Rspec test fails while rendering

For my user controller, while running the test cases I am facing render issue. It is redirecting to http://test.host/sign_in instead of rendering new.

1. Controller code

         def create
        @user = User.new(user_params)
        respond_to do |format|
            if @user.save
                
                UserMailer.registration_confirmation(@user).deliver_now
                session[:user_id] = @user.id
                
                    format.html { redirect_to sign_in_path, notice: 'User was successfully created.' }
                    format.json { render :show, status: :created, location: @user }
                
            else
            
                format.html { render :new }
                format.json { render json: @user.errors, status: :unprocessable_entity }
            
            end
        end
    end

2. spec/users_controller_spec.rb

         describe '#create' do
            it 'User created' do
              new_user = FactoryBot.build :user
              post :create, params: {
                user: {
                  id: new_user.id,
                  firstname: new_user.firstname,
                  email: new_user.email,
                  password: "s",
                  password_confirmation:"s"

                }
              }
              expect(response).to render_template("new")
             
            end
        end

While running this test case I am facing this error!

3. Error

        Failures:

  1) UsersController  controller test cases  #create User created
     Failure/Error: expect(response).to render_template("new")
       expecting <"new"> but was a redirect to <http://test.host/sign_in>
     # ./spec/controllers/users_controller_spec.rb:30:in `block (4 levels) in <top (required)>'

How do I resolve this?