create a post controller spec test

I am doing a controller test but it seems that spec.rb is wrong. Do you have a suggestion ?

This is my posts_controller.rb

class PostsController < ApplicationController

def create
    @post = Post.new(params[:post])
    if @post.save
      redirect_to @wall
    end
end

def destroy
    @post.destroy
end

end

and this is my posts_controller_spec.rb

require 'rails_helper'

describe PostsController do

  describe "#create" do
      it "saves the new post in the wall" do
      post :create, { wall_id: '1', content: "Some text I would like to put in my post" }

      end
  end

  describe "#destroy" do
    it "deletes the post in the wall" do

    end
  end
end

could you please help me to correct my spec.rb? Thanks