Method run on error with MiniTest - ruby-on-rails

How can I have a method be called on error when using Minitest with Rails, to generate some extra information about the error that just happened?

Have you considered using something like pry or debugger to get more information? I also find liberally sprinkling puts statements throughout the code helpful to ensure that methods I think are being called, are actually called and to show variable values.

This was as simple as:
def teardown
if !passed?
call_method_for_failure
end
end

Related

Accessing rails model through rails console

I was looking to test a method I had created in my "Herd" model. The methods called "safely_assign_herd_usages". I understand how to instantiate a herd e.g. H = Herd.last However, I'm struggling to gain access to the method to test the lines of code within it. Any pointers or help would be greatly appreciated. Thanks.
Use a debugger in the method you want to test.
debug is the standard option.
require 'debug'
def safely_assign_herd_usages
...
binding.break # will interrupt here
...
end
Then in your Rails console, trigger the method to get to the breakpoint:
$ Herd.first.safely_assign_herd_usages
Now the console will load up the method in question and give you an interactive console at that specific spot.

Monkey patching a db model class in Rails with Mongoid causes weird behaviour

I am using a development script file to check out new possible ideas. Recently I tried to monkey patch MyDBObject from within that script file.
Assume an empty dev.rb file and add a monkey patch right in the top like so:
class MyDBObject
def test_function
'function works'
end
end
Starting up the pry console and loading the file yields random results.
First I received:
NoMethodError: undefined method `relations' for MyDBObject:Class
Later the script loaded, but I couldn't access the original class any longer:
undefined method `first' for MyDBObject:Class
I noticed that prepending the line:
MyDBObject
right before the monkey patching, the intended functionality is achieved.
This appears to be some sort of lazy loading of the class objects. Can somebody cast some light on this for me please?
Depending on the order in which source files are loaded, you'll either be redefining the entire class, or having your changes replaced.
I highly recommend giving this a read: http://www.justinweiss.com/articles/3-ways-to-monkey-patch-without-making-a-mess/ (TLDR - put your patch in a module and explicitly include it)

Faker gem - Where is the data being fetched

I'm trying to understand how the Faker rails gem works, so hopefully I can contribute to it. The project is found here: https://github.com/stympy/faker
Under ~/lib/faker/name.rb there will be code like this:
def first_name; fetch('name.first_name'); end
My problem is I don't understand where the hash with all the "name.first_name" is located.
Searching for "def fetch" shows me that the method is defined in lib/faker.rb.
fetch in turn calls translate, which delegates to I8n.translate.

undefined method `rspec_reset' with rspec version 2.14

I am trying execute test cases with rspec version 2.14 for which I am getting following error
undefined method `rspec_reset' for
I am trying to use rspec_reset on the class. The same test cases are working with rspec 2.13.1. So is it possible that rspec_reset method is not available after 2.13?
The reset method does not exist in RSpec 2.14.x. Instead, it is a helper method defined inside the spec_helper.rb file for the rspec-mocks project.
module VerifyAndResetHelpers
def verify(object)
RSpec::Mocks.proxy_for(object).verify
end
def reset(object)
RSpec::Mocks.proxy_for(object).reset
end
end
You can see that this method delegates the reset action to the underlying proxy instead of tacking it on to the class definition of the object in question.
Yes, in 2.14, rspec_reset is no longer available on all objects as it was previously, as discussed in https://github.com/rspec/rspec-mocks/pull/250.
Although I can't find any documentation on it, there now appears to be an RSpec class method reset which takes an object as an argument and will effectively "undo" any RSpec operations that have been done to that object.
There's an RSpec "example" at https://github.com/rspec/rspec-mocks/blob/cee433c89125a3984df33c87eb61985613adce9b/spec/rspec/mocks/mock_spec.rb which still uses the rspec_reset in the description of the example, but which now uses the aforementioned reset method to do the reset. In earlier versions of the example, the reset was done with rspec_reset.

Quickly debug helper methods in script\console

How would I quickly debug helper methods in script\console. I'm talking about making changes and then debugging, over and over again.
This is a lot easier with Model methods, since all I have to do is use
reload!
to test the updated code, whereas to test a helper method, I have to do something like this
foo = ActionView::Base.new
foo.extend YourHelperModule
each time to I want to test a change.
What does reload! do? and can I modify it to add the above lines of code?
I don't think you can do that without hacking Rails. However, there's a workaround - debugging helper method in rails debugger:
1) gem install ruby-debug
2) ruby script/server --debugger
3) place <% debugger %> into some view and open that page in browser
4) server window "turns into" console, where you can debug helper methods
5) 'return' command ends the debugging
If you modify the helper method and run the debugger again, you will get recent version of the method.
More info about debugger is here: http://railscasts.com/episodes/54-debugging-with-ruby-debug
I would suggest not using script console and writing tests in either Test::Unit or rspec instead. Google should get you pointed in the right direction there is a ton of information out there.
If you're doing something "again and again" then you should be automating it. Assuming you know what your helper function should do then as mentioned elsewhere you should be able to write a test (or tests) for it.
Here's a sample that tests application_helper. It lives in my test/unit directory:
require 'test_helper'
class ApplicationHelperTest < ActiveSupport::TestCase
include ApplicationHelper
test "number_as_pct shows 2dp as default" do
assert_equal "1.10%", number_as_pct(0.011)
end
test "number_as_pct shows more dp when required" do
assert_equal "1.1000%", number_as_pct(0.011, :precision => 4)
end
end

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