RSpec. Part # 1: create tests for the model

As promised, I am starting a series of articles on RSpec.

In this article, I will try to explain in detail how to write tests for models in Ruby on Rails. If you are already familiar with rspec_on_rails, correct and supplement me if something is wrong. Remember that I study Rspec with you and I can be wrong somewhere.

Training

We assume that after reading my previous article, you have already created a test project, configured it and created a schema for it in the database, as well as installed gem rspec. If not, quickly do:

[sudo] gem install rspec
rails ./test -d mysql
nano ./test/config/database.yml
rake db: create

Now, let's move to the directory of our project and execute the command:

./script/generate rspec

Now at the root of our project, we have a spec directory. You can create a direct test for our model, run:

./script/generate rspec_model Post

The rspec will automatically create the model itself, fixtures and migrates for it, as well as a test file with the following contents:

  require File.dirname (__ FILE__) + '/../spec_helper'

 describe Post do
   before (: each) do
     @post = Post.new
   end

   it "should be valid" do
     @ post.should be_valid
   end
 end 

Simple test sample

Well, you can try to get rid of all the tests for the first time, run:

rake spec: models

Oh oh oh, not passed. Rspec says:

  You have 1 pending migrations:
   20090302064129 CreatePosts
 Run "rake db: migrate" to update your database then try again. 

Well, let's do what we are asked for, but before that, let's correct the migration file a bit, to such a state:

  class CreatePosts <ActiveRecord :: Migration
   def self.up
     create_table: posts do | t |
       t.string: name,: limit => 50,: null => false
       t.text: content
       t.timestamps
     end
   end

   def self.down
     drop_table: posts
   end
 end 

Now let's migrate and run the test again:

rake db: migrate
rake spec: models

and voila, our test was successfully passed (if you do not, write in the comments, I will try to help):

.

Finished in 0.040821 seconds
')
1 example, 0 failures

A dot at the beginning means that the test is passed successfully, the letter F means that the test is not passed. Let us now complicate our example a little. Let's change the code a bit:

  it "should require name" do
   @ post.name = nil
   @ post.should_not be_valid
   @ post.errors.on (: name) .should_not be_nil
 end 

After execution, we get:

F

one)
'Post "should require name"' FAILED
expected valid? to return false, got true
./spec/models/post_spec.rb:10:

Finished in 0.045391 seconds

1 examples, 1 failure
rake aborted!

Ok, as long as everything is correct, you need to add validation to our model:

validates_presence_of: name
validates_length_of: name,: within => 3..50

We run again, now everything is OK. The test was successful.

Using Fixtures

Let's edit the file ~ / spec / fixtures / post.yml:

  one:
   id: 1
   name: "this is ferst post"
   content: "tru la la, tra la la"
 two:
   id: 2
   name: "this is second post"
   content: "tran tan tan, tra ta ta" 

Now we change our test, to this type:

  require File.dirname (__ FILE__) + '/../spec_helper'

 describe Post do
   fixtures: posts

   before (: each) do
     @post = Post.new
   end

   it "should require name" do
     @ post.name = nil
     @ post.should_not be_valid
     @ post.errors.on (: name) .should_not be_nil
   end

   it "clears post" do
     posts (: one) .destroy
     lambda {posts (: one) .reload} .should raise_error (ActiveRecord :: RecordNotFound)
   end

 end 

Thus, we loaded all fixtures (posts: posts) and work with them directly, calling them by the symbols (posts (: one)) specified in posts.yml

That's all for now, this should be enough to start writing your own tests for models.
In the following articles, I will discuss the creation of tests for Controllers and Views.