Achieve 100% test coverage for de.rub.nds.modifiablevariable.length package

src/test/java/de/rub/nds/modifiablevariable/json/LengthFieldSerializationTest.java

@@ -0,0 +1,105 @@
+/*
+ * ModifiableVariable - A Variable Concept for Runtime Modifications
+ *
+ * Ruhr University Bochum, Paderborn University, Technology Innovation Institute, and Hackmanit GmbH
+ *
+ * Licensed under Apache License 2.0 http://www.apache.org/licenses/LICENSE-2.0
+ */
+package de.rub.nds.modifiablevariable.json;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import de.rub.nds.modifiablevariable.bytearray.ModifiableByteArray;
+import de.rub.nds.modifiablevariable.integer.IntegerAddModification;
+import de.rub.nds.modifiablevariable.length.ModifiableLengthField;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class LengthFieldSerializationTest {
+
+    private static final Logger LOGGER = LogManager.getLogger();
+    private static ObjectMapper mapper;
+
+    private ModifiableLengthField lengthField;
+    private ModifiableByteArray byteArray;
+
+    @BeforeAll
+    public static void setUpClass() {
+        mapper = new ObjectMapper();
+        mapper.registerModule(new ModifiableVariableModule());
+        mapper.setVisibility(ModifiableVariableModule.getFieldVisibilityChecker());
+    }
+
+    @BeforeEach
+    public void setUp() {
+        byteArray = new ModifiableByteArray();
+        byteArray.setOriginalValue(new byte[] {1, 2, 3, 4, 5});
+        lengthField = new ModifiableLengthField(byteArray);
+    }
+
+    @Test
+    public void testSerializeDeserializeSimple() throws Exception {
+        String jsonString = mapper.writeValueAsString(lengthField);
+        LOGGER.debug("Serialized JSON: {}", jsonString);
+
+        ModifiableLengthField deserialized =
+                mapper.readValue(jsonString, ModifiableLengthField.class);
+
+        assertNotNull(deserialized);
+        assertEquals(5, (int) deserialized.getOriginalValue());
+        assertEquals(5, (int) deserialized.getValue());
+    }
+
+    @Test
+    public void testSerializeDeserializeWithModification() throws Exception {
+        lengthField.setModifications(new IntegerAddModification(10));
+        assertEquals(15, (int) lengthField.getValue());
+
+        String jsonString = mapper.writeValueAsString(lengthField);
+        LOGGER.debug("Serialized JSON with modification: {}", jsonString);
+
+        ModifiableLengthField deserialized =
+                mapper.readValue(jsonString, ModifiableLengthField.class);
+
+        assertNotNull(deserialized);
+        assertEquals(5, (int) deserialized.getOriginalValue());
+        assertEquals(15, (int) deserialized.getValue());
+    }
+
+    @Test
+    public void testSerializeDeserializeWithNullByteArrayValue() throws Exception {
+        byteArray.setOriginalValue(null);
+        assertNull(lengthField.getOriginalValue());
+        assertNull(lengthField.getValue());
+
+        String jsonString = mapper.writeValueAsString(lengthField);
+        LOGGER.debug("Serialized JSON with null byte array: {}", jsonString);
+
+        ModifiableLengthField deserialized =
+                mapper.readValue(jsonString, ModifiableLengthField.class);
+
+        assertNotNull(deserialized);
+        assertNull(deserialized.getOriginalValue());
+        assertNull(deserialized.getValue());
+    }
+
+    @Test
+    public void testSerializedFieldReferencesArePreserved() throws Exception {
+        lengthField.setModifications(new IntegerAddModification(3));
+
+        String jsonString = mapper.writeValueAsString(lengthField);
+        ModifiableLengthField deserialized =
+                mapper.readValue(jsonString, ModifiableLengthField.class);
+
+        byteArray.setOriginalValue(new byte[] {1, 2});
+        assertEquals(2, (int) lengthField.getOriginalValue());
+        assertEquals(5, (int) lengthField.getValue());
+
+        assertEquals(5, (int) deserialized.getOriginalValue());
+        assertEquals(8, (int) deserialized.getValue());
+    }
+}

src/test/java/de/rub/nds/modifiablevariable/length/ModifiableLengthFieldTest.java

@@ -544,4 +544,38 @@ void testReferenceWithNoOriginalValue() {
                 "Original value should still be array length");
         assertEquals(13, (int) lengthField.getValue(), "Value should include modification");
     }
+
+    /** Test edge case: comparing fields where one has modifications resulting in null */
+    @Test
+    public void testEqualsWithOneNullValue() {
+        // Create two fields with the same reference
+        ModifiableByteArray sharedArray = new ModifiableByteArray();
+        sharedArray.setOriginalValue(new byte[] {1, 2, 3, 4});
+
+        ModifiableLengthField field1 = new ModifiableLengthField(sharedArray);
+        ModifiableLengthField field2 = new ModifiableLengthField(sharedArray);
+
+        // Create a special modification that returns null
+        class NullResultModification extends IntegerAddModification {
+            public NullResultModification() {
+                super(0);
+            }
+
+            @Override
+            protected Integer modifyImplementationHook(Integer input) {
+                return null;
+            }
+        }
+
+        // Apply null modification to only one field
+        field1.setModifications(new NullResultModification());
+
+        // field1.getValue() is null, field2.getValue() is 4
+        assertNull(field1.getValue());
+        assertEquals(4, (int) field2.getValue());
+
+        // They should not be equal
+        assertNotEquals(field1, field2);
+        assertNotEquals(field2, field1);
+    }
 }