Hotfix for DD abstraction layer: copy and paste mistake in operator !\= is now fixed.

Former-commit-id: b815b7d7e8

src/storage/dd/CuddDd.cpp

@@ -16,7 +16,7 @@ namespace storm {
         }
         
         bool Dd<DdType::CUDD>::operator!=(Dd<DdType::CUDD> const& other) const {
-            return this->cuddAdd == other.getCuddAdd();
+            return this->cuddAdd != other.getCuddAdd();
         }
         
         Dd<DdType::CUDD> Dd<DdType::CUDD>::operator+(Dd<DdType::CUDD> const& other) const {

test/functional/storage/CuddDdTest.cpp

@@ -119,6 +119,9 @@ TEST(CuddDd, OperatorTest) {
     EXPECT_TRUE(manager->getZero() == manager->getZero());
     EXPECT_FALSE(manager->getZero() == manager->getOne());
 
+    EXPECT_FALSE(manager->getZero() != manager->getZero());
+    EXPECT_TRUE(manager->getZero() != manager->getOne());
+    
     storm::dd::Dd<storm::dd::DdType::CUDD> dd1 = manager->getOne();
     storm::dd::Dd<storm::dd::DdType::CUDD> dd2 = manager->getOne();
     storm::dd::Dd<storm::dd::DdType::CUDD> dd3 = dd1 + dd2;