test: 测试库改为模板克隆并纳入完整租号 e2e

每个包不再重复 DROP+迁移，清空改用 DELETE 并重置自增，go test ./... 从约 6 分钟降到十几秒。租号全链路改走 NewTestDB，去掉依赖额外 DSN 才会跑的过渡测试。

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/internal/database/testdb_test.go

@@ -0,0 +1,101 @@
+package database
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestAssertTestDatabaseName(t *testing.T) {
+	t.Parallel()
+	cases := []struct {
+		name    string
+		wantErr string
+	}{
+		{name: "hfb_sys_test", wantErr: ""},
+		{name: "hfb_sys_test_order", wantErr: ""},
+		{name: "hfb_e2e_flow", wantErr: ""},
+		{name: "", wantErr: "必须包含数据库名"},
+		{name: "hfb-sys-test", wantErr: "只允许字母、数字、下划线"},
+		{name: "hfb_sys", wantErr: "需包含 test 或 e2e"},
+		{name: strings.Repeat("test_", 20), wantErr: "超过 MySQL 上限"},
+	}
+	for _, item := range cases {
+		err := assertTestDatabaseName(item.name)
+		if item.wantErr == "" {
+			if err != nil {
+				t.Fatalf("%q: unexpected error %v", item.name, err)
+			}
+			continue
+		}
+		if err == nil || !strings.Contains(err.Error(), item.wantErr) {
+			t.Fatalf("%q: error = %v, want containing %q", item.name, err, item.wantErr)
+		}
+	}
+}
+
+func TestGooseUpSQL(t *testing.T) {
+	t.Parallel()
+	raw := "-- +goose Up\nCREATE TABLE t (id INT);\n-- +goose Down\nDROP TABLE t;\n"
+	got := strings.TrimSpace(gooseUpSQL(raw))
+	if got != "CREATE TABLE t (id INT);" {
+		t.Fatalf("gooseUpSQL = %q", got)
+	}
+}
+
+func TestNewDryRunDB(t *testing.T) {
+	t.Parallel()
+	if NewDryRunDB() == nil {
+		t.Fatal("NewDryRunDB returned nil")
+	}
+}
+
+func TestNewTestDBTruncatesBetweenCalls(t *testing.T) {
+	db := NewTestDB()
+	if err := db.Exec("INSERT INTO users (phone) VALUES ('13900001111')").Error; err != nil {
+		t.Fatalf("insert user: %v", err)
+	}
+	var n int64
+	if err := db.Raw("SELECT COUNT(*) FROM users").Scan(&n).Error; err != nil {
+		t.Fatal(err)
+	}
+	if n != 1 {
+		t.Fatalf("users count = %d, want 1", n)
+	}
+
+	db = NewTestDB()
+	if err := db.Raw("SELECT COUNT(*) FROM users").Scan(&n).Error; err != nil {
+		t.Fatal(err)
+	}
+	if n != 0 {
+		t.Fatalf("users count after reset = %d, want 0", n)
+	}
+}
+
+func TestNewTestDBKeepsSchemaFingerprint(t *testing.T) {
+	db := NewTestDB()
+	var fingerprint string
+	if err := db.Raw("SELECT v FROM " + schemaMetaTable + " WHERE k = 'fingerprint'").Scan(&fingerprint).Error; err != nil {
+		t.Fatalf("read fingerprint: %v", err)
+	}
+	if fingerprint == "" {
+		t.Fatal("expected schema fingerprint to survive truncate")
+	}
+}
+
+func TestNewTestDBResetsAutoIncrement(t *testing.T) {
+	db := NewTestDB()
+	if err := db.Exec("INSERT INTO users (phone) VALUES ('13900002222')").Error; err != nil {
+		t.Fatal(err)
+	}
+	db = NewTestDB()
+	if err := db.Exec("INSERT INTO users (phone) VALUES ('13900003333')").Error; err != nil {
+		t.Fatal(err)
+	}
+	var id uint64
+	if err := db.Raw("SELECT id FROM users WHERE phone = '13900003333'").Scan(&id).Error; err != nil {
+		t.Fatal(err)
+	}
+	if id != 1 {
+		t.Fatalf("id after reset = %d, want 1", id)
+	}
+}