add unit tests

Signed-off-by: Sandeep Kumawat <2025sandeepkumawat@gmail.com>

server/src/test/java/org/opensearch/common/blobstore/EncryptedBlobContainerTests.java

@@ -0,0 +1,41 @@
+
+/*
+ * 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.blobstore;
+
+import org.opensearch.common.crypto.CryptoHandler;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.HashMap;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class EncryptedBlobContainerTests extends OpenSearchTestCase {
+
+    public void testBlobContainerReadBlobWithMetadata() throws IOException {
+        BlobContainer blobContainer = mock(BlobContainer.class);
+        CryptoHandler cryptoHandler = mock(CryptoHandler.class);
+        EncryptedBlobContainer encryptedBlobContainer = new EncryptedBlobContainer(blobContainer, cryptoHandler);
+        InputStreamWithMetadata inputStreamWithMetadata = new InputStreamWithMetadata(
+            new ByteArrayInputStream(new byte[0]),
+            new HashMap<>()
+        );
+        when(blobContainer.readBlobWithMetadata("test")).thenReturn(inputStreamWithMetadata);
+        InputStream decrypt = new ByteArrayInputStream(new byte[2]);
+        when(cryptoHandler.createDecryptingStream(inputStreamWithMetadata.getInputStream())).thenReturn(decrypt);
+        InputStreamWithMetadata result = encryptedBlobContainer.readBlobWithMetadata("test");
+        assertEquals(result.getInputStream(), decrypt);
+        assertEquals(result.getMetadata(), inputStreamWithMetadata.getMetadata());
+    }
+
+}