discourse/plugins/chat/spec/lib/steps_inspector_spec.rb
Martin Brennan 60ad836313
DEV: Chat service object initial implementation (#19814)
This is a combined work of Martin Brennan, Loïc Guitaut, and Joffrey Jaffeux.

---

This commit implements a base service object when working in chat. The documentation is available at https://discourse.github.io/discourse/chat/backend/Chat/Service.html

Generating documentation has been made as part of this commit with a bigger goal in mind of generally making it easier to dive into the chat project.

Working with services generally involves 3 parts:

- The service object itself, which is a series of steps where few of them are specialized (model, transaction, policy)

```ruby
class UpdateAge
  include Chat::Service::Base

  model :user, :fetch_user
  policy :can_see_user
  contract
  step :update_age

  class Contract
    attribute :age, :integer
  end

  def fetch_user(user_id:, **)
    User.find_by(id: user_id)
  end

  def can_see_user(guardian:, **)
    guardian.can_see_user(user)
  end

  def update_age(age:, **)
    user.update!(age: age)
  end
end
```

- The `with_service` controller helper, handling success and failure of the service within a service and making easy to return proper response to it from the controller

```ruby
def update
  with_service(UpdateAge) do
    on_success { render_serialized(result.user, BasicUserSerializer, root: "user") }
  end
end
```

- Rspec matchers and steps inspector, improving the dev experience while creating specs for a service

```ruby
RSpec.describe(UpdateAge) do
  subject(:result) do
    described_class.call(guardian: guardian, user_id: user.id, age: age)
  end

  fab!(:user) { Fabricate(:user) }
  fab!(:current_user) { Fabricate(:admin) }

  let(:guardian) { Guardian.new(current_user) }
  let(:age) { 1 }

   it { expect(user.reload.age).to eq(age) }
end
```

Note in case of unexpected failure in your spec, the output will give all the relevant information:

```
  1) UpdateAge when no channel_id is given is expected to fail to find a model named 'user'
     Failure/Error: it { is_expected.to fail_to_find_a_model(:user) }

       Expected model 'foo' (key: 'result.model.user') was not found in the result object.

       [1/4] [model] 'user' 
       [2/4] [policy] 'can_see_user'
       [3/4] [contract] 'default'
       [4/4] [step] 'update_age'

       /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/update_age.rb:32:in `fetch_user': missing keyword: :user_id (ArgumentError)
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:202:in `instance_exec'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:202:in `call'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:219:in `call'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:417:in `block in run!'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:417:in `each'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:417:in `run!'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:411:in `run'
       	from <internal:kernel>:90:in `tap'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:302:in `call'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/spec/services/update_age_spec.rb:15:in `block (3 levels) in <main>'
```
2023-02-13 13:09:57 +01:00

176 lines
4.3 KiB
Ruby

# frozen_string_literal: true
RSpec.describe Chat::StepsInspector do
class DummyService
include Chat::Service::Base
model :model
policy :policy
contract
transaction do
step :in_transaction_step_1
step :in_transaction_step_2
end
step :final_step
class Contract
attribute :parameter
validates :parameter, presence: true
end
end
subject(:inspector) { described_class.new(result) }
let(:parameter) { "present" }
let(:result) { DummyService.call(parameter: parameter) }
before do
class DummyService
%i[fetch_model policy in_transaction_step_1 in_transaction_step_2 final_step].each do |name|
define_method(name) { true }
end
end
end
describe "#inspect" do
subject(:output) { inspector.inspect }
context "when service runs without error" do
it "outputs all the steps of the service" do
expect(output).to eq <<~OUTPUT.chomp
[1/7] [model] 'model'
[2/7] [policy] 'policy'
[3/7] [contract] 'default'
[4/7] [transaction]
[5/7] [step] 'in_transaction_step_1'
[6/7] [step] 'in_transaction_step_2'
[7/7] [step] 'final_step'
OUTPUT
end
end
context "when the model step is failing" do
before do
class DummyService
def fetch_model
false
end
end
end
it "shows the failing step" do
expect(output).to eq <<~OUTPUT.chomp
[1/7] [model] 'model'
[2/7] [policy] 'policy'
[3/7] [contract] 'default'
[4/7] [transaction]
[5/7] [step] 'in_transaction_step_1'
[6/7] [step] 'in_transaction_step_2'
[7/7] [step] 'final_step'
OUTPUT
end
end
context "when the policy step is failing" do
before do
class DummyService
def policy
false
end
end
end
it "shows the failing step" do
expect(output).to eq <<~OUTPUT.chomp
[1/7] [model] 'model'
[2/7] [policy] 'policy'
[3/7] [contract] 'default'
[4/7] [transaction]
[5/7] [step] 'in_transaction_step_1'
[6/7] [step] 'in_transaction_step_2'
[7/7] [step] 'final_step'
OUTPUT
end
end
context "when the contract step is failing" do
let(:parameter) { nil }
it "shows the failing step" do
expect(output).to eq <<~OUTPUT.chomp
[1/7] [model] 'model'
[2/7] [policy] 'policy'
[3/7] [contract] 'default'
[4/7] [transaction]
[5/7] [step] 'in_transaction_step_1'
[6/7] [step] 'in_transaction_step_2'
[7/7] [step] 'final_step'
OUTPUT
end
end
context "when a common step is failing" do
before do
class DummyService
def in_transaction_step_2
fail!("step error")
end
end
end
it "shows the failing step" do
expect(output).to eq <<~OUTPUT.chomp
[1/7] [model] 'model'
[2/7] [policy] 'policy'
[3/7] [contract] 'default'
[4/7] [transaction]
[5/7] [step] 'in_transaction_step_1'
[6/7] [step] 'in_transaction_step_2'
[7/7] [step] 'final_step'
OUTPUT
end
end
end
describe "#error" do
subject(:error) { inspector.error }
context "when there are no errors" do
it "returns nothing" do
expect(error).to be_blank
end
end
context "when the model step is failing" do
before do
class DummyService
def fetch_model
false
end
end
end
it "returns an error related to the model" do
expect(error).to match(/Model not found/)
end
end
context "when the contract step is failing" do
let(:parameter) { nil }
it "returns an error related to the contract" do
expect(error).to match(/ActiveModel::Error attribute=parameter, type=blank, options={}/)
end
end
context "when a common step is failing" do
before { result["result.step.final_step"].fail(error: "my error") }
it "returns an error related to the step" do
expect(error).to eq("my error")
end
end
end
end