CSC/ECE 517 Fall 2012/ch1b 1w39 sn

Setup test environment in Rails

Rails provides a basic boiler plate to create tests.There are three environments provided by Rails - production,development and testing.As the names suggest they are used for different purposes.This prevents developers from messing with their development environments.Inside the rails app directory there will be a directory called test.This directory contains folders-unit,functional,integration and fixtures.The unit folder holds tests for the models, the functional folder is meant to hold tests for your controllers, and the integration folder contains tests that involve any number of controllers interacting.Fixtures contain the sample test data.Rails has the Test::Unit included by default but there are other frameworks also available like RSpec<ref>http://rspec.info/</ref>,Cucumber(for behavior driven development),Shoulda <ref>https://github.com/thoughtbot/shoulda#readme</ref>

Initial setup:

If the application was created using the scaffold command then it should create a stub in test/unit directory.The initial code would look something like this

require 'test_helper'
 
class PostTest < ActiveSupport::TestCase
  # Replace this with your real tests.
  test "the truth" do
    assert true
  end
end

Now if we wanted to add real tests to it then let us take two scenarios 1.Post with empty entries. 2.Post with actual entries The code for these two test cases would look something like this

require 'test_helper'

class PostTest < ActiveSupport::TestCase

  test "Post new empty" do
    p = Post.new
    assert !p.save, "Saved post without title, content, user, or category"
    assert p.invalid?
  end

  test "Post new correct" do
    p = Post.new
    #Post has following fields title,email,content
    p.title = 'General title'
    p.content = 'A new content'
    p.email = 'Azrael@ncsu.edu'
    #place an assert .so as to find out whether this statement is valid or not
    assert p.valid?
  end

end

test_helper.rb contains the default configuration to run the tests,ActiveSupport::TestCase defines the basic methods for defining a test case.The test cases must begin with the name "test". The statement that actually determines whether the test has passed or not is the assert statement.An assertion is a line of code that evaluates an object (or expression) for expected results.It can check a variety of things like is the expression true or false,is it valid etc. In this example, in the first test case we are checking whether p is an invalid object,if yes then the test has passed because that is the expected thing.Whereas the second test checks whether p is an valid object or not,if its not then the test fails as the expected output in this case is that p should be a valid object. After the test cases have been written there are a few things we need to prepare the test db.

 rake db:migrate
 rake db:test:load

This two commands should suffice but a complete reference of rake commands for testing purpose is mentioned in <ref>http://guides.rubyonrails.org/testing.html#preparing-your-application-for-testing</ref> After preparing everything we are now ready to run our test.If you are using a Integrated Development Environment(IDE) like RubyMine then you need not worry anything and just press Run->select your test as shown in the figure