rails--rails/actionpack/test/controller/required_params_test.rb

require 'abstract_unit'

class BooksController < ActionController::Base
  def create
    params.require(:book).require(:name)
    head :ok
  end
end

class ActionControllerRequiredParamsTest < ActionController::TestCase
  tests BooksController

  test "missing required parameters will raise exception" do
    post :create, { magazine: { name: "Mjallo!" } }
    assert_response :bad_request

    post :create, { book: { title: "Mjallo!" } }
    assert_response :bad_request
  end

  test "required parameters that are present will not raise" do
    post :create, { book: { name: "Mjallo!" } }
    assert_response :ok
  end

  test "missing parameters will be mentioned in the return" do
    post :create, { magazine: { name: "Mjallo!" } }
    assert_equal "Required parameter missing: book", response.body
  end
end