feat(*): 模型计费与渠道目录 - 支持视频 Token 报价结算和稳定模型展示

backend/internal/app/finance_token_arithmetic_test.go

@@ -0,0 +1,73 @@
+package app
+
+import (
+	"math"
+	"testing"
+
+	"infinite-canvas/backend/internal/model"
+)
+
+func TestTokenEstimateAmountUsesExactArithmetic(t *testing.T) {
+	for _, test := range []struct {
+		name       string
+		prices     model.ChannelModel
+		estimate   tokenBillingEstimate
+		multiplier int64
+		want       int64
+	}{
+		{
+			name: "video maximum price with multiplier",
+			prices: model.ChannelModel{
+				InputTokenPriceMicrocredits: 1_000_000_000_000, OutputTokenPriceMicrocredits: 1_000_000_000_000,
+			},
+			estimate: tokenBillingEstimate{OutputTokens: 10_000_000}, multiplier: 12_500, want: 12_500_000_000_000,
+		},
+		{
+			name: "text estimates input at full input price",
+			prices: model.ChannelModel{
+				InputTokenPriceMicrocredits: 2_000_000, OutputTokenPriceMicrocredits: 5_000_000, CachedTokenPriceMicrocredits: 1_000_000,
+			},
+			estimate: tokenBillingEstimate{InputTokens: 100, OutputTokens: 20}, multiplier: 10_000, want: 300,
+		},
+		{
+			name: "round after combining input and output",
+			prices: model.ChannelModel{
+				InputTokenPriceMicrocredits: 400_000, OutputTokenPriceMicrocredits: 400_000,
+			},
+			estimate: tokenBillingEstimate{InputTokens: 1, OutputTokens: 1}, multiplier: 12_500, want: 1,
+		},
+		{
+			name:     "maximum final amount",
+			prices:   model.ChannelModel{OutputTokenPriceMicrocredits: 1_000_000},
+			estimate: tokenBillingEstimate{OutputTokens: math.MaxInt64}, multiplier: 10_000, want: math.MaxInt64,
+		},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			amount, err := tokenEstimateAmount(&test.prices, test.estimate, test.multiplier)
+			if err != nil || amount != test.want {
+				t.Fatalf("tokenEstimateAmount() = %d, %v; want %d", amount, err, test.want)
+			}
+		})
+	}
+}
+
+func TestTokenEstimateAmountRejectsInvalidArithmetic(t *testing.T) {
+	for _, test := range []struct {
+		name       string
+		prices     model.ChannelModel
+		estimate   tokenBillingEstimate
+		multiplier int64
+	}{
+		{name: "negative input", estimate: tokenBillingEstimate{InputTokens: -1, OutputTokens: 1}, multiplier: 10_000},
+		{name: "negative output", estimate: tokenBillingEstimate{OutputTokens: -1}, multiplier: 10_000},
+		{name: "negative price", prices: model.ChannelModel{OutputTokenPriceMicrocredits: -1}, estimate: tokenBillingEstimate{OutputTokens: 1}, multiplier: 10_000},
+		{name: "zero multiplier", estimate: tokenBillingEstimate{OutputTokens: 1}},
+		{name: "final overflow", prices: model.ChannelModel{OutputTokenPriceMicrocredits: 1_000_000}, estimate: tokenBillingEstimate{OutputTokens: math.MaxInt64}, multiplier: 10_001},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			if amount, err := tokenEstimateAmount(&test.prices, test.estimate, test.multiplier); amount != 0 || err == nil {
+				t.Fatalf("invalid estimate billed %d, %v", amount, err)
+			}
+		})
+	}
+}