Improves code coverage

Signed-off-by: Peter Alfonsi <[email protected]>

server/src/main/java/org/opensearch/common/cache/ICacheKey.java

@@ -57,7 +57,16 @@ public boolean equals(Object o) {
             return false;
         }
         ICacheKey other = (ICacheKey) o;
-        return key.equals(other.key) && dimensions.equals(other.dimensions);
+        if (!dimensions.equals(other.dimensions)) {
+            return false;
+        }
+        if (this.key == null && other.key == null) {
+            return true;
+        }
+        if (this.key == null || other.key == null) {
+            return false;
+        }
+        return this.key.equals(other.key);
     }
 
     @Override

server/src/test/java/org/opensearch/common/cache/serializer/ICacheKeySerializerTests.java

@@ -70,8 +70,17 @@ public void testHashCodes() throws Exception {
         ICacheKey<String> key1 = new ICacheKey<>("key", List.of("dimension_value"));
         ICacheKey<String> key2 = new ICacheKey<>("key", List.of("dimension_value"));
 
+        ICacheKey<String> key3 = new ICacheKey<>(null, List.of("dimension_value"));
+        ICacheKey<String> key4 = new ICacheKey<>(null, List.of("dimension_value"));
+
         assertEquals(key1, key2);
         assertEquals(key1.hashCode(), key2.hashCode());
+
+        assertEquals(key3, key4);
+        assertEquals(key3.hashCode(), key4.hashCode());
+
+        assertNotEquals(key1, key3);
+        assertNotEquals("string", key3);
     }
 
     public void testNullInputs() throws Exception {

server/src/test/java/org/opensearch/common/cache/stats/ImmutableCacheStatsTests.java

@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.cache.stats;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+public class ImmutableCacheStatsTests extends OpenSearchTestCase {
+    public void testSerialization() throws Exception {
+        ImmutableCacheStats immutableCacheStats = new ImmutableCacheStats(1, 2, 3, 4, 5);
+        BytesStreamOutput os = new BytesStreamOutput();
+        immutableCacheStats.writeTo(os);
+        BytesStreamInput is = new BytesStreamInput(BytesReference.toBytes(os.bytes()));
+        ImmutableCacheStats deserialized = new ImmutableCacheStats(is);
+
+        assertEquals(immutableCacheStats, deserialized);
+    }
+
+    public void testAddSnapshots() throws Exception {
+        ImmutableCacheStats ics1 = new ImmutableCacheStats(1, 2, 3, 4, 5);
+        ImmutableCacheStats ics2 = new ImmutableCacheStats(6, 7, 8, 9, 10);
+        ImmutableCacheStats expected = new ImmutableCacheStats(7, 9, 11, 13, 15);
+        assertEquals(expected, ImmutableCacheStats.addSnapshots(ics1, ics2));
+    }
+
+    public void testEqualsAndHash() throws Exception {
+        ImmutableCacheStats ics1 = new ImmutableCacheStats(1, 2, 3, 4, 5);
+        ImmutableCacheStats ics2 = new ImmutableCacheStats(1, 2, 3, 4, 5);
+        ImmutableCacheStats ics3 = new ImmutableCacheStats(0, 2, 3, 4, 5);
+
+        assertEquals(ics1, ics2);
+        assertNotEquals(ics1, ics3);
+        assertNotEquals(ics1, null);
+        assertNotEquals(ics1, "string");
+
+        assertEquals(ics1.hashCode(), ics2.hashCode());
+        assertNotEquals(ics1.hashCode(), ics3.hashCode());
+    }
+}