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

backend/internal/service/post_billing_platform_test.go

@@ -0,0 +1,81 @@
+//go:build unit
+
+package service
+
+import (
+	"context"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/ctxkey"
+)
+
+func TestPlatformFromAPIKey_NilSafe(t *testing.T) {
+	if got := PlatformFromAPIKey(nil); got != "" {
+		t.Errorf("nil APIKey should yield empty string, got %q", got)
+	}
+}
+
+func TestPlatformFromAPIKey_NilGroup(t *testing.T) {
+	k := &APIKey{Group: nil}
+	if got := PlatformFromAPIKey(k); got != "" {
+		t.Errorf("APIKey with nil Group should yield empty string, got %q", got)
+	}
+}
+
+func TestPlatformFromAPIKey_DerivesFromGroup(t *testing.T) {
+	tests := []struct {
+		name     string
+		platform string
+	}{
+		{"anthropic", "anthropic"},
+		{"openai", "openai"},
+		{"gemini", "gemini"},
+		{"antigravity", "antigravity"},
+		{"empty", ""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			k := &APIKey{
+				Group: &Group{Platform: tt.platform},
+			}
+			got := PlatformFromAPIKey(k)
+			if got != tt.platform {
+				t.Errorf("PlatformFromAPIKey(%q) = %q, want %q", tt.platform, got, tt.platform)
+			}
+		})
+	}
+}
+
+// TestQuotaPlatform 锁定配额计量口径：ForcePlatform 路由（如 /antigravity）按 ForcePlatform 计，
+// 否则回退到 Group 平台。preflight 与 post-billing 共用此口径，保证一致。
+func TestQuotaPlatform(t *testing.T) {
+	apiKey := &APIKey{Group: &Group{Platform: PlatformAnthropic}}
+
+	t.Run("no force platform falls back to group platform", func(t *testing.T) {
+		if got := QuotaPlatform(context.Background(), apiKey); got != PlatformAnthropic {
+			t.Errorf("QuotaPlatform without force = %q, want %q", got, PlatformAnthropic)
+		}
+	})
+
+	t.Run("force platform overrides group platform", func(t *testing.T) {
+		ctx := context.WithValue(context.Background(), ctxkey.ForcePlatform, PlatformAntigravity)
+		if got := QuotaPlatform(ctx, apiKey); got != PlatformAntigravity {
+			t.Errorf("QuotaPlatform with force = %q, want %q", got, PlatformAntigravity)
+		}
+	})
+
+	t.Run("empty force platform falls back to group platform", func(t *testing.T) {
+		ctx := context.WithValue(context.Background(), ctxkey.ForcePlatform, "")
+		if got := QuotaPlatform(ctx, apiKey); got != PlatformAnthropic {
+			t.Errorf("QuotaPlatform with empty force = %q, want %q", got, PlatformAnthropic)
+		}
+	})
+
+	t.Run("nil api key with force platform returns force platform", func(t *testing.T) {
+		ctx := context.WithValue(context.Background(), ctxkey.ForcePlatform, PlatformAntigravity)
+		if got := QuotaPlatform(ctx, nil); got != PlatformAntigravity {
+			t.Errorf("QuotaPlatform(nil) with force = %q, want %q", got, PlatformAntigravity)
+		}
+	})
+}