Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/handler/admin/usage_query_cache_test.go

@@ -0,0 +1,28 @@
+package admin
+
+import (
+	"testing"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/usagestats"
+	"github.com/stretchr/testify/require"
+)
+
+func TestUsageStatsCacheKey_StableAndDistinct(t *testing.T) {
+	start := time.Date(2026, 5, 29, 0, 0, 0, 0, time.UTC)
+	end := time.Date(2026, 5, 31, 0, 0, 0, 0, time.UTC)
+	base := usagestats.UsageLogFilters{StartTime: &start, EndTime: &end, Model: "claude-3"}
+
+	k1 := usageStatsCacheKey(base)
+	k2 := usageStatsCacheKey(base)
+	require.NotEmpty(t, k1)
+	require.Equal(t, k1, k2, "same filters must produce same key")
+
+	other := base
+	other.Model = "gpt-4o"
+	require.NotEqual(t, k1, usageStatsCacheKey(other), "different model must change key")
+
+	withUser := base
+	withUser.UserID = 7
+	require.NotEqual(t, k1, usageStatsCacheKey(withUser), "different user must change key")
+}