Consider QObject could be null in CSlot

src/blackmisc/slot.h

@@ -62,13 +62,13 @@ namespace BlackMisc
         //! True if the slot can be called, false if it is empty.
         operator bool() const
         {
-            return !this->isEmpty();
+            return !this->isEmpty() && !this->hasNullObject();
         }
 
-        //! True if the slot is empty, false if it can be called.
+        //! True if the slot is empty or object is null, false if it can be called.
         bool operator !() const
         {
-            return this->isEmpty();
+            return this->isEmpty() || this->hasNullObject();
         }
 
         //! True if the slot is empty, false if it can be called.
@@ -77,6 +77,12 @@ namespace BlackMisc
             return ! m_function;
         }
 
+        //! True if the object is null
+        bool hasNullObject() const
+        {
+            return m_object.isNull();
+        }
+
     private:
         QPointer<QObject> m_object;
         std::function<R(Args...)> m_function;

tests/blackmisc/testblackmiscmain.cpp

@@ -23,6 +23,7 @@
 #include "testlibrarypath.h"
 #include "testmath.h"
 #include "testphysicalquantities.h"
+#include "testslot.h"
 #include "testvaluecache.h"
 #include "testvariantandmap.h"
 #include "testweather.h"
@@ -45,6 +46,7 @@ namespace BlackMiscTest
             CTestVariantAndMap variantAndMap;
             CTestInput inputTests;
             CTestIdentifier identifierTests;
+            CTestSlot slotTests;
             CTestValueCache valueCacheTests;
             CTestWeather weatherTests;
             CTestMath mathTests;
@@ -56,6 +58,7 @@ namespace BlackMiscTest
             status |= QTest::qExec(&containerTests, argc, argv);
             status |= QTest::qExec(&variantAndMap, argc, argv);
             status |= QTest::qExec(&inputTests, argc, argv);
+            status |= QTest::qExec(&slotTests, argc, argv);
             status |= QTest::qExec(&valueCacheTests, argc, argv);
             status |= QTest::qExec(&weatherTests, argc, argv);
             status |= QTest::qExec(&mathTests, argc, argv);

tests/blackmisc/testslot.cpp

@@ -0,0 +1,42 @@
+/* Copyright (C) 2016
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
+ * including this file, may be copied, modified, propagated, or distributed except according to the terms
+ * contained in the LICENSE file.
+ */
+
+//! \cond PRIVATE_TESTS
+
+/*!
+ * \file
+ * \ingroup testblackmisc
+ */
+
+#include "testslot.h"
+#include "blackmisc/slot.h"
+
+#include <QTest>
+
+using namespace BlackMisc;
+
+namespace BlackMiscTest
+{
+
+    void CTestSlot::slotBasics()
+    {
+        QObject *obj = new QObject(this);
+        CSlot<void(const QString &)> slot1 = { obj, &QObject::setObjectName };
+        QVERIFY2(slot1, "Slot has valid object and function - can be called.");
+
+        CSlot<void(const QString &)> slot2 = { static_cast<QObject*>(nullptr), &QObject::setObjectName };
+        QVERIFY2(!slot2, "Slot has an invalid pointer - cannot be called.");
+
+        CSlot<void(const QString &)> slot3;
+        QVERIFY2(!slot3, "Slot has an invalid pointer and invalid function - cannot be called.");
+    }
+
+} // namespace
+
+//! \endcond

tests/blackmisc/testslot.h

@@ -0,0 +1,43 @@
+/* Copyright (C) 2016
+ * swift project community / contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
+ * including this file, may be copied, modified, propagated, or distributed except according to the terms
+ * contained in the LICENSE file.
+ */
+
+#ifndef BLACKMISCTEST_TESTSLOT_H
+#define BLACKMISCTEST_TESTSLOT_H
+
+//! \cond PRIVATE_TESTS
+
+/*!
+ * \file
+ * \ingroup testblackmisc
+ */
+
+#include <QObject>
+
+namespace BlackMiscTest
+{
+
+    //! CSlot tests
+    class CTestSlot : public QObject
+    {
+        Q_OBJECT
+
+    public:
+        //! Standard test case constructor
+        explicit CTestSlot(QObject *parent = nullptr) : QObject(parent) {}
+
+    private slots:
+        //! Basic unit tests for CSlot
+        void slotBasics();
+    };
+
+} // namespace
+
+//! \endcond
+
+#endif // guard