diff --git a/javatests/com/google/gitiles/ArchiveServletTest.java b/javatests/com/google/gitiles/ArchiveServletTest.java
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+++ b/javatests/com/google/gitiles/ArchiveServletTest.java
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+// Copyright (C) 2026 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gitiles;
+
+import static com.google.common.truth.Truth.assertThat;
+import static javax.servlet.http.HttpServletResponse.SC_OK;
+
+import com.google.common.net.HttpHeaders;
+import org.junit.Test;
+
+public class ArchiveServletTest extends ServletTest {
+
+  @Test
+  public void tarGzArchive_smokeTest() throws Exception {
+    // Create a commit on master so refs/heads/master exists and points to a tree.
+    repo.branch("master").commit().add("README.md", "hello\n").create();
+
+    FakeHttpServletResponse res =
+        buildResponse("/repo/+archive/refs/heads/master.tar.gz", /* queryString= */ null, SC_OK);
+
+    // Content-Type depends on ArchiveFormat mapping; be tolerant but ensure it's gzip-ish.
+    String contentType = res.getHeader(HttpHeaders.CONTENT_TYPE);
+    assertThat(contentType).isNotNull();
+    assertThat(contentType.toLowerCase()).contains("gzip");
+
+    // Content-Disposition should suggest a downloadable filename.
+    String cd = res.getHeader(HttpHeaders.CONTENT_DISPOSITION);
+    assertThat(cd).isNotNull();
+    assertThat(cd).contains("attachment");
+
+    // Be robust: Gitiles' filename includes the "revision name", which may be "master" or
+    // "refs/heads/master" depending on how the URL was formed/resolved.
+    assertThat(cd).contains("filename=");
+    assertThat(cd).contains("repo-");
+    assertThat(cd).contains("master");
+    assertThat(cd).contains(".tar.gz");
+
+    // Body should be non-empty. Note: FakeHttpServletResponse writes via a Writer (UTF-8),
+    // so binary bytes are not preserved; don't assert gzip magic bytes here.
+    byte[] body = res.getActualBody();
+    assertThat(body.length).isGreaterThan(20);
+  }
+}