F consolidation

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new/changed behavior? Which bug has been fixed? Are there related Issues?

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Test Environment

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• All automated tests pass
• Reference related Issues
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• All automated tests pass
• Up-to-date CHANGELOG.md
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test/test_data_type.cpp

@@ -48,6 +48,7 @@ TEST(test_data_type, test_atomic) {
   for (int i = 1; i < 6; i++) {
     Entity entity;
     entity.SetRole(Role::PROPERTY);
+    // the different AtomicDataType are associated with integers
     entity.SetDataType(static_cast<AtomicDataType>(i));
     EXPECT_TRUE(entity.GetDataType().IsAtomic());
     EXPECT_EQ(entity.GetDataType().AsAtomic(), static_cast<AtomicDataType>(i));
@@ -57,6 +58,7 @@ TEST(test_data_type, test_atomic) {
     entity.SetDataType(data_type);
 
     EXPECT_FALSE(data_type.IsReference());
+    EXPECT_EQ(data_type.AsReference().GetName(), std::basic_string<char>(""));
     EXPECT_FALSE(data_type.IsList());
     EXPECT_TRUE(data_type.IsAtomic());
     EXPECT_EQ(data_type.AsAtomic(), static_cast<AtomicDataType>(i));
@@ -95,6 +97,7 @@ TEST(test_data_type, test_list_of_atomic) {
     EXPECT_FALSE(data_type.IsAtomic());
     EXPECT_TRUE(data_type.IsList());
     const auto &list_data_type = data_type.AsList();
+    EXPECT_EQ(list_data_type.GetReferenceDataType().GetName(), std::basic_string<char>(""));
     EXPECT_TRUE(list_data_type.IsListOfAtomic());
     EXPECT_FALSE(list_data_type.IsListOfReference());
     EXPECT_EQ(list_data_type.GetAtomicDataType(),