Rspec: Test an exception which is not handled - ruby-on-rails

In my public method #recalculate, calling the private method1. This method throw exception 'StandardError'. I want to test this scenario, however getting an error.
Note: I don't want to handle an exception.
def recalculate
method_1
end
private
def method_1
## do some calculation
raise StandardError.new("Test")
end
Rspec Test case:
it "Test" do
expect { #product.recalculate.recalculate }.to raise_error(StandardError)
#product.recalculate
end
1) Product.Test
Failure/Error: #product.recalculate
StandardError:
Test
(required)>'
Finished in 1.39 seconds
1 example, 1 failure

According to your example, the second line #product.recalculate raises an actual exception hence the error. Assuming recalculate method is defined in #product object, this should be enough to test it.
it "Test" do
expect { #product.recalculate }.to raise_error(StandardError)
end

Related

How to Raise Runtime Error in Rspec-Rails

I have to test a code where I am raising some errors, I tried several techniques but it failed. The structure of the class is defined below:
SchemaController:
class SchemasController < ApplicationController
def index
#get_schema = Api::AnalyticsQueryBuilderMetadataService::Schema.show
end
end
Show method under Api -> AnalyticsQueryBuilderMetadataService -> Schema.rb file:
def self.show
params = { 'limit' => 40 }
response = Api::Connection.initiate_request('entities', params)
if response.nil?
Rails.logger.error 'Data not found for ClientId '
raise 'Data not found'
else
get_schema(response)
end
end
Rspec test I wrote for schema_spec.rb:
require 'rails_helper'
require 'spec_helper'
RSpec.describe Api::AnalyticsQueryBuilderMetadataService::Schema do
describe 'GET all schema' do
before do
# allow_any_instance_of(SchemasController).to receive(:connection).and_return({})
#binding.pry
allow(Api::Connection).to receive(:initiate_request).and_return(nil)
end
context 'When no json body is passed' do
it 'Raises NoMethodError' do
# obj = SchemasController.new
result = Api::AnalyticsQueryBuilderMetadataService::Schema.show()
# expect {result}.to raise_error(RuntimeError)
expect{result}.to raise_error
end
end
end
end
But It is giving error as:
Failures:
1) Api::AnalyticsQueryBuilderMetadataService::Schema GET all schema When no json body is passed Raises NoMethodError
Failure/Error: raise 'Data not found'
RuntimeError:
Data not found
# ./app/lib/api/analytics_query_builder_metadata_service/schema.rb:22:in `show'
# ./spec/lib/api/analytics_query_builder_metadata_service/schema_spec.rb:17:in `block (4 levels) in <top (required)>'
Finished in 2.3 seconds (files took 5.63 seconds to load)
44 examples, 1 failure
Failed examples:
rspec ./spec/lib/api/analytics_query_builder_metadata_service/schema_spec.rb:15 # Api::AnalyticsQueryBuilderMetadataService::Schema GET all schema When no json body is passed Raises NoMethodError
Help me to solve this.
From the docs;
Use the raise_error matcher to specify that a block of code raises an
error.
It means that the code in the block should be the one raising the error, but in your case the error is being raised when you declare the result variable.
To make it work you can skip the variable declaration and pass the variable value as the expect block;
expect { Api::AnalyticsQueryBuilderMetadataService::Schema.show }
.to raise_error(StandardError, 'Data not found')

RSpec + Sidekiq: NoMethodError: undefined method 'jobs' MyImportJob

I am trying to write some specs for RSpec + Sidekiq in a Rails 4.2.4 app, but am encountering some issues.
My code looks like this:
class MyImportJob
include Sidekiq::Worker
sidekiq_options queue: :default
def perform(params)
# Do magic
end
end
and the spec:
describe MyImportJob, type: :job do
let(:panel) { create(:panel) }
describe '#perform' do
context 'unsuccessfully' do
it 'raises ArgumentError if no panel param was passed' do
expect {subject.perform_async()}.to raise_error(ArgumentError)
end
end
context 'successfully' do
it 'given a panel, it increases the job number' do
expect {
subject.perform_async(panel_id: panel.id)
}.to change(subject.jobs, :size).by(1)
end
end
end
end
But I am receiving the following errors:
Failure/Error: }.to change(subject.jobs, :size).by(1)
NoMethodError:
undefined method `jobs' for #<MyImportJob:0x007f80b74c5c18>
and
Failure/Error: expect {subject.perform_async()}.to raise_error(ArgumentError)
expected ArgumentError, got #<NoMethodError: undefined method `perform_async' for #<MyImportJob:0x007f80b6d73f50>>
I believe perform_async should be provided by default by Sidekiq as long as I include the line include Sidekiq::Worker in my worker, is this correct? The first test passes if I just use perform but I'd expect it to pass with perform_async which is what I'm using in my codebase.
As for the second, I don't understand why there is no method jobs for the test subject. Any clue about that?
My rails_helper.rb file has:
require 'sidekiq/testing'
Sidekiq::Testing.fake!
Thanks in advance!
In case you don't define subject explicitly, rspec will create subject as following rule:
By default, if the first argument to an outermost example group
(describe or context block) is a class, RSpec creates an instance of
that class and assigns it to the subject
ref: What's the difference between RSpec's subject and let? When should they be used or not?
That means it create instance of your worker. So that you can't call perform_async and jobs.
To resolve your issue, define it explicitly as below:
describe MyImportJob, type: :job do
let(:panel) { create(:panel) }
subject { MyImportJob }
describe '#perform' do
context 'unsuccessfully' do
it 'raises ArgumentError if no panel param was passed' do
expect {subject.perform_async()}.to raise_error(ArgumentError)
end
end
context 'successfully' do
it 'given a panel, it increases the job number' do
expect {
subject.perform_async(panel_id: panel.id)
}.to change(subject.jobs, :size).by(1)
end
end
end
end
expected ArgumentError, got #<NoMethodError: undefined method 'perform_async' for #<MyImportJob:0x007f80b6d73f50>>
perform_async is a method on worker class itself.
MyImportJob.perform_async(...)
I don't understand why there is no method jobs for the test subject
The same exact reason. It's a method on the worker class.

How to test that a method is called using rspec?

In a model spec, I want to test that certain methods are being called correctly.
#models/object.rb
class Object < ActiveRecord::Base
after_validation :do_this
after_save :enqueue_that
def do_this
# does some stuff, the results of which I don't want to test
end
def enqueue_that
MyWorker.perform_later id
end
end
#spec/models/object.rb
describe Object
describe '#do_this' do
it 'is called on save with passing validations' do
object.save
expect(object).to receive(:do_this)
end
end
describe '#enqueue_that' do
it 'is called after save' do
object.save
expect(MyWorker).to receive(:perform_later).once
end
end
end
The tests are failing with the following
Failure/Error: expect(object).to receive(:do_this).once
(#<Object:0x007fd2101c7160>).do_this(*(any args))
expected: 1 time with any arguments
received: 0 times with any arguments
Failure/Error: expect(MyWorker).to receive(:perform_later).once
(MyWorker (class)).perform_later(*(any args))
expected: 1 time with any arguments
received: 0 times with any arguments
Confusingly, these methods appear to be behaving correctly in the dev environment.
Am I using expect().to receive correctly? Or have my tests uncovered a genuine bug?
You just have things in the wrong order...
it 'is called on save with passing validations' do
expect(object).to receive(:do_this)
object.save
end

rspec: how to test the ensure block after raised an error

Here's my begin..rescue..ensure block. I want to write some test cases that after error is raised, the final result {} will be returned.
I am using rspec 3.3.
def external_call
result = ExternalApi.call
rescue => e
# handle the error, and re-raise
Handler.handle(e)
raise
ensure
result.presence || {}
end
I have wrote test case for the rescue part:
context 'when external api raise error' do
it 'handles the error, and re-raise' do
allow(ExternalApi).to receive(:call).and_raise(SomeError)
expect(Handler).to receive(:handle).with(e)
expect { subject.external_call }.to raise_error(SomeError)
end
end
But I am not sure how to test the ensure part after the error is re-raised.
Here's my attempt:
it 'returns {} after error raised' do
allow(ExternalApi).to receive(:call).and_raise(SomeError)
result = subject.external_call
expect(result).to eq({})
end
In this case, the test case will fail in the subject.external_call line, since it will raise error there. I am not sure how to test this cases after the error is re-raised.
When using begin/rescue/ensure block with implicit returns, ruby will return the last method to be run in the rescue block as the return value, not the ensure. If the value from the ensure block needs to be returned, it will either have to be explicitly returned, or not included in an ensure but instead moved outside of the begin/rescue block.
Below is an example which shows the difference.
class TestClass
def self.method1
raise 'an error'
rescue
'rescue block'
ensure
'ensure block'
end
def self.method2
raise 'an error'
rescue
'rescue block'
ensure
return 'ensure block'
end
def self.method3
begin
raise 'an error'
rescue
'rescue block'
end
'ensure equivalent block'
end
end
RSpec.describe TestClass do
it do
# does not work, method1 returns 'rescue block'
expect(TestClass.method1).to eql 'ensure block'
end
it do
# does work, as method2 explicitly returns 'ensure block'
expect(TestClass.method2).to eql 'ensure block'
end
it do
# does work, as method3 uses 'ensure equivalent block' as the inferred return
expect(TestClass.method3).to eql 'ensure equivalent block'
end
end

How to test exception raising in Rails/RSpec?

There is the following code:
def index
#car_types = car_brand.car_types
end
def car_brand
CarBrand.find(params[:car_brand_id])
rescue ActiveRecord::RecordNotFound
raise Errors::CarBrandNotFound.new
end
I want to test it through RSpec. My code is:
it 'raises CarBrandNotFound exception' do
get :index, car_brand_id: 0
expect(response).to raise_error(Errors::CarBrandNotFound)
end
CarBrand with id equaling 0 doesn't exist, therefore my controller code raises Errors::CarBrandNotFound, but my test code tells me that nothing was raised. How can I fix it? What do I wrong?
Use expect{} instead of expect().
Example:
it do
expect { response }.to raise_error(Errors::CarBrandNotFound)
end
In order to spec error handling, your expectations need to be set on a block; evaluating an object cannot raise an error.
So you want to do something like this:
expect {
get :index, car_brand_id: 0
}.to raise_error(Errors::CarBrandNotFound)
See Expect error for details.
I am a bit surprised that you don't get any exception bubbling up to your spec results, though.
get :index will never raise an exception - it will rather set response to be an 500 error some way as a real server would do.
Instead try:
it 'raises CarBrandNotFound exception' do
controller.params[:car_brand_id] = 0
expect{ controller.car_brand }.to raise_error(Errors::CarBrandNotFound)
end

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