Simple IRB formatting trick

If you execute IRB with the command line flag –noprompt you will enter in to an IRB session with none of the extra characters showing up on the left side of the terminal. This is great if you want to experiment with code and then use the mouse to copy & paste from it. Like, for example, in a code blog like the one you’re reading…

(Thanks to 6ftdan for this cool tip.)

Rspec tricks for DRY mocked specs

These “tricks” are straight from the docs. One will help DRY up your specs, the other will help you mock your controller for controller tests.

Shared Contexts

Shared context allows for extracting certain setup steps and sharing them across several different sets of tests.

First, define your shared context:

RSpec.shared_context "user setup" do
  let(:user) { User.new(name: 'Chuck Norris') }
  before { allow(user).to receive(:some_method) }
end

Then, include it in your spec files:

describe UsersController do
  include_context 'user setup'
  
  # Tests go here...
end

Anonymous Controllers

Anonymous controllers are a way to specify certain behavior for the controller you are trying to test, or more likely for a parent controller. The thing I found it most useful for, and not coincidentally the thing that the docs says it is useful for, is testing global error handling.

describe UsersController do
  controller do
    def index
      raise AccessDenied
    end
  end

  subject { get :index }

  describe "handling AccessDenied exceptions" do
    it "redirects to the /401.html page" do
      expect(subject).to redirect_to("/401.html")
    end
  end
end

Converting unix timestamps in Ruby

Unix timestamps are common to see in other languages, and also common to see in API responses. Converting a unix timestamp to DateTime in Ruby is dead simple:

unix_timestamp = Time.now.to_i
# => 1453667949
DateTime.strptime(unix_timestamp.to_s, "%s").to_s
# => "2016-01-24T20:39:09+00:00" 

Let’s say your unix timestamp includes milliseconds:

unix_timestamp = (Time.now.to_f * 1000).to_i
# => 1453667949151
DateTime.strptime(unix_timestamp.to_s, "%Q").to_s
# => "2016-01-24T20:39:09+00:00" 


DateTime.strptime will allow you convert just about any formatted time string, see the docs for examples.

Notice how both DateTime strings are the same? DateTime converted to string drops any millisecond data, but keep it as a DateTime object and you can run strftime and display it in any format you like:

DateTime.strptime(unix_timestamp.to_s, "%Q").strftime('%D %T:%L')
# => "01/24/16 20:39:09:151"

Don't wrap specific CSS elements

Another quickie quickie CSS tricky:

Let’s say you’re trying to make a site responsive to many different screen sizes, like you have to these days. You have a block of text that needs to wrap, but you also have a word or number you don’t want to get wrapped. The best example for this I can think of is a phone number – you don’t want it display weird like this:

    Call Jenny today! 800-867-
    5309

Wrap that word or number or whatever in a span and style it with "white-space: nowrap;". Then, that particular element will wrap as one piece:

    Call Jenny today! 
    800-867-5309