Fixtures

Warmup

• What makes testing easy?
• What makes testing hard?
• What challenges are you finding in testing Black Thursday?
• What might be some disadvantages to testing with a large dataset?
• What might be some alternatives?

Fixtures

• Dataset created specifically for our test suite
• Can be difficult to maintain

Fixtures in Practice

• Create a new learning_fixtures directory
• Create lib, test, and data directories
• Download this dataset, and save it in data

Detour: Create a Test Helper

# test/test_helper.rb

require 'minitest'
require 'minitest/autorun'
require 'minitest/pride'

Create a Test

require './test/test_helper'
require './lib/bob'

class BobTest < Minitest::Test
  def test_it_exists
    assert_instance_of Bob, Bob.new('./data/bob_elements.csv')
  end

  def test_pointless_iteration
    bob = Bob.new('./data/bob_elements.csv')

    assert_equal "S31E13", bob.final_episode
  end
end

Create a Class

require 'csv'
require 'pry'

class Bob
  def initialize(filename)
    @filename = filename
  end

  def final_episode
    episode = {}

    CSV.foreach(@filename, headers: true) do |row|
      episode["EPISODE"] = row["EPISODE"]
    end

    episode["EPISODE"]
  end
end

Run our Test

• How long does this take?
• Why?
• How can we speed it up?
• Let’s do it!

Advantages? Disadvantages?

Build Fixtures

With remaining time, review your Black Thursday project to see if it would benefit from creating fixtures.

Summary

• What is a fixture?
• How might you use a fixture in Black Thursday?