test(ai): erp-ai 从零增至 34 个单元测试 — 覆盖 DTO/error/prompt/sanitization

- dto.rs: 8 个测试（AnalysisType 映射、serde round-trip、SSE 事件、默认值）
- error.rs: 10 个测试（AiError 全部 10 个变体 → AppError 映射）
- prompt: 8 个测试（变量替换、嵌套对象、数组迭代、条件、严格模式缺失变量）
- sanitization: 8 个测试（4 种 DTO 脱敏通过、PII 字段检测、空数据边界）

crates/erp-ai/src/dto.rs

@@ -100,3 +100,118 @@ pub enum AnalysisSseEvent {
     #[serde(rename = "error")]
     Error { message: String },
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // ---- AnalysisType::as_str ----
+
+    #[test]
+    fn analysis_type_as_str() {
+        assert_eq!(AnalysisType::LabReport.as_str(), "lab_report");
+        assert_eq!(AnalysisType::Trends.as_str(), "trend");
+        assert_eq!(AnalysisType::CheckupPlan.as_str(), "checkup_plan");
+        assert_eq!(AnalysisType::ReportSummary.as_str(), "report_summary");
+    }
+
+    // ---- AnalysisType::prompt_name ----
+
+    #[test]
+    fn analysis_type_prompt_name() {
+        assert_eq!(AnalysisType::LabReport.prompt_name(), "lab_report_interpretation");
+        assert_eq!(AnalysisType::Trends.prompt_name(), "health_trend_analysis");
+        assert_eq!(AnalysisType::CheckupPlan.prompt_name(), "personalized_checkup_plan");
+        assert_eq!(AnalysisType::ReportSummary.prompt_name(), "report_summary_generation");
+    }
+
+    // ---- AnalysisType serde round-trip ----
+
+    #[test]
+    fn analysis_type_serde_roundtrip() {
+        let types = vec![
+            AnalysisType::LabReport,
+            AnalysisType::Trends,
+            AnalysisType::CheckupPlan,
+            AnalysisType::ReportSummary,
+        ];
+        for t in types {
+            let json = serde_json::to_string(&t).unwrap();
+            let back: AnalysisType = serde_json::from_str(&json).unwrap();
+            assert_eq!(t, back);
+        }
+    }
+
+    #[test]
+    fn analysis_type_deserialize_snake_case() {
+        let t: AnalysisType = serde_json::from_str("\"lab_report\"").unwrap();
+        assert_eq!(t, AnalysisType::LabReport);
+
+        let t: AnalysisType = serde_json::from_str("\"trends\"").unwrap();
+        assert_eq!(t, AnalysisType::Trends);
+    }
+
+    // ---- AnalyzeOptions::default ----
+
+    #[test]
+    fn analyze_options_default() {
+        let opts = AnalyzeOptions::default();
+        assert_eq!(opts.detail_level, Some("patient_friendly".to_string()));
+        assert_eq!(opts.language, Some("zh-CN".to_string()));
+    }
+
+    // ---- AnalysisSseEvent serde round-trip ----
+
+    #[test]
+    fn sse_event_chunk_roundtrip() {
+        let event = AnalysisSseEvent::Chunk {
+            content: "血红蛋白偏低".to_string(),
+            index: 0,
+        };
+        let json = serde_json::to_string(&event).unwrap();
+        assert!(json.contains("\"type\":\"chunk\""));
+        let back: AnalysisSseEvent = serde_json::from_str(&json).unwrap();
+        match back {
+            AnalysisSseEvent::Chunk { content, index } => {
+                assert_eq!(content, "血红蛋白偏低");
+                assert_eq!(index, 0);
+            }
+            _ => panic!("期望 Chunk 变体"),
+        }
+    }
+
+    #[test]
+    fn sse_event_done_roundtrip() {
+        let id = {
+            let ts = uuid::Timestamp::now(uuid::NoContext);
+            uuid::Uuid::new_v7(ts)
+        };
+        let event = AnalysisSseEvent::Done {
+            analysis_id: id,
+            status: "completed".to_string(),
+        };
+        let json = serde_json::to_string(&event).unwrap();
+        let back: AnalysisSseEvent = serde_json::from_str(&json).unwrap();
+        match back {
+            AnalysisSseEvent::Done { analysis_id, status } => {
+                assert_eq!(analysis_id, id);
+                assert_eq!(status, "completed");
+            }
+            _ => panic!("期望 Done 变体"),
+        }
+    }
+
+    #[test]
+    fn sse_event_error_roundtrip() {
+        let event = AnalysisSseEvent::Error {
+            message: "超时".to_string(),
+        };
+        let json = serde_json::to_string(&event).unwrap();
+        assert!(json.contains("\"type\":\"error\""));
+        let back: AnalysisSseEvent = serde_json::from_str(&json).unwrap();
+        match back {
+            AnalysisSseEvent::Error { message } => assert_eq!(message, "超时"),
+            _ => panic!("期望 Error 变体"),
+        }
+    }
+}