Add operator bool() and test boolean checks

include/rcp.h

@@ -99,6 +99,11 @@ public:
     {
         return !ptr;
     }
+
+    operator bool() const
+    {
+        return ptr != nullptr;
+    }
 };
 
 #define rcp_managed_root(classname) \

test/tests.cpp

@@ -69,9 +69,18 @@ void test_dereference()
     assert((*mybase).y == 3);
 }
 
+void test_booleans()
+{
+    rcp<MyBase> mybase = MyBase::create(2, 3);
+    assert(mybase);
+    rcp<MyDerived> myderived;
+    assert(!myderived);
+}
+
 int main(int argc, char * argv[])
 {
     test_destructors_called();
     test_dereference();
+    test_booleans();
     return 0;
 }