I find mocking things with RSpec to be entirely problematic and I often don't know how much code to include, in terms of it being diagnostic. So I'll start with the situation I have and the code that I've isolated as causing the problem.
I have tests where I need to mock a browser. I have a mock driver I set up like this:
require "watir"
def mock_driver
browser = double("watir")
allow(browser).to receive(:is_a?).with(Watir::Browser).and_return(true)
allow(browser).to receive(:driver).and_return(true)
browser
end
The only problems I have in my test suite are these two tests:
context "an empiric driver is requested" do
it "a watir browser is provided" do
allow(Watir::Browser).to receive(:new).and_return(Empiric.browser)
Empiric.set_browser mock_driver
end
it "the requested watir browser can be shut down" do
#allow(Empiric.browser).to receive(:quit)
Empiric.quit_browser
#allow(mock_browser).to receive(:new).and_return(Empiric.browser)
#Empiric.set_browser mock_driver
end
end
(The commented out bits in the second test are on purpose to illustrate what's going on.)
With that one line in place in the second test, I get the following error on that test:
<Double "watir"> was originally created in one example but has leaked into another
example and can no longer be used. rspec-mocks' doubles are designed to only last for
one example, and you need to create a new one in each example you wish to use it for.
If I entirely comment out the first test above, that error doesn't happen so I know I've isolated the two tests that are interacting with each other.
Okay, now notice the final line of my second test that is commented out. That seems to be what the error is indicating to me. It's saying I need to create a new double in the other. Okay, so I'll change my last test:
it "the requested watir browser can be shut down" do
#allow(Empiric.browser).to receive(:quit)
Empiric.quit_browser
#allow(mock_browser).to receive(:new).and_return(Empiric.browser)
Empiric.set_browser mock_driver
end
So here I've uncommented the last line so I'm establishing the mock_driver in that test and not allowing the code to leak.
That, however, returns exactly the same error on exactly the same test.
I'm not sure if it would help to see the methods that are being called in that test, but here they are. First is set_browser:
def set_browser(app = :chrome, *args)
#browser = Watir::Browser.new(app, *args)
Empiric.browser = #browser
end
And here is quit_browser:
def quit_browser
#browser.quit
end
The fact that RSpec thought one test was "leaking" into the other made me think that perhaps my #browser instance was the problem, essentially being what's persisting between the two tests. But I don't see how to get around that. I thought that maybe if I quit the browser in the first test, that would help. So I changed the first test to this:
it "a watir browser is provided" do
Empiric.quit_browser
allow(Watir::Browser).to receive(:new).and_return(Empiric.browser)
Empiric.start_browser mock_driver
end
That, however, led to the above error being shown on both tests now.
My more likely accurate guess is that I simply don't know how to provide a mock in this context.
I think you have to use allow with the mock and not Watir::Browser.
For example, what happens if you allow the mock browser to receive whatever calls the browser would and have the it return the mock browser?
Right now you're allowing the "Watir::Browser" to receive those messages and that's returning an "Empiric.browser". Looking at your code, I understand why you put that in there but I think that might be what's screwing you up here.
Mocks in RSpec are horrible things that rarely if ever work correctly in situations like this. I would entirely recommend not using the mock_driver that you have set up. Rather, for each of your tests just do something similar to what you are doing in the mock_driver. My guess is you're including the mock driver as part of a shared context and that, too, is another thing that is very fragile in RSpec. Not recommended.
Instead you might want to use contexts to break up your tests. Then for each context block have a before block. I'm not sure if you should use before:all or before:each given that you're simulating a browser. But that way you can set up the browser in the before and tear it down in an after.
But I would recommend getting it working in each test individually first. Even if it's a lot of code duplication. Then once all tests are passing, refactor to put the browser stuff in those before/after blocks.
But, again, don't use mocks. Don't use shared contexts. It never ends well and honestly it makes your tests harder to reason about.
Given some advice from Micah, I wanted to provide an answer with a solution. I ended up doing this:
context "an empiric driver is requested" do
it "a watir browser is provided" do
allow(Watir::Browser).to receive(:new).and_return(Empiric.browser)
allow(Empiric.browser).to receive(:driver).and_return(true)
expect { Empiric.start_browser :some_browser }.not_to raise_error
end
it "the requested watir browser can be shut down" do
allow(Empiric.browser).to receive(:quit)
allow(Watir::Browser).to receive(:new).and_return(Empiric.browser)
allow(Empiric.browser).to receive(:driver).and_return(true)
expect { Empiric.quit_browser }.not_to raise_error
end
end
All of that was needed as it is or I would get some error or other. I removed my mock driver and, per Micah's suggestion, simply tried to incorporate what seemed to work. The above "contraption" is what I ended up with as the sweet spot.
This works in the sense of giving coverage of the methods in question. What was interesting was that I had to add this to my RSpec configuration:
RSpec.configure do |config|
config.mock_with :rspec do |mocks|
mocks.allow_message_expectations_on_nil = true
end
end
I needed to do this because RSpec was reporting that I was calling allowing something that was nil to receive a value.
This brought up some interesting things, if you think about it. I have a test that is clearly passing. And it adds to my code coverage. But is it actually testing the quit action on a browser? Well, not really since it was testing a quit action on something that it thought was nil.
But -- it does work. And it must be calling the lines of code in question because the code coverage, as reported my SimpleCov, indicates that the statements in question have been checked.
Related
Perhaps it is my lack of familiarity with rspec but i do not understand what is going on with my test.
I have 2 classes one called Scrape, the other Result (creative) Scrape is a web scraping class that searches a site and scrapes the results from the page, creating a new Result instance from each.
Result instances are stored in a class variable array accessible via Result.all
this works in practice in the actual program, however when I tried to write a test for this behavior it fails.
describe "#scrape_results" do
it "accepts a url scrapes the page and creates a Result for each" do
s = Scrape.new
s.scrape_results(#url)
expect(Result.all.count).not_to eq(0)
end
end
every time i run the test Result.all.count is 0
if i use pry and manually run #scrape_results the test passes.
I appreciate your time, patience, and help
thanks
I notice that you are passing #url to #scrape_results in your test. Unless you are defining that variable inside of the describe block or the test block it will be nil in your test. It is possible that since #url might be something other than nil from wherever you are pry-ing which is causing the Result to be created and the test to pass.
I have a Ruby cli program that can optionally load a user-specified file via require. I would like to unit test this functionality via RSpec. The obvious thing to do is to mock the require and verify that it happened. Something like this:
context 'with the --require option' do
let(:file) { "test_require.rb" }
let(:args) { ["--require", "#{file}"] }
it "loads the specified file"
expect(...something...).to receive(:require).with(file).and_return(true)
command.start(args)
end
end
(That's just typed, not copy/pasted - the actual code would obscure the question.)
No matter what I try, I can't capture the require, even though it's occurring (it raises a LoadError, so I can see that). I've tried a variety of things, including the most obvious:
expect(Kernel).to receive(:require).with(file).and_return(true)
or even:
let(:kernel_class) { class_double('Kernel') }
kernel_class.as_stubbed_const
allow(Kernel).to receive(:require).and_call_original
allow(Kernel).to receive(:require).with(file).and_return(true)
but nothing seems to hook onto the require
Suggestions?
So require is defined by Kernel but Kernel is included in Object so when you call require inside this context it is not necessarily the Kernel module that is processing the statement.
Update
I am not sure if this exactly solves your issue but it does not suffer from the strange behavior exhibited below:
file = 'non-existent-file'
allow(self).to receive(:require).with(file).and_return(true)
expect(self).to receive(:require).with(file)
expect(require file).to eq(true)
Working Example
OLD Answer:
This is incorrect and exists only for posterity due to the up-votes received. Some how works without the allow. Would love it if someone could explain why as I assumed it should raise instead. I believe the issue to be related to and_return where this is not part of the expectation. My guess is we are only testing that self received require, with_file, and that the and_return portion is just a message transmission (thus my updated answer)
You can still stub this like so:
file = 'non-existent-file.rb'
allow_any_instance_of(Kernel).to receive(:require).with(file).and_return(true)
expect(self).to receive(:require).with(file).and_return(true)
require file
Since I am unclear on your exact implementation since you have obfuscated it for the question I cannot solve your exact issue.
I'm working on some unit tests. One of them use a specific configuration variable as set in my application MyBigApp::Env which looks like:
{:country=>'uk', :another_hosts=>["192.168.99.105"]}
So I access it with MyBigApp::Env.country
However in my unit test I want that country for the test become something.
Using rspec I've seen stub but can't get it to work - any ideas where I'm going wrong:
MyBigApp::Env.stub(:[]).with('country').and_return('gr')
Also tried this (as above shows deprecated):
allow(MyBigApp::Env).to receive('country').and_return('gr')
Infact as a test, I also tried:
my_hash = {:uri=>nil}
allow(my_hash).to receive(:[]).with(:uri).and_return('Over written!')
p my_hash
and that didnt update either - it just returned {:uri=>nil}
As a workaround, at the moment I'm having to save the env var in a temp var in the before(each) block then return it back to the original in the after(each). This feels really risky to me. I'm thinking imagine the service running and someone runs unit tests it could effect the end user in that small instance the test is running.
Any help would be appreciated.
Thanks
Yes it possible, but keep in mind that stub only works when you trigger/call the method that you stubbed/mocked
my_hash = {:uri=>nil}
allow(my_hash).to receive(:[]).with(:uri).and_return('Over written!')
p my_hash[:url] # it will be 'Over written!'
This works for me:
my_hash = {:uri=>nil}
allow(my_hash).to receive(:[]).with(:uri).and_return('Over written!')
expect(my_hash[:uri]).to eq "Over written!"
In your sample test case, you are just calling p my_hash which doesn't actually call the [] method.
In terms of why this isn't working with MyBigApp::Env, well, that really depends on what class it is. Possible whatever method .country is doesn't actually call [].
Really, if you call MyBigApp::Env['country'] and stub MyBigApp::Env to receive [] with 'country', it should work.
In regards to your concern about changing your running application's behavior from the tests ... what kind of tests are these?! Running unit tests against a live production application would be very odd. How do you imagine it would change your production app's code? The Env hash just lives in memory right?
Anyway, you should never have to worry about your tests changing the experience for an 'end user'. Always run tests on a completely quarantined envionment, meaning don't use the same database. Actually, the test database is usually wiped after each test.
Just wanted to suggest a non-stubbing alternative. For example:
def code_under_test
key = 'country'
# ... maybe lots of code
value = MyBigApp::Env[key] # deep inside some classes
# ... lots more code
"This is the #{value}"
end
MyBigApp::Env is hard-coded deep in the code, and the need for stubbing reveals that dependency, and the benefits of OOP encapsulation are lost.
It'd be much easier if this were the case:
def code_under_test(config_vars = MyBigApp::Env)
"This is the #{config_vars['country']}"
end
it 'should return my country value' do
value = previous_code_under_test('country' => 'TEST VALUE')
expect(value).to eq("This is the TEST VALUE")
end
No stubbing required, just plain old method calls.
I'm testing a nightmarish website that in most situations sticks all the important stuff in an iframe.
However, there are other common situations where the system will, annoyingly, open a page in a new tab, but not wrapped in the iframe.
I'm trying to figure out a conditional method that will check for the existence of the iframe and use it, otherwise not.
Here's what I've come up with, so far:
# The browser object...
#br = Watir::Browser.new
"frm" is the conditional method I'm trying to get working...
# Just an example element definition...
def click_my_button
#br.frm.button(id: "button").click
end
I define it in Watir's Container module, like so:
module Watir
module Container
def frm
if frame(id: "iframeportlet").exist?
frame(id: "iframeportlet")
else
# This is the part that I can't figure out.
end
end
end
end
That works fine when the iframe is there, but not surprisingly I get a NilClass error when it's not.
So, my question is: what can go into the else clause to make it work? More broadly, is there perhaps a better way to accomplish this? As you can imagine, I really want to avoid having to define every element in the web site twice.
I figured it out, and it's quite simple. The frm method's else clause just needs a "self"...
else
self
end
That's it. I'd love to know if there are any hidden pitfalls with this approach, though.
I have to say I am new both to Ruby and to RSpec. Anyway I completed one RSpec script but after refactoring it failed. Here is the original working version:
describe Site do
browser = Watir::Browser.new :ie
site = Site.new(browser, "http://localhost:8080/site")
it "can navigate to any page at the site" do
site.pages_names.each do |page_name|
site.goto(page_name)
site.actual_page.name.should eq page_name
end
end
browser.close
end
and here is the modified version - I wanted to have reported all the pages which were visited during the test:
describe Site do
browser = Watir::Browser.new :ie
site = Site.new(browser, "http://localhost:8080/site")
site.pages_names.each do |page_name|
it "can navigate to #{page_name}" do
site.goto(page_name)
site.actual_page.name.should eq page_name
end
end
browser.close
end
The problem in the latter case is that site gets evaluated to nil within the code block associated with 'it' method.
But when I did this:
...
s = site
it "can navigate to #{page_name}" do
s.goto(page_name)
s.actual_page.name.should eq page_name
end
...
the nil problem was gone but tests failed with the reason "browser was closed"
Apparently I am missing something very basic Ruby knowledge - because the browser reference is not working correctly in modified script. Where did I go wrong? What refactoring shall be applied to make this work?
Thanks for your help!
It's important to understand that RSpec, like many ruby programs, has two runtime stages:
During the first stage, RSpec loads each of your spec files, and executes each of the describe and context blocks. During this stage, the execution of your code defines your examples, the hooks, etc. But your examples and hooks are NOT executed during this stage.
Once RSpec has finished loading the spec files (and all examples have been defined), it executes them.
So...trimming down your example to a simpler form, here's what you've got:
describe Site do
browser = Watir::Browser.new :ie
it 'does something with the browser' do
# do something with the browser
end
browser.close
end
While visually it looks like the browser instance is instantiated, then used in the example, then closed, here's what's really happening:
The browser instance is instantiated
The example is defined (but not run)
The browser is closed
(Later, after all examples have been defined...) The example is run
As O.Powell's answer shows, you can close the browser in an after(:all) hook to delay the closing until after all examples in this example group have run. That said, I'd question if you really need the browser instance at example definition time. Generally you're best off lazily creating resources (such as the browser instance) when examples need them as they are running, rather than during the example definition phase.
I replicated your code above using fake classes for Site and Watir. It worked perfectly. My only conclusion then is that the issue must lie with either one of the above classes. I noticed the Site instance only had to visit one page in your first working version, but has to visit multiple pages in the non working version. There may be an issue there involving the mutation happening inside the instance.
See if this makes a difference:
describe Site do
uri = "http://localhost:8080/site"
browser = Watir::Browser.new :ie
page_names = Site.new(browser, uri).page_names
before(:each) { #site = Site.new(browser, uri) }
after(:all) { browser.close }
pages_names.each do |page_name|
it "can navigate to #{page_name}" do
#site.goto(page_name)
#site.actual_page.name.should eq page_name
end
end
end