Using RSpec, I want to test that certain methods are called within a method. Take the following example class:
class Upload < ActiveRecord::Base
def process
case self.file_name
when /\.html$/
to_pdf
end
end
end
How would I test that to_pdf is called when process is called on an Upload instance with file_name = 'foo.html'? I'd like to do this using a test double if possible.
instance = Upload.new
instance.file_name = "foo.html"
instance.should_receive(:to_pdf)
instance.process
Related
I have problem stubbing external api, following is the example
require 'rspec'
require 'google/apis/storage_v1'
module Google
class Storage
def upload file
puts '#' * 90
puts "File #{file} is uploaded to google cloud"
end
end
end
class UploadWorker
include Sidekiq::Worker
def perform
Google::Storage.new.upload 'test.txt'
end
end
RSpec.describe UploadWorker do
it 'uploads to google cloud' do
google_cloud_instance = double(Google::Storage, insert_object: nil)
expect(google_cloud_instance).to receive(:upload)
worker = UploadWorker.new
worker.perform
end
end
I'm trying to stub Google::Storage class. This class is instantiated inside the object being tested. How can I verify the message expectation on this instance?
When I run above example, I get following output, and it seems logical, my double is not used by tested object
(Double Google::Storage).upload(*(any args))
expected: 1 time with any arguments
received: 0 times with any arguments
I'm new to Rspec and having hard time with this, any help will be appreciated.
Thanks!
Reaching for DI is always a good idea (https://stackoverflow.com/a/51401376/299774) but there are sometimes reasons you can't so it, so here's another way to stub it without changing the "production" code.
1. expect_any_instance_of
it 'uploads to google cloud' do
expect_any_instance_of(Google::Storage).to receive(:insert_object)
worker = UploadWorker.new
worker.perform
end
In case you just want to test that the method calls the method on any such objects.
2. bit more elaborated setup
In case you want to control or set up more expectations, you can do this
it 'uploads to google cloud' do
the_double = instance_double(Google::Storage)
expect(Google::Storage).to receive(:new).and_return(the_double)
# + optional `.with` in case you wanna assert stuff passed to the constructor
expect(the_double).to receive(:insert_object)
worker = UploadWorker.new
worker.perform
end
Again - Dependency Injection is clearer, and you should aim for it. This is presented as another possibility.
I would consider reaching for dependency injection, such as:
class UploadWorker
def initialize(dependencies = {})
#storage = dependencies.fetch(:storage) { Google::Storage }
end
def perform
#storage.new.upload 'test.txt'
end
end
Then in the spec you can inject a double:
storage = double
expect(storage).to receive(...) # expection
worker = UploadWorker.new(storage: storage)
worker.perform
If using the initializer is not an option then you could use getter/setter method to inject the dependency:
def storage=(new_storage)
#storage = new_storage
end
def storage
#storage ||= Google::Storage
end
and in the specs:
storage = double
worker.storage = storage
I am starting with DDD and TDD in a Ruby application using Minitest.
I created a repository class (no database access, but it generates the entities for me). It is a singleton.
I would like to test the generation of the entities. The problem is that because it is a singleton, the order of executions of the tests affect the results.
Is there any way to force the disposal of the singleton element so it is "fresh"?
Here is my repository code:
require "singleton"
class ParticipantRepository
include Singleton
def initialize()
#name_count = 0
end
def generate_participant()
participant = Participant.new
participant.name = "Employee#{get_name_count()}"
return participant
end
private
def get_name_count()
old_name_count = #name_count
#name_count += 1
return old_name_count
end
end
And the tests:
require_relative 'test_helper'
class ParticipantRepositoryTest < MiniTest::Unit::TestCase
def setup()
#repository = ParticipantRepository.instance
end
def test_retrieve_participant
participant = #repository.generate_participant
refute_nil participant
refute_nil participant.name
refute_equal("", participant.name)
assert_equal(0, participant.subordinates_count)
end
def test_employee_name_increment
participant1 = #repository.generate_participant
participant2 = #repository.generate_participant
refute_equal(participant1.name, participant2.name)
index_participant1 = /Employee([0-9]+)/.match(participant1.name)[1]
index_participant2 = /Employee([0-9]+)/.match(participant2.name)[1]
assert_equal(0, index_participant1.to_i)
assert_equal(1, index_participant2.to_i)
end
end
The assertion assert_equal(0, index_participant1.to_i) succeeds when test_employee_name_increment is executed first and fails if it is executed last.
I would like to be able to test the repository (because it will evolve into something bigger). How can I do that?
Thanks!
Ordering your tests won't matter. To properly test a singleton class you need to treat it like an instance object. To do that, wrap your singleton in an anonymous Class during setup. Every time setup is called you'll get an untouched copy of the ParticipantRepository:
def setup
#repository = Class.new(ParticipantRepository).instance
end
Call i_suck_and_my_tests_are_order_dependent!() at the top of your
tests when you absolutely positively need to have ordered tests. In
doing so, you’re admitting that you suck and your tests are weak.
...I promise I didn't write this method or the docs.
For more info, see: http://www.ruby-doc.org/stdlib-2.0/libdoc/minitest/rdoc/MiniTest/Unit/TestCase.html#method-c-i_suck_and_my_tests_are_order_dependent-21
I am receiving the following error when running my below ruby script:
s3parse.rb:12:in `block in <class:AccountLog>': undefined method `extract_account_id' for AccountLog:Class (NoMethodError)
I dont think it should be a class method, is there a reason its not taking my method into account?
class AccountLog
attr_accessor :bytes, :account_id, :date
def extract_account_id(line)
line.match(%r{accounts/(\d+)}).captures.join.to_i
end
s3log = File.open('vidcoder.txt').each do |line|
account_log = AccountLog.new
account_log.date = line.match(%r{\[[^:]*}).to_s.delete"[" #need to finish this regex to make it work
account_log.account_id = extract_account_id(line)
account_log.bytes = line.match(%r{^.*\s+HTTP.*\s+-\s+(\d+)\s+}).captures.join.to_i
puts "\n"
puts "The api request on #{account_log.date} was fromm account number #{account_log.account_id} and the bytes were #{account_log.bytes}"
end
end
def extract_account_id will define an instance method.
In the way you call it, you need a class method instead.
Define it like this:
def self.extract_account_id(line)
or, as you already have an AccountLog instance, use it to call extract_account_id:
account_log.account_id = account_log.extract_account_id(line)
Please note that with second way you do not need to alter method definition, just call extract_account_id via account_log instance.
And i guess you would want to put s3log = File... outside class definition.
Or use a constant instead: S3log = ...
Then you'll can access it as AccountLog::S3log
Is there any reason you don't think it should be a class method? You are using it in the context of a class method and that's why it it's saying no such method for class AccountLog.
If you name your method as self.extract_account_id(line) I'm sure it will work.
From what you are trying to do I think this is what you are looking for?
class AccountLog
attr_accessor :bytes, :account_id, :date
def self.extract_account_id(line)
line.match(%r{accounts/(\d+)}).captures.join.to_i
end
end
s3log = File.open('vidcoder.txt').each do |line|
account_log = AccountLog.new
account_log.date = line.match(%r{\[[^:]*}).to_s.delete"[" #need to finish this regex to make it work
account_log.account_id = extract_account_id(line)
account_log.bytes = line.match(%r{^.*\s+HTTP.*\s+-\s+(\d+)\s+}).captures.join.to_i
puts "\n"
puts "The api request on #{account_log.date} was fromm account number #{account_log.account_id} and the bytes were #{account_log.bytes}"
end
While you could take the class method approach, there seems to be a little more going on.
You should put the extraction logic in a method in itself rather than let it hangout in your class. Then outside of the class, have an instance of AccountLog where you can call on the methods for log and account id extraction. At that point you can do something with those values.
Class method or not is a detail we can explore after the class is a bit more clean I think.
I have two classes:
1.Sale is a subclass of ActiveRecord; its job is to persist sales data to the database.
class Sale < ActiveRecord::Base
def self.total_for_duration(start_date, end_date)
self.count(conditions: {date: start_date..end_date})
end
#...
end
2.SalesReport is a standard Ruby class; its job is to produce and graph information about Sales.
class SalesReport
def initialize(start_date, end_date)
#start_date = start_date
#end_date = end_date
end
def sales_in_duration
Sale.total_for_duration(#start_date, #end_date)
end
#...
end
Because I want to use TDD and I want my tests to run really fast, I have written a spec for SalesReport that doesn't doesn't load Rails:
require_relative "../../app/models/sales_report.rb"
class Sale; end
# NOTE I have had to re-define Sale because I don't want to
# require `sale.rb` because it would then require ActiveRecord.
describe SalesReport do
describe "sales_in_duration" do
it "calls Sale.total_for_duration" do
Sale.should_receive(:total_for_duration)
SalesReport.new.sales_in_duration
end
end
end
This test works when I run bundle exec rspec spec/models/report_spec.rb.
However this test fails when I run bundle exec rake spec with the error superclass mismatch for class Sale (TypeError). I know the error is happening because Tap is defined by sale.rb and inline within the spec.
So my question is there a way to Stub (or Mock or Double) a class if that class isn't defined? This would allow me to remove the inline class Sale; end, which feels like a hack.
If not, how do I set up my tests such that they run correctly whether I run bundle exec rspec or bundle exec rake spec?
If not, is my approach to writing fast tests wrong?!
Finally, I don't want to use Spork. Thanks!
RSpec's recently added stub_const is specifically designed for cases like these:
describe SalesReport do
before { stub_const("Sale", Class.new) }
describe "sales_in_duration" do
it "calls Sale.total_for_duration" do
Sale.should_receive(:total_for_duration)
SalesReport.new.sales_in_duration
end
end
end
You may also want to use rspec-fire to use a test double in place of Sale that automatically checks all the mocked/stubbed methods exist on the real Sale class when running your tests with the real Sale class loaded (e.g. when you run your test suite):
require 'rspec/fire'
describe SalesReport do
include RSpec::Fire
describe "sales_in_duration" do
it "calls Sale.total_for_duration" do
fire_replaced_class_double("Sale")
Sale.should_receive(:total_for_duration)
SalesReport.new.sales_in_duration
end
end
end
If you rename total_for_duration on the real Sale class, rspec-fire will give you an error when you mock the method since it doesn't exist on the real class.
A simple way would be to check if "Sale" has already been defined
unless defined?(Sale)
class Sale; end
end
Sale need not be a class either in your test so:
unless defined?(Sale)
Sale = double('Sale')
end
I've got an interesting conundrum. I'm in the midst of developing a library to parse PSDs in Ruby. Also, a buddy is simultaneously working on a library to parse PSDs in JavaScript. We would like to share the same unit tests via a git submodule.
We've decided to use a simple JSON DSL to define each test. A single test might look like:
{
"_name": "Layer should render out",
"_file": "test/fixtures/layer_out.psd",
"_exports_to": "test/controls/layer_out_control.png"
}
So, now it's up to us to build the appropriate test harnesses to translate the JSON into the appropriate native unit tests. I've been using MiniTest to get myself up to speed, but I'm running into a few walls.
Here's what I've got so far. The test harness is named TargetPractice for the time being:
# run_target_practice.rb
require 'target_practice'
TargetPractice.new(:test) do |test|
test.pattern = "test/**/*.json"
end
and
# psd_test.rb
class PSDTest < MiniTest::Unit::TestCase
attr_accessor :data
def tests_against_data
# do some assertions
end
end
and
# target_practice.rb
class TargetPractice
attr_accessor :libs, :pattern
def initialize(sym)
#libs = []
#pattern = ""
yield self
run_tests
end
def run_tests
FileList[#pattern].to_a.each do |file|
test_data = JSON.parse(File.open(file).read)
test = PSDTest.new(test_data["_name"]) do |t|
t.data = test_data
end
end
end
end
Unfortunately, I'm having trouble getting a yield in the initialize to stick in my PSDTest class. Also, it appears that a test will run immediately on initialization.
I would like to dynamically create a few MiniTest::Unit::TestCase objects, set their appropriate data properties and then run the tests. Any pointers are appreciated!
I think you are overcomplicating things a bit here. What you need is a parameterized test, which is pretty trivial to implement using mintest/spec:
describe "PSD converter" do
def self.tests(pattern = 'test/**/*.json')
FileList[pattern].map{|file| JSON.parse(File.read(file))}
end
tests.each do |test|
it "satisfies test: " + test["_name"] do
# some assertions using test["_file"] and test["_exports_to"]
end
end
end