feat(Trends): AI 趋势解读上线 — 数据指纹缓存,秒开不重算

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

康康Tests/TrendInsightCacheTests.swift

@@ -0,0 +1,43 @@
+import Testing
+import SwiftUI
+@testable import 康康
+
+@MainActor
+struct TrendInsightCacheTests {
+
+    private func bucket(values: [Double]) -> SeriesBucket {
+        let points = values.enumerated().map { i, v in
+            SeriesBucket.Point(id: "p\(i)",
+                               date: Date(timeIntervalSince1970: Double(i) * 86_400),
+                               value: v, status: .normal)
+        }
+        let line = SeriesBucket.SeriesLine(id: "glucose.fasting", seriesKey: "glucose.fasting",
+                                           label: nil, color: .blue, points: points,
+                                           referenceRange: 3.9...6.1)
+        return SeriesBucket(id: "glucose.fasting", title: "空腹血糖", unit: "mmol/L",
+                            lines: [line], latestDate: .now, kind: .monitor)
+    }
+
+    @Test func fingerprintStableForSameData() {
+        let a = TrendInsightService.fingerprint(for: bucket(values: [5.2, 5.5]))
+        let b = TrendInsightService.fingerprint(for: bucket(values: [5.2, 5.5]))
+        #expect(a == b)
+    }
+
+    @Test func fingerprintChangesWhenDataChanges() {
+        let a = TrendInsightService.fingerprint(for: bucket(values: [5.2, 5.5]))
+        let b = TrendInsightService.fingerprint(for: bucket(values: [5.2, 5.5, 6.0]))
+        #expect(a != b)
+    }
+
+    @Test func dataLinesFormatsDateAndValue() {
+        let lines = TrendInsightService.dataLines(for: bucket(values: [5.2, 5.5]))
+        #expect(lines.contains("1970-01-01 5.2"))
+        #expect(lines.contains("1970-01-02 5.5"))
+    }
+
+    @Test func rangeTextRendersReference() {
+        #expect(TrendInsightService.rangeText(for: bucket(values: [5.2]))
+                == ",参考 3.9-6.1")
+    }
+}