Start writing tests in Ruby: useful gems

April 12, 2016
|In Blog, Ruby on Rails
|By Francisc Kall

Being a QA engineer is a continuous struggle in finding the right resources in order to get the job done easier and more efficiently. If you are planning to write automated tests in RSpec (Ruby’s testing framework), then you should take a look over these gems. Please notice that I am most of the time automating backend tests only, so the libraries I am using are for this purpose mainly.

 

1. RestClient

 

gem install rest-client

If you want to make API calls on RESTful endpoints this should definitely be your choice. This library is easy to use and the response includes code, cookies, headers and body.

Let me show you how to make some calls (GET, PUT, POST, DELETE):

response = RestClient.get(url, header){|response, request, result | response}
response = RestClient.put(url, payload, header){|response, request, result | response}
response = RestClient.post(url, payload, header){|response, request, result | response}
response = RestClient.delete(url, header){|response, request, result | response}

Now you simply use this response for your purposes (response.code, response.body, etc.).

 

2. JSON

 

gem install json

If I told you about RestClient, then the next one should be json. RESTful services will return JSON format in body most of the times so you should parse that response to be easier to work with.

response = RestClient.post(url, payload, header){|response, request, result | response}
parsed_response = JSON.parse(response.body)
expect(parsed_response['errors'][0]['message']).to eq "Not Found"

See how simple this is? You only JSON.parse that response and that’s all!

Since we are talking about JSON, let me show you how to build one:

payload_hash = {
            :key1 => :value1,
            :key2 => :value2
        }
payload_json = payload_hash.to_json

 

3. Nokogiri

 

JSON and XML are the most used formats in web development. So you probably guessed that now I will show you some tricks on how to use XML in your awesome tests.

gem install nokogiri

When I have installed this gem on my ubuntu (v14.04) virtual machine, I have had the following error:

ERROR: Error installing nokogiri:
ERROR: Failed to build gem native extension.

/usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from extconf.rb:4:in `'

But this was quickly fixed after installing ruby-dev and ruby1.9.1-dev:

sudo apt-get install ruby-dev
sudo apt-get install ruby1.9.1-dev

Now let’s say you have the following XML:

<Envelope xmlns="http://schemas.xmlsoap.org/soap/envelope/">
    <Body>
        <Login>
            <username>username</name>
            <password>secret_password</password>
        </Login>
    </Body>
</Envelope>

If you want to access the values for username and password, simply do this:

your_file = Nokogiri::XML(your_XML_file)
your_file.remove_namespaces!
puts your_file.css('username').text
puts your_file.css('password').text

Also, you can use xpath instead of css.

Let me show you how to build the previous XML file using Nokogiri:

builder = Nokogiri::XML::Builder.new do |xml|
  xml.Envelope {
    xml.Body {
      xml.Login {
        xml.username "username"
        xml.password "secret_password"
      }
    }
  }
end
puts builder.to_xml

 

4. Sinatra

 

This gem is used to mock endpoints. See more about it here.

 

5. Dotenv

 

gem install dotenv

It is recommended to keep environment variables and stuff like usernames, passwords and URLs in a .env file. In order to load those variables in your tests, you must use this gem.

Dotenv.load

login_url = ENV['VAR_NAME']
signup_url = ENV['VAR_NAME']

First you load the .env file, then use those variables in your tests.

 

6. Mysql

 

gem install mysql

The name itself says what this is used for. See below how to open a connection to a MySql database and do a simple operation:

con = Mysql.new(db_host, db_user, db_pass, db_schema, db_port)

rs = con.query("UPDATE table_references SET col_name1= ... WHERE where_condition")

con.close

 

I will update this post when I will use some new awesome Ruby library. What gems are you using?

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