How to make Ruby Mocha mock only check about one parameter - ruby

I want to mock this function:
def self.set_segment_info(segment_info, history_record)
history_record.segment_info = segment_info
end
In my test, I want a mock that only confirms that I called set_segment_info with an expected value. I don't care about what I pass in for history_record.
How would I do this? I tried
SegmentHistoryRecord.expects(:set_segment_info).with(:segment_info => expected_segment_info, :history_record => anything)
But that doesn't work.

I ran into this today and ended up doing something like:
SegmentHistoryRecord.expects(:set_segment_info).with(
expected_segment_info,
anything
)
I find it more readable that the do version and it helped me avoid a rubocop issue with too many parameters.

Here's an implementation where, if your function takes a lot of parameters, it's more convenient to specify a value for just the one you care about, instead of for all of them:
expected_segment_info = # ...
SegmentHistoryRecord.expects(:set_segment_info).with() { |actual_parameters| actual_parameters[:segment_info] == expected_segment_info }
(Where, as in the original question, set_segment_info is the function being mocked, and segment_info is the parameter whose value you want to match. Note that the history_record parameter -- and any others that might be present -- don't need to be included.)

SegmentHistoryRecord.expects(:set_segment_info).with() do |param1, param2|
# change below to your verification for :segment_info
# and leave param2 doing nothing, the expectation will ignore param2
param1 == expected_segment_info
end

Related

Better ternary condition

Method find_something may return nil. In the following code,
something = find_something(id) ? find_something(id) : create_something(foo)
find_something(id) is called twice. This is a smell that I want to avoid. Is there a way to avoid redundancy in this expression?
Anything like this?
something = find_something(id) || create_something(foo)
There's not quite enough detail given to say this with confidence, though it might be this is a case for find_or_create_by.
If this does suit, you would just do:
something = YourModel.find_or_create_by(id: id)
You can also provide a block to this, which is passed to the create method if no record is found. For example:
something = YourModel.find_or_create_by(id: id) do |instance|
# this block only gets executed on create
instance.some_new_attribute = 'goes here'
end
Hope that's useful - let me know if it suits your use case.

How to use polymorphism to remove a switch statement which compares strings?

I am new to Ruby, so let me describe the context of my problem first:
I have a json as input which has the following key / value pair:
{
"service": "update"
}
The value has many different values for example: insert,delete etc.
Next there is a method x which handles the different requests:
def x(input)
case input[:service]
services = GenericService.new
when "update"
result = services.service(UpdateService.new,input)
when "insert"
result = services.service(InsertService.new,input)
when "delete"
result = services.service(DeleteService.new,input)
....
....
else
raise "Unknown service"
end
puts JSON.pretty_generate(result)
end
What is bothering me is that I still need to use a switch statement to check the String values (reminds me of 'instance of' ugh..). Is there a cleaner way (not need to use a switch)?
Finally I tried to search for an answer to my question and did not succeed, if however I missed it feel free to comment the related question.
Update: I was thinking to maybe cast the string to the related class name as follows: How do I create a class instance from a string name in ruby? and then call result = services.services(x.constantize.new,input) , then the class names ofcourse needs to match the input of the json.
You can try something like:
def x(input)
service_class_name = "#{input[:service].capitalize}Service"
service_class = Kernel.const_get(service_class_name)
service_class.new(input).process
end
In addition you might want to check if this is a valid Service class name at all.
I don't understand why you want to pass the service to GenericService this seems strange. let the service do it's job.
If you're trying to instatiate a class by it's name you're actually speaking about Reflection rather than Polymorphism.
In Ruby you can achieve this in this way:
byName = Object.const_get('YourClassName')
or if you are in a Rails app
byName= 'YourClassName'.constantize
Hope this helps
Just first thoughts, but you can do:
eval(services.service("#{input[:service].capitalize}Service.new, #{input})") if valid_service? input[:service]
def valid_service?
w%(delete update insert).include? input[:service]
end
As folks will no doubt shout, eval needs to be used with alot of care

RSpec - trying to stub a method that returns its own argument

I have a method which I'm trying to stub out in my unit test. The real method gets called with one argument (a string) and then sends out a text message. I need to stub out the method but return the string that gets passed in as an argument.
The code I have in my RSpec test is this:
allow(taxi_driver).to receive(:send_text).with(:string).and_return(string)
This returns:
NameError: undefined local variable or method 'string'
If I change the return argument to :string, I get the following error:
Please stub a default value first if message might be received with other args as well
I've tried googling and checking the relishapp.com site, but can't find the answer to something which appears quite simple and straightforward.
You can pass a block:
allow(taxi_driver).to receive(:send_text).with(kind_of(String)){|string| string }
expect(taxi_driver.send_text("123")).to eq("123")
My method is being called like this: send_text("the time now is #{Time.now}"). The string varies according to the time, thats why I need the mock to return the varying string. Perhaps its not within the scope of a mock to do this?
In such a case, I usually use Timecop gem in order to freeze system time. Here is a sample use case:
describe "#send_text" do
let(:taxi_driver) { TaxiDriver.new }
before do
Timecop.freeze(Time.local(2016, 1, 30, 12, 0, 0))
end
after do
Timecop.return
end
example do
expect(taxi_driver.send_text("the time now is #{Time.now}")).to eq \
"the time now is 2016-01-30 12:00:00 +0900"
end
end

How to pass special parameters in a function in Ruby Selenium Webdriver

I'm using Selenium Webdriver Ruby to create a function in order to wait for an element displayed within a Time that I set in this function
My function will have two parameters (one Optional parameter & one parameter is locator name of an object)
So, I have my function with two parameters like below:
def wait_for_element_displayed(locator, options={})
if options[:time]
settime = options[:time]
else
settime= 60
end
#driver.find_element(locator).click
end
So, I will call this function like: wait_for_element_displayed(:id=>"unique1", :time => "20")
However, I got the error when trying to calling this function with this way, the error is: "TypeError: can't convert String into an exact number".
Anybody please help me how to pass two parameters like my scenario to a function? Any help appreciated.
A few suggestions:
You can use hash#fetch to set a default value if the key you are looking up is not present:
time = options.fetch(:time) { 60 }
Ruby will have a hard time parsing your input when both arguments are hashes and you don't differentiate between them. Also, your error makes me think you should provide 20 as an integer instead of a string. Try calling the method like this:
wait_for_element_displayed({:id => "unique1"}, { :time => 20 })
Lastly, I don't know much about Selenium, so maybe someone can fill me in on the last point. Is setting a settime variable sufficient to configure timeouts?

How do I elegantly handle nil cases in my array assignment - Ruby?

So I am pushing some elements on my array like this:
upd_city_list << [ j.children[0].text.strip!.gsub(/\s+\W/, ''), j.children[1].text, j.children[1][:href] ]
The above is in an iterator (hence the use of j).
The issue is that from time to time, the j.children[0].text turns up as nil, and Ruby doesn't like that.
I could add a bunch of if statements before this assignment, but that seems a bit inelegant to me.
How do I handle nil cases in this situation in an elegant way?
One possible solution is, when there is a nil value, just push the string none onto the array....but what would that look like?
Thanks.
Edit1:
This is the error I am getting:
NoMethodError: private method ‘gsub’ called for nil:NilClass
The real problem is that strip! returns nil when there are no changes to the string. Your text method is returning a string, it is your strip! method is returning nil. I don't know why it does this. I dislike it, too.
This case of the problem will go away if you just change strip! to strip
In a more general sense, you might create an object to return the array for you. You don't want to go changing (what I assume is) Nokogiri, but you can wrap it in something to hide the train wrecks that result.
You should replace j.children[0].text.strip! with one of two things:
(j.children[0].text || 'none').strip
or
j.children[0].text.to_s.strip
These will, of course, have different effects when the text is nil. I think your ACTUAL problem is that strip! was returning nil, and that should have been obvious to you from the error message.
This might be the case for one to use null object programming pattern. Nil is not a good null object. Try reading here and here. Null object is the elegant way.
nil or a_string will be a_string
so what about (j.children[0].text or 'none')
If you're in rails, this is a great use for the try method.
Also seems that your strip and gsub are redundent. Please consider this implementation:
descriptive_name_1 = j.children[0].text.try(:strip)
descriptive_name_2 = j.children[1].text
descriptive_name_3 = j.children[1][:href]
updated_city_list << [ descriptive_name_1 , descriptive_name_2, descriptive_name_3 ]
w/o try
descriptive_name_1 = j.children[0].text.to_s.strip
descriptive_name_2 = j.children[1].text
descriptive_name_3 = j.children[1][:href]
updated_city_list << [ descriptive_name_1 , descriptive_name_2, descriptive_name_3 ]
If you're in the rails environment you could try try method: https://github.com/rails/rails/blob/82d41c969897cca28bb318f7caf301d520a2fbf3/activesupport/lib/active_support/core_ext/object/try.rb#L50

Resources