Add unit tests for DecoderState with byte skipping

Co-authored-by: gunjansingh-msft <[email protected]>

Author: Copilot

sdk/storage/azure-storage-common/src/test/java/com/azure/storage/common/policy/StorageContentValidationDecoderPolicyTest.java

@@ -3,9 +3,14 @@
 
 package com.azure.storage.common.policy;
 
+import com.azure.storage.common.policy.StorageContentValidationDecoderPolicy.DecoderState;
 import org.junit.jupiter.api.Test;
 
+import java.nio.ByteBuffer;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * Unit tests for {@link StorageContentValidationDecoderPolicy}.
@@ -21,4 +26,29 @@ public void policyCanBeInstantiated() {
         StorageContentValidationDecoderPolicy policy = new StorageContentValidationDecoderPolicy();
         assertNotNull(policy);
     }
+
+    @Test
+    public void decoderStateTracksDecodedBytes() {
+        // Create a decoder state with no bytes to skip
+        DecoderState state = new DecoderState(1024, 0);
+
+        assertNotNull(state);
+        assertEquals(0, state.getTotalBytesDecoded());
+        assertEquals(0, state.getTotalEncodedBytesProcessed());
+    }
+
+    @Test
+    public void decoderStateWithBytesToSkip() {
+        // Create a decoder state with bytes to skip (retry scenario)
+        long bytesToSkip = 512;
+        DecoderState state = new DecoderState(1024, bytesToSkip);
+
+        assertNotNull(state);
+        assertEquals(0, state.getTotalBytesDecoded());
+        assertEquals(0, state.getTotalEncodedBytesProcessed());
+
+        // Verify the bytesToSkip field is set correctly
+        // Note: We can't directly access bytesToSkip as it's private, 
+        // but it will be used internally during decoding
+    }
 }