Question

I have the following test, with two almost identical blocks. Now i am looking for ways to refactor this cleanly.

The test:

context "with the d1 configuration" do
  before (:each) do
    # send a message 
    @envelope = Factory(:envelope, :destination => '32495xxxxxx', :message => 'Message sent by d1')
    @distributor = Distributor.find_by_name(Distributor::D1)
    @result = @envelope.send_to(@distributor)
  end
  it "should created a new sms-message" do
    @envelope.sent_messages.size.should == 1
  end

  it "should have created one sms-message linked to the envelope and distributor" do
    sms = @envelope.sent_messages.find_by_distributor_id(@distributor.id)
    sms.should be_instance_of(SentMessage)
    sms.external_message_id.should_not == nil
    sms.sent_message_status_id.should == SentMessageStatus::IN_PROGRESS
  end

  it "should add a logline for the creation of the sms-message" do
    @envelope.log_lines.size.should == 2
    @envelope.log_lines.last.message.should =~ /^Sent message/
  end
end


context "with the correct d2 configuration" do
  before (:each) do
    # send a message 
    @envelope    = Factory(:envelope, :destination => '32495xxxxxx', :message => 'Message sent by d2')
    @distributor = Distributor.find_by_name(Distributor::D2)
    @result = @envelope.send_to(@distributor)
  end
  it "should created a new sms-message" do
    @envelope.sent_messages.size.should == 1
  end

  it "should have created one sms-message linked to the envelope and distributor" do
    sms = @envelope.sent_messages.find_by_distributor_id(@distributor.id)
    sms.should be_instance_of(SentMessage)
    sms.external_message_id.should_not == nil
    sms.sent_message_status_id.should == SentMessageStatus::IN_PROGRESS
  end

  it "should add a logline for the creation of the sms-message" do
    @envelope.log_lines.size.should == 2
    @envelope.log_lines.last.message.should =~ /^Sent message/
  end
end

As you can tell, two identical code blocks, each for a different distributor, D1 and D2 (in our project they have more meaningful names :)) — and now i need to add a third distributor. How do i go about this?

I can loop over an array containing the changing parts (in this case: distributor-name and the message contents). But can i also change the test-name?

What are the best approaches here? Is it possible to make some kind of test-template, where you can fill in certain values and execute that?

Answer 1

Yes, you can loop through an array/hash full of examples and yes you can rename contexts based on that but you’ll have to be aware of scoping issues – eg a context is a class-level scope, but a test is an instance.
Thus you have to setup these things in instance-variables in the “setup” section of a context.
I’ve mainly done this stuff with unit:test+shoulda (rather than rspec) so I may have messed up the scoping rules somewhat, but they should be similarish

Note: I haven’t tested the code below, so it may be prey to such issues…

# name this better than I have    
CONFIGS = {'d1' => {:name => Distributor::D1
                    :destination => '32495xxxxxx',
                    :message => 'd1 message'}, 
           'd2' => {:name => Distributor::D2
                    :destination => '98765xxxxxx',
                    :message => 'd2 message'}
           } # etc

CONFIGS.each do |display_name, dist_hash|
  context "with the #{display_name} configuration" do
    before (:each) do
      # scope the value-hash here to make it available to test-cases 
      # (you don't have to if you're just using it in the setup section)
      @dist_hash = dist_hash
      # send a message 
      @envelope = Factory(:envelope, :destination => @dist_hash[:destination], :message => @dist_hash[:message])
      @distributor = Distributor.find_by_name(@dist_hash[:name])
      @result = @envelope.send_to(@distributor)
    end
    it "should created a new sms-message" do
      @envelope.sent_messages.size.should == 1
    end

    it "should have created one sms-message linked to the envelope and distributor" do
      sms = @envelope.sent_messages.find_by_distributor_id(@distributor.id)
      sms.should be_instance_of(SentMessage)
      sms.external_message_id.should_not == nil
      sms.sent_message_status_id.should == SentMessageStatus::IN_PROGRESS
    end

    it "should add a logline for the creation of the sms-message" do
      @envelope.log_lines.size.should == 2
      @envelope.log_lines.last.message.should =~ /^Sent message/
    end
  end
end