remains
primitive, but is at least a bit more thorough.

Pick-to: 6.4
Change-Id: I40be8fb485f3f18f0a4f4bc62ad36cccac691979
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>
Reviewed-by: Jason McDonald <macadder1@gmail.com>

1 files changed, 79 insertions, 6 deletions

diff --git a/tests/auto/testlib/selftests/cmptest/tst_cmptest.cpp b/tests/auto/testlib/selftests/cmptest/tst_cmptest.cpp
index 94c04157f2..072324880e 100644
--- a/tests/auto/testlib/selftests/cmptest/tst_cmptest.cpp
+++ b/tests/auto/testlib/selftests/cmptest/tst_cmptest.cpp
@@ -1,9 +1,9 @@
 // Copyright (C) 2016 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
 
-
-#include <QtCore/QCoreApplication>
 #include <QTest>
+#include <QtCore/QCoreApplication>
+#include <QtCore/QTimer>
 #ifdef QT_GUI_LIB
 #include <QtGui/QColor>
 #include <QtGui/QImage>
@@ -139,6 +139,7 @@ private slots:
     void compareQVector3D();
     void compareQVector4D();
 #endif
+    void tryCompare();
     void verify();
     void verify2();
     void tryVerify();
@@ -649,16 +650,88 @@ void tst_Cmptest::verify2()
     QVERIFY2(opaqueFunc() < 2, QByteArray::number(opaqueFunc()).constData());
 }
 
+class DeferredFlag : public QObject // Can't be const.
+{
+    Q_OBJECT
+    bool m_flag;
+public:
+    // A boolean that either starts out true or decays to true after 50 ms.
+    // However, that decay will only happen when the event loop is run.
+    explicit DeferredFlag(bool initial = false) : m_flag(initial)
+    {
+        if (!initial)
+            QTimer::singleShot(50, this, &DeferredFlag::onTimeOut);
+    }
+    explicit operator bool() const { return m_flag; }
+    bool operator!() const { return !m_flag; }
+    friend bool operator==(const DeferredFlag &a, const DeferredFlag &b)
+    {
+        return bool(a) == bool(b);
+    }
+public slots:
+    void onTimeOut() { m_flag = true; }
+};
+
+char *toString(const DeferredFlag &val)
+{
+    return qstrdup(bool(val) ? "DeferredFlag(true)" : "DeferredFlag(false)");
+}
+
+void tst_Cmptest::tryCompare()
+{
+    /* Note that expected values given as DeferredFlag() shall be re-evaluated
+       each time the comparison is checked, hence supply a fresh false instance,
+       that'll be discarded before it has a chance to decay, hence only compare
+       equal to a false instance. Do not replace them with a local variable
+       initialized to false, as it would (of course) decay.
+    */
+    DeferredFlag trueAlready(true);
+    {
+        DeferredFlag c;
+        // QTRY should check before looping, so be equal to the fresh false immediately.
+        QTRY_COMPARE(c, DeferredFlag());
+        // Given time, it'll end up equal to a true one.
+        QTRY_COMPARE(c, trueAlready);
+    }
+    {
+        DeferredFlag c;
+        QTRY_COMPARE_WITH_TIMEOUT(c, DeferredFlag(), 300);
+        QVERIFY(!c); // Instantly equal, so succeeded without delay.
+        QTRY_COMPARE_WITH_TIMEOUT(c, trueAlready, 200);
+        qInfo("Should now time out and fail");
+        QTRY_COMPARE_WITH_TIMEOUT(c, DeferredFlag(), 200);
+    }
+}
+
 void tst_Cmptest::tryVerify()
 {
-    QTRY_VERIFY(opaqueFunc() > 2);
-    QTRY_VERIFY_WITH_TIMEOUT(opaqueFunc() < 2, 1);
+    {
+        DeferredFlag c;
+        QTRY_VERIFY(!c);
+        QTRY_VERIFY(c);
+    }
+    {
+        DeferredFlag c;
+        QTRY_VERIFY_WITH_TIMEOUT(!c, 300);
+        QTRY_VERIFY_WITH_TIMEOUT(c, 200);
+        qInfo("Should now time out and fail");
+        QTRY_VERIFY_WITH_TIMEOUT(!c, 200);
+    }
 }
 
 void tst_Cmptest::tryVerify2()
 {
-    QTRY_VERIFY2(opaqueFunc() > 2, QByteArray::number(opaqueFunc()).constData());
-    QTRY_VERIFY2_WITH_TIMEOUT(opaqueFunc() < 2, QByteArray::number(opaqueFunc()).constData(), 1);
+    {
+        DeferredFlag c;
+        QTRY_VERIFY2(!c, "Failed to check before looping");
+        QTRY_VERIFY2(c, "Failed to trigger single-shot");
+    }
+    {
+        DeferredFlag c;
+        QTRY_VERIFY2_WITH_TIMEOUT(!c, "Failed to check before looping", 300);
+        QTRY_VERIFY2_WITH_TIMEOUT(c, "Failed to trigger single-shot", 200);
+        QTRY_VERIFY2_WITH_TIMEOUT(!c, "Should time out and fail", 200);
+    }
 }
 
 void tst_Cmptest::verifyExplicitOperatorBool()