wrong number of arguments error while testing comments controller using Rspec

While Testing Comments Controller, I get this error while creating a comment.

Failures:

  1) CommentsController Valid POST create creates a new comment
     Failure/Error: post :create, params: { comment: { content: 'TestCommentContent' }, topic_id: topic.id, post_id: post.id }

     ArgumentError:
       wrong number of arguments (given 2, expected 0)
     # ./spec/controllers/comments_controller_spec.rb:10:in `block (5 levels) in <top (required)>'
     # ./spec/controllers/comments_controller_spec.rb:9:in `block (4 levels) in <top (required)>'

Finished in 0.15835 seconds (files took 13.89 seconds to load)

This is my CommentsController rspec code:

require 'rails_helper'

RSpec.describe CommentsController, type: :controller do
  describe 'Valid' do
    let!(:topic) { Topic.create(title: 'test_Post_topic_title', name: 'test_Post_topic_name') }
    let!(:post) { Post.create(title: "TestPostTitle1", content: "TestPostContent1", topic_id: topic.id) }
    context 'POST create' do
      it 'creates a new comment' do
        expect do
          post :create, params: { comment: { content: 'TestCommentContent' }, topic_id: topic.id, post_id: post.id }
        end.to change(Comment, :count).by(1)
        expect(assigns(:comment).content).to eql "'TestCommentContent"
        expect(flash[:notice]).to match('Comment was successfully created.')
        expect(response).to redirect_to "/topics/#{assigns(:topic).id}/posts/#{assigns(:post).id}"
        expect(response).to have_http_status(:found) #302
      end
    end
end

In the development environment when I create a comment this is the log that has been created:

Started POST "/topics/3/posts/12/comments" for ::1 at 2021-05-13 14:01:49 +0530
Processing by CommentsController#create as HTML
  Parameters: {"authenticity_token"=>"[FILTERED]", "comment"=>{"content"=>"Yummy!!"}, "commit"=>"Create Comment", "topic_id"=>"3", "post_id"=>"12"}
  Topic Load (0.4ms)  SELECT "topics".* FROM "topics" WHERE "topics"."id" = ? LIMIT ?  [["id", 3], ["LIMIT", 1]]
  ↳ app/controllers/comments_controller.rb:59:in `get_topic_id'
  Post Load (0.5ms)  SELECT "posts".* FROM "posts" WHERE "posts"."id" = ? LIMIT ?  [["id", 12], ["LIMIT", 1]]
  ↳ app/controllers/comments_controller.rb:63:in `get_post_id'
  TRANSACTION (0.1ms)  begin transaction
  ↳ app/controllers/comments_controller.rb:8:in `create'
  Comment Create (112.8ms)  INSERT INTO "comments" ("post_id", "content", "created_at", "updated_at") VALUES (?, ?, ?, ?)  [["post_id", 12], ["content", "Yummy!!"], ["cr
eated_at", "2021-05-13 08:31:49.791154"], ["updated_at", "2021-05-13 08:31:49.791154"]]
  ↳ app/controllers/comments_controller.rb:8:in `create'
  TRANSACTION (1191.9ms)  commit transaction
  ↳ app/controllers/comments_controller.rb:8:in `create'
Redirected to http://localhost:3000/posts/12
Completed 302 Found in 1354ms (ActiveRecord: 1305.7ms | Allocations: 4639)

I have to send 3 parameters for this but it says that expected arguement is 0.?? how to resolve this. Thanks in Advance...!!!

You have defined post with let! which shadows the post method for sending request. Come up with another name for it.