如何在Rails中编写控制器测试

Question

I'm really not sure how to write a controller test.

Given is one of the controller action.

  class AccountsController < ApplicationController
    def pstn_rate_imports
        page = params[:page] || 1
        @pstn_rate_imports = @resporg_account_id.pstn_rate_imports.order('created_at desc').page(page).per(10)
        @pstn_rate_import = PstnRateImport.new
      end
   end

Now I approach this in 2 way..

1. I can insert data on PSTN Rate import table and then test that. and then write a test which probably will verify whether the returned object exactly matches to test result expectation.

Like,

get :pstn_rate_imports, id: 1, page: 1
expect(assigns(:pstn_rates_imports)).to eq(expected_result)

but here a problem, I would now need to sure of that I insert a correct data on DB (worry about validation etc, etc when creating records) Also, this does not adhere to the principle that any new chance you introduce should break your test.

2. OR I can mock the ActiveRecord call.

expect_any_instance_of(ResporgAccountId).to receive(:pstn_rate_imports) { some_arel }

expect(some_arel).to receive(:order).with('created_at desc') { some_arel }

expect(some_arel).to receive(:page).with('1') { some_arel }

expect(some_arel).to receive(:per).with(10) { some_arel }

get :pstn_rate_imports, id: 1, page: 1

This ensures that if I change anything the test would fail. But the problem is that I'm not sure how to mock the arel object or ActiveRecord method that returns an arel object .

So what is the correct way to write controller test in Rails.

Answer 1

The main principle is writing a test that covers the tested object functionality only.

So you need to:

• test the logic ( pstn_rate_imports method) creating a relative test for the model method
• test variables assigning and controller's specific logic (like .order ) in the controller. Model's methods (like pstn_rate_imports ) should be stubbed for sure. You can read more about the stubbing here .