diff --git a/backend-java/src/test/java/com/nanri/aiimage/modules/softwareversion/service/support/Task163Test.java b/backend-java/src/test/java/com/nanri/aiimage/modules/softwareversion/service/support/Task163Test.java
new file mode 100644
index 00000000..4cd9dc39
--- /dev/null
+++ b/backend-java/src/test/java/com/nanri/aiimage/modules/softwareversion/service/support/Task163Test.java
@@ -0,0 +1,77 @@
+package com.nanri.aiimage.modules.softwareversion.service.support;
+
+import com.nanri.aiimage.modules.softwareversion.service.support.PublicVersionLookup.WebVersion;
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/** task-163: module 09 公开版本契约测试(web_config 排序)。 */
+class Task163Test {
+
+    private WebVersion v(Long id, String version, String fileUrl, LocalDateTime at) {
+        return new WebVersion(id, version, fileUrl, at);
+    }
+
+    @Test
+    void test_task_163_normal_primary_path() {
+        WebVersion latest = PublicVersionLookup.selectLatest(List.of(
+                v(1L, "1.0.1", "https://a/1.zip", LocalDateTime.of(2026, 1, 1, 0, 0)),
+                v(2L, "1.0.2", "https://a/2.zip", LocalDateTime.of(2026, 1, 2, 0, 0))));
+        assertNotNull(latest);
+        assertEquals("1.0.2", latest.version());
+        assertEquals("https://a/2.zip", latest.fileUrl());
+    }
+
+    @Test
+    void test_task_163_normal_variant_input() {
+        WebVersion latest = PublicVersionLookup.selectLatest(List.of(
+                v(5L, "1.0.5", "u5", LocalDateTime.of(2026, 2, 2, 0, 0)),
+                v(4L, "1.0.4", "u4", LocalDateTime.of(2026, 2, 1, 0, 0))));
+        assertEquals("1.0.5", latest.version());
+    }
+
+    @Test
+    void test_task_163_normal_repeated_is_idempotent() {
+        List<WebVersion> rows = List.of(v(1L, "1.0.0", "u", LocalDateTime.of(2026, 1, 1, 0, 0)));
+        assertTrue(PublicVersionLookup.selectLatest(rows).equals(PublicVersionLookup.selectLatest(rows)));
+    }
+
+    @Test
+    void test_task_163_boundary_empty_input() {
+        assertNull(PublicVersionLookup.selectLatest(null));
+        assertNull(PublicVersionLookup.selectLatest(List.of()));
+    }
+
+    @Test
+    void test_task_163_boundary_single_item() {
+        WebVersion latest = PublicVersionLookup.selectLatest(
+                List.of(v(7L, "1.0.0", "u", LocalDateTime.of(2026, 1, 1, 0, 0))));
+        assertEquals("1.0.0", latest.version());
+    }
+
+    @Test
+    void test_task_163_boundary_limit_or_missing_field() {
+        Map<String, Object> empty = PublicVersionLookup.latestVersionResponse(null);
+        assertNull(empty.get("version"));
+        assertNull(empty.get("file_url"));
+    }
+
+    @Test
+    void test_task_163_invalid_input_rejected() {
+        Map<String, Object> resp = PublicVersionLookup.latestVersionResponse(
+                v(1L, "1.0.0", "https://x/f.zip", LocalDateTime.of(2026, 1, 1, 0, 0)));
+        assertFalse(resp.containsKey("success"), "无 ApiResponse 包装");
+        assertEquals("https://x/f.zip", resp.get("file_url"), "file_url 原样返回");
+    }
+
+    @Test
+    void test_task_163_dependency_failure_returns_actionable_message() {
+        assertTrue(PublicVersionLookup.isPublicVersionPath(PublicVersionLookup.PUBLIC_VERSION_PATH));
+        assertTrue(PublicVersionLookup.isPublicVersionPath(PublicVersionLookup.PUBLIC_VERSION_LATEST_PATH));
+        assertFalse(PublicVersionLookup.isPublicVersionPath(PublicVersionLookup.ADMIN_UPLOAD_PATH));
+    }
+}