diff --git a/TESTING.md b/TESTING.md
index 669ff57..6626945 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -26,18 +26,26 @@ go test ./...
 
 ## 分阶段计划（长期）
 
-### 阶段 1（已落地/优先级最高）
+### 阶段 1（已落地）
 
 - provider 归一化：Vertex 默认 `google_location=global` 的回归保护
 - SyncService：Redis snapshot 写入与 routing key 生成
 - request_id：Gin middleware 透传/生成
 
-### 阶段 2（扩覆盖）
+### 阶段 2（已落地一部分）
 
-- Master/Key：token hash、epoch、scope、状态机分支
-- LogWriter：批处理/刷盘边界（可用 fake clock）
+- Master/Key：CreateMaster/ValidateMasterKey/IssueChildKey 的关键分支（含 child key 上限）
 
-### 阶段 3（契约测试）
+待补齐：
 
-- 与 DP 的 snapshot schema 契约：用 `testdata` golden 校验字段/格式稳定
+- Master/Key：epoch/禁用等更多状态分支
+- LogWriter：批处理/刷盘边界（可用 fake clock 或缩短 flush interval）
 
+### 阶段 3（已落地一部分：契约测试）
+
+- 与 DP 的 provider snapshot schema 契约：`internal/service/testdata/provider_snapshot.json` + SyncProvider 输出回归
+
+待扩展：
+
+- model snapshot 契约（能力字段、max_output_tokens 等）
+- token/master snapshot 契约（如果后续引入更多字段）
diff --git a/internal/service/master_test.go b/internal/service/master_test.go
new file mode 100644
index 0000000..5dcdc06
--- /dev/null
+++ b/internal/service/master_test.go
@@ -0,0 +1,69 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/ez-api/ez-api/internal/model"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+)
+
+func newTestDB(t *testing.T) *gorm.DB {
+	t.Helper()
+	db, err := gorm.Open(sqlite.Open("file::memory:?cache=shared"), &gorm.Config{})
+	if err != nil {
+		t.Fatalf("open sqlite: %v", err)
+	}
+	if err := db.AutoMigrate(&model.Master{}, &model.Key{}); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+	return db
+}
+
+func TestMasterService_CreateAndValidateMasterKey(t *testing.T) {
+	db := newTestDB(t)
+	svc := NewMasterService(db)
+
+	m, raw, err := svc.CreateMaster("m1", "default", 2, 10)
+	if err != nil {
+		t.Fatalf("CreateMaster: %v", err)
+	}
+	if raw == "" {
+		t.Fatalf("expected raw master key")
+	}
+	if m.MasterKeyDigest == "" {
+		t.Fatalf("expected master key digest to be set")
+	}
+
+	got, err := svc.ValidateMasterKey(raw)
+	if err != nil {
+		t.Fatalf("ValidateMasterKey: %v", err)
+	}
+	if got.ID != m.ID {
+		t.Fatalf("expected master id %d, got %d", m.ID, got.ID)
+	}
+}
+
+func TestMasterService_IssueChildKey_RespectsLimit(t *testing.T) {
+	db := newTestDB(t)
+	svc := NewMasterService(db)
+
+	m, _, err := svc.CreateMaster("m1", "default", 1, 10)
+	if err != nil {
+		t.Fatalf("CreateMaster: %v", err)
+	}
+
+	_, raw1, err := svc.IssueChildKey(m.ID, "default", "chat:write")
+	if err != nil {
+		t.Fatalf("IssueChildKey #1: %v", err)
+	}
+	if raw1 == "" {
+		t.Fatalf("expected raw child key")
+	}
+
+	_, _, err = svc.IssueChildKey(m.ID, "default", "chat:write")
+	if err == nil {
+		t.Fatalf("expected child key limit error")
+	}
+}
+
diff --git a/internal/service/sync_test.go b/internal/service/sync_test.go
index ed2b830..7ea5c00 100644
--- a/internal/service/sync_test.go
+++ b/internal/service/sync_test.go
@@ -2,6 +2,9 @@ package service
 
 import (
 	"encoding/json"
+	"os"
+	"path/filepath"
+	"reflect"
 	"testing"
 
 	"github.com/alicebob/miniredis/v2"
@@ -10,6 +13,16 @@ import (
 )
 
 func TestSyncProvider_WritesSnapshotAndRouting(t *testing.T) {
+	goldenPath := filepath.Join("testdata", "provider_snapshot.json")
+	goldenRaw, err := os.ReadFile(goldenPath)
+	if err != nil {
+		t.Fatalf("read golden %s: %v", goldenPath, err)
+	}
+	var golden map[string]any
+	if err := json.Unmarshal(goldenRaw, &golden); err != nil {
+		t.Fatalf("parse golden json: %v", err)
+	}
+
 	mr := miniredis.RunT(t)
 	rdb := redis.NewClient(&redis.Options{Addr: mr.Addr()})
 
@@ -40,8 +53,10 @@ func TestSyncProvider_WritesSnapshotAndRouting(t *testing.T) {
 	if err := json.Unmarshal([]byte(raw), &snap); err != nil {
 		t.Fatalf("invalid snapshot json: %v", err)
 	}
-	if snap["google_location"] != "global" {
-		t.Fatalf("expected google_location=global, got %v", snap["google_location"])
+	for k, v := range golden {
+		if !reflect.DeepEqual(snap[k], v) {
+			t.Fatalf("snapshot mismatch for %q: got=%#v want=%#v", k, snap[k], v)
+		}
 	}
 
 	routeKey := "route:group:default:gemini-3-pro-preview"
diff --git a/internal/service/testdata/provider_snapshot.json b/internal/service/testdata/provider_snapshot.json
new file mode 100644
index 0000000..08b3d0b
--- /dev/null
+++ b/internal/service/testdata/provider_snapshot.json
@@ -0,0 +1,13 @@
+{
+  "id": 42,
+  "name": "p1",
+  "type": "vertex-express",
+  "base_url": "",
+  "api_key": "",
+  "google_location": "global",
+  "group": "default",
+  "models": ["gemini-3-pro-preview"],
+  "status": "active",
+  "auto_ban": true
+}
+