fix: equals and hashcode of several classes

Signed-off-by: christian.lutnik <[email protected]>

Author: chrfwow

src/main/java/dev/openfeature/sdk/ImmutableStructure.java

@@ -70,12 +70,14 @@ private static Map<String, Value> copyAttributes(Map<String, Value> in) {
 
     private static Map<String, Value> copyAttributes(Map<String, Value> in, String targetingKey) {
         Map<String, Value> copy = new HashMap<>();
-        for (Entry<String, Value> entry : in.entrySet()) {
-            copy.put(
-                    entry.getKey(),
-                    Optional.ofNullable(entry.getValue())
-                            .map((Value val) -> val.clone())
-                            .orElse(null));
+        if (in != null) {
+            for (Entry<String, Value> entry : in.entrySet()) {
+                copy.put(
+                        entry.getKey(),
+                        Optional.ofNullable(entry.getValue())
+                                .map((Value val) -> val.clone())
+                                .orElse(null));
+            }
         }
         if (targetingKey != null) {
             copy.put(EvaluationContext.TARGETING_KEY, new Value(targetingKey));

src/test/java/dev/openfeature/sdk/ImmutableStructureTest.java

@@ -185,4 +185,16 @@ void equalImmutableStructuresAreEqual() {
 
         assertEquals(structure1, structure2);
     }
+
+    @Test
+    void emptyImmutableStructureIsEmpty() {
+        ImmutableStructure m1 = new ImmutableStructure();
+        assertTrue(m1.isEmpty());
+    }
+
+    @Test
+    void immutableStructureWithNullAttributesIsEmpty() {
+        ImmutableStructure m1 = new ImmutableStructure(null);
+        assertTrue(m1.isEmpty());
+    }
 }

src/test/java/dev/openfeature/sdk/MutableStructureTest.java

@@ -1,15 +1,26 @@
 package dev.openfeature.sdk;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotEquals;
-
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.*;
+
 class MutableStructureTest {
 
+    @Test
+    void emptyMutableStructureIsEmpty() {
+        MutableStructure m1 = new MutableStructure();
+        assertTrue(m1.isEmpty());
+    }
+
+    @Test
+    void mutableStructureWithNullBackingStructureIsEmpty() {
+        MutableStructure m1 = new MutableStructure(null);
+        assertTrue(m1.isEmpty());
+    }
+
     @Test
     void unequalMutableStructuresAreNotEqual() {
         MutableStructure m1 = new MutableStructure();