Code Academy Week 11 Notes

2012-03-20_08.52.33
Look at rspec
to not include default testing framework:

rails new AppName -T

In Gemfile:

gem 'rspec-rails'
ericm@finance:~/ruby/MeatdownApp$ rails g rspec:install
      create  .rspec
      create  spec
      create  spec/spec_helper.rb
rails g model User name:string
      invoke  active_record
      create    db/migrate/20120320135609_create_users.rb
      create    app/models/user.rb
      invoke    rspec
      create      spec/models/user_spec.rb
ericm@finance:~/ruby/MeatdownApp$ rake db:test:prepare

to update test database

History for rails and rspec project:

2005  rails new MeatdownApp -T
 2006  cd MeatdownApp/
 2007  bundle install
 2008  rails g rspec:install
 2009  rails g model User name:string
 2010  rake db:migrate
 2011  rspec spec/models/
 2012  bundle install
 2013  rspec
 2014  rake db:test:prepare
 2015  rspec
 2016  gem list --local
 2017  bundle install
 2018  rspec
 2019  bundle install
 2020  rspec
 2021  bundle exec install
 2022  bundle exec
 2023  ruby -v
 2024  rails g model Meetup title:string
 2025  rake db:migrate
 2026  rake db:test:prepare
 2027  cp -v /home/ericm/github/digital_schoolhouse/.rvmrc .
 2028  emacsnw .rvmrc
 2029  cd ../
 2030  cd MeatdownApp/
 2031  bundle install
 2032  rspec
 2033  rails g migration AddUserIdToMeetup user_id:integer
 2034  rake db:migrate
 2035  more db/schema.rb
 2036  rake db:test:prepare
 2037  rake
 2038  rspec
 2039  history

 

Dave Hoover
He had to create his own software engineering education
His advice:
1. seek out mentors
2. kindred spirits
3. Community

He tries to be the worst person on the team
Keep diving deeper into Rails, know about testing
he uses TestUnit – no RSpec back then
Expand your bandwidth, drink from the firehose
Learning is fun, but debugging may not be
Learn how to expand/contract your bandwidth
After Code Academy: Don’t be discouraged
Very few people just walk right into a job
It takes some time
Reach out, ask people in the community, find out what is out there
Apprentice: 8th Light, Groupon, Trunk Club
You will need to hustle

——
.rspec file:

--format nested
--color

We want a model without a database table

rails g model CoinChanger --no-migration

No migration generated, but it still has ActiveRecord in it

class CoinChanger < ActiveRecord::Base
end

so take out “< ActiveRecord::Base”

If you just run “rake”, it will run your tests
Jeff do not test your views, just your models and controllers

2012-03-22_08.30.05
Modules: you can include or extend a module
you can extend a module and use its methods as class methods by calling with “extend”
in irb: you can require or include files

require "./modules"

if it is in same dir from which you called irb
You could also “load” a file

load "modules.rb"

This will reload the file if you call it again
in the file you can call “require relative ‘modules'” which goes from pwd of the file
Modules extend a class that extends Kernel

It is better to use composition than inheritance many times
inheritance cements the relationships. It only works for one kind of re-use: is-a

In modules you can make a method self.method_name and you can make those available at module level
No instance needed

self keyword: it refers to the current object
class scoped code is executed when code is read/loaded/class initialized
It is only run once

class Table
end
puts self

That second self will print “main” even though you are not in a class, “out in hyperspace” as Jeff puts it

In class scope, self returns name of table, inside an instance method, self refers to the instance

— look for a “collect” method

We could make a method called “method_missing” that will handle any calls to undefined methods

def method_missing(m, *args )
end

m is a symbol that is the name of the ghost method
*args is an array of args

def method_missing(m, *args )
  puts "whoa! you tried to call #{m.to_s}, with these args:"
  puts args.inspect
end

This may be how Rails does find_by_column name:
it uses regular expressions in method_missing

You could also call super in method_missing

Another use of modules: namespacing

module Jeff
  class Boat
  end
end
b1 = Jeff::Boat.new
b2 = John::Boat.new

If you have two classes with the same name, you will get the union of the classes
If the same method name is used, the last method defined wins

You could add to String, Array, Hash

modules package stuff for re-use and good for namespacing

You can call instance.respond_to?(length) to see if it will respond to that method call

s = "Hello"
s.respond_to?(:length)
s.send(:length)

You may get stuff in a variable

gem list acti

will give the gems with “acti” in the name

gem which will_paginate

will tell you where the gem was installed

gem list -d activesupport

In rails apps, there is a lib/tasks directory
Make a file called flights.rake

it must go in a block

task :jeff do
  puts "hi"
end

Then you can call “rake jeff”
To see in the list, put
desc “sample rake task”
in the file – before line with :task

task :prereq do
end

task :jeff => :prereq do
end

This will make the :jeff task run the :prereq task first

What if you deal with models?

task :list => :environment do
  puts "We have #{Airport.count} airports"  
end

You can namespace your tasks

namespace :air do
  task :jeff do
  end
end

Image from World Digital Library, assumed allowed under Fair Use. Image from the Psalter of Frederick II, a 13th century manuscript in the Byzantine style, housed at Riccardiana Library of Florence, aka Biblioteca Riccardiana.

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