diff --git a/backend-java/src/test/java/com/nanri/aiimage/modules/similarasin/service/support/FilePhaseSemanticsTest.java b/backend-java/src/test/java/com/nanri/aiimage/modules/similarasin/service/support/FilePhaseSemanticsTest.java
new file mode 100644
index 00000000..cca15ec6
--- /dev/null
+++ b/backend-java/src/test/java/com/nanri/aiimage/modules/similarasin/service/support/FilePhaseSemanticsTest.java
@@ -0,0 +1,168 @@
+package com.nanri.aiimage.modules.similarasin.service.support;
+
+import com.baomidou.mybatisplus.core.MybatisConfiguration;
+import com.baomidou.mybatisplus.core.metadata.TableInfoHelper;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.nanri.aiimage.modules.file.service.oss.OssStorageService;
+import com.nanri.aiimage.modules.similarasin.model.vo.SimilarAsinHistoryItemVo;
+import com.nanri.aiimage.modules.task.mapper.FileTaskMapper;
+import com.nanri.aiimage.modules.task.mapper.TaskChunkMapper;
+import com.nanri.aiimage.modules.task.mapper.TaskScopeStateMapper;
+import com.nanri.aiimage.modules.task.model.entity.FileResultEntity;
+import com.nanri.aiimage.modules.task.model.entity.FileTaskEntity;
+import com.nanri.aiimage.modules.task.model.entity.TaskFileJobEntity;
+import com.nanri.aiimage.modules.task.model.entity.TaskScopeStateEntity;
+import com.nanri.aiimage.modules.task.service.TaskProgressSnapshotService;
+import com.nanri.aiimage.modules.task.service.TransientPayloadStorageService;
+import org.apache.ibatis.builder.MapperBuilderAssistant;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.lenient;
+import static org.mockito.Mockito.when;
+
+/**
+ * task-142：fileReady/fileStatus 语义契约（plan 08）。
+ * fileReady = resultFileUrl 非空；无 job 时 fileStatus = ready?SUCCESS:null；
+ * 有 job 时 fileStatus = job.status；fileError = job.errorMessage。
+ */
+@ExtendWith(MockitoExtension.class)
+class FilePhaseSemanticsTest {
+
+    private static final Long TASK_ID = 1212L;
+    private static final Long RESULT_ID = 1213L;
+
+    @Mock private TaskScopeStateMapper taskScopeStateMapper;
+    @Mock private TaskChunkMapper taskChunkMapper;
+    @Mock private FileTaskMapper fileTaskMapper;
+    @Mock private TaskProgressSnapshotService taskProgressSnapshotService;
+    @Mock private OssStorageService ossStorageService;
+    @Mock private TransientPayloadStorageService transientPayloadStorageService;
+    @Mock private ObjectMapper objectMapper;
+
+    private SimilarAsinHistoryAssembler assembler;
+
+    @BeforeAll
+    static void initializeMybatisMetadata() {
+        MapperBuilderAssistant assistant = new MapperBuilderAssistant(new MybatisConfiguration(), "");
+        TableInfoHelper.initTableInfo(assistant, FileResultEntity.class);
+        TableInfoHelper.initTableInfo(assistant, TaskScopeStateEntity.class);
+    }
+
+    @BeforeEach
+    void setUp() {
+        assembler = new SimilarAsinHistoryAssembler(taskScopeStateMapper, taskChunkMapper, fileTaskMapper,
+                taskProgressSnapshotService, ossStorageService, transientPayloadStorageService, objectMapper);
+        lenient().when(taskScopeStateMapper.selectCount(any())).thenReturn(0L);
+        lenient().when(taskScopeStateMapper.selectList(any())).thenReturn(List.of());
+        lenient().when(taskProgressSnapshotService.find(any(), any())).thenReturn(null);
+        lenient().when(taskChunkMapper.selectCount(any())).thenReturn(0L);
+        lenient().when(ossStorageService.generateFreshDownloadUrl(any())).thenReturn("https://dl.example/x.xlsx");
+    }
+
+    private SimilarAsinHistoryItemVo build(FileResultEntity row, TaskFileJobEntity job) {
+        FileTaskEntity task = new FileTaskEntity();
+        task.setId(TASK_ID);
+        task.setModuleType("SIMILAR_ASIN");
+        task.setStatus("RUNNING");
+        return assembler.buildHistoryItems(List.of(row), Map.of(TASK_ID, task),
+                job == null ? Map.of() : Map.of(RESULT_ID, job)).getFirst();
+    }
+
+    private FileResultEntity row(String url) {
+        FileResultEntity row = new FileResultEntity();
+        row.setId(RESULT_ID);
+        row.setTaskId(TASK_ID);
+        row.setSourceFilename("source.xlsx");
+        row.setResultFileUrl(url);
+        row.setSuccess(0);
+        return row;
+    }
+
+    private TaskFileJobEntity job(String status, String error) {
+        TaskFileJobEntity job = new TaskFileJobEntity();
+        job.setId(901L);
+        job.setTaskId(TASK_ID);
+        job.setResultId(RESULT_ID);
+        job.setStatus(status);
+        job.setErrorMessage(error);
+        return job;
+    }
+
+    @Test
+    void readyTrueWhenUrlPresent() {
+        SimilarAsinHistoryItemVo vo = build(row("oss://result/a.xlsx"), null);
+
+        assertEquals(Boolean.TRUE, vo.getFileReady());
+    }
+
+    @Test
+    void readyFalseWhenUrlBlank() {
+        SimilarAsinHistoryItemVo vo = build(row(null), null);
+
+        assertFalse(Boolean.TRUE.equals(vo.getFileReady()));
+    }
+
+    @Test
+    void noJobWithReadyMapsToSuccessStatus() {
+        SimilarAsinHistoryItemVo vo = build(row("oss://result/a.xlsx"), null);
+
+        assertEquals("SUCCESS", vo.getFileStatus(), "无 job 且 ready 时 fileStatus=SUCCESS");
+    }
+
+    @Test
+    void noJobWithoutReadyMapsToNullStatus() {
+        SimilarAsinHistoryItemVo vo = build(row(null), null);
+
+        assertNull(vo.getFileStatus(), "无 job 且未 ready 时 fileStatus=null");
+        assertNull(vo.getFileJobId());
+    }
+
+    @Test
+    void jobStatusMappedDirectly() {
+        SimilarAsinHistoryItemVo vo = build(row("oss://result/a.xlsx"), job("RUNNING", null));
+
+        assertEquals("RUNNING", vo.getFileStatus(), "有 job 时 fileStatus=job.status");
+        assertEquals(901L, vo.getFileJobId());
+    }
+
+    @Test
+    void jobErrorMappedDirectly() {
+        SimilarAsinHistoryItemVo vo = build(row(null), job("FAILED", "组装失败: 超时"));
+
+        assertEquals("组装失败: 超时", vo.getFileError(), "fileError=job.errorMessage");
+        assertEquals("FAILED", vo.getFileStatus());
+    }
+
+    @Test
+    void blankWhitespaceUrlIsNotReady() {
+        SimilarAsinHistoryItemVo vo = build(row("   "), null);
+
+        assertFalse(Boolean.TRUE.equals(vo.getFileReady()), "空白字符串不算 ready");
+        assertNull(vo.getFileStatus());
+    }
+
+    @Test
+    void semanticsFrozenCombined() {
+        // 组合快照：URL + SUCCESS job → ready=true、status=SUCCESS、error 映射、jobId 携带
+        SimilarAsinHistoryItemVo vo = build(row("oss://result/a.xlsx"), job("SUCCESS", null));
+
+        assertEquals(Boolean.TRUE, vo.getFileReady());
+        assertEquals("SUCCESS", vo.getFileStatus());
+        assertNull(vo.getFileError());
+        assertEquals(901L, vo.getFileJobId());
+        assertTrue(vo.getFileReady());
+    }
+}