Fix cppcheck warnings

Author: Your Name

test/testnonnullptr.cpp

@@ -52,13 +52,17 @@ class TestNonNullPtr : public TestFixture {
         const NonNullPtr<int> p(x);
         int* raw = p;
         ASSERT(raw == &x);
+        *raw = 2;
+        ASSERT_EQUALS(2, x);
     }
 
     void referenceConversion() const {
         int x = 1;
         const NonNullPtr<int> p(x);
         int& ref = p;
         ASSERT(&ref == &x);
+        ref = 2;
+        ASSERT_EQUALS(2, x);
     }
 
     void dereference() const {