code: func MockContext() sessionctx.Context {
  	ctx := mock.NewContext()
  	ctx.Store = &mock.Store{
  		Client: &mock.Client{},
  	}
  	ctx.GetSessionVars().CurrentDB = "test"
  	do := &domain.Domain{}
  	do.CreateStatsHandle(ctx)
  	domain.BindDomain(ctx, do)
  	return ctx
  }
docs: // MockContext is only used for plan related tests.