Add AccountAttributes serialization test

service/src/test/java/org/whispersystems/textsecuregcm/entities/AccountAttributesTest.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.entities;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.util.Base64;
+import org.junit.jupiter.api.Test;
+import org.whispersystems.textsecuregcm.util.SystemMapper;
+import org.whispersystems.textsecuregcm.util.TestRandomUtil;
+
+class AccountAttributesTest {
+
+  private static final ObjectMapper mapper = SystemMapper.jsonMapper();
+
+
+  @Test
+  void testSerializationDeserialization() throws Exception {
+
+    final String originalJson = testJson();
+
+    final AccountAttributes attributes = mapper.readValue(originalJson, AccountAttributes.class);
+
+    assertEquals(originalJson, mapper.writerWithDefaultPrettyPrinter().writeValueAsString(attributes));
+  }
+
+
+  private static String testJson() {
+
+    return String.format("""
+        {
+          "fetchesMessages" : false,
+          "registrationId" : 123,
+          "name" : "%s",
+          "registrationLock" : null,
+          "unidentifiedAccessKey" : "%s",
+          "unrestrictedUnidentifiedAccess" : false,
+          "capabilities" : {
+            "storage" : true
+          },
+          "discoverableByPhoneNumber" : true,
+          "recoveryPassword" : "%s",
+          "pniRegistrationId" : 456
+        }
+        """,
+        Base64.getEncoder().withoutPadding().encodeToString(TestRandomUtil.nextBytes(128)), // name
+        Base64.getEncoder().encodeToString(TestRandomUtil.nextBytes(16)), // unidentifiedAccessKey
+        Base64.getEncoder().encodeToString(TestRandomUtil.nextBytes(32)) // recoveryPassword
+    ).trim();
+
+  }
+
+
+}