thibautbaissac/rails_ai_agents/testing-patterns

require "test_helper"
 
class CardTest < ActiveSupport::TestCase
  setup do
    @card = cards(:logo)
    @user = users(:david)
    Current.user = @user
    Current.account = @card.account
  end
 
  teardown do
    Current.reset
  end
 
  test "fixtures are valid" do
    assert @card.valid?
  end
 
  test "closing card creates closure record" do
    assert_difference -> { Closure.count }, 1 do
      @card.close(user: @user)
    end
    assert @card.closed?
    assert_equal @user, @card.closed_by
  end
 
  test "open scope excludes closed cards" do
    @card.close
    assert_not_includes Card.open, @card
    assert_includes Card.closed, @card
  end
end

require "test_helper"
 
class CardsControllerTest < ActionDispatch::IntegrationTest
  setup do
    @card = cards(:logo)
    sign_in_as users(:david)
  end
 
  test "should create card" do
    assert_difference -> { Card.count }, 1 do
      post board_cards_path(@card.board), params: {
        card: { title: "New card", column_id: @card.column_id }
      }
    end
    assert_redirected_to card_path(Card.last)
  end
 
  test "requires authentication" do
    sign_out
    get card_path(@card)
    assert_redirected_to new_session_path
  end
end

# test/test_helper.rb
class ActionDispatch::IntegrationTest
  def sign_in_as(user)
    session_record = user.identity.sessions.create!
    cookies.signed[:session_token] = session_record.token
    Current.user = user
    Current.identity = user.identity
    Current.session = session_record
  end
 
  def sign_out
    cookies.delete(:session_token)
    Current.reset
  end
end
 
class ActiveSupport::TestCase
  fixtures :all
  parallelize(workers: :number_of_processors)
end

# Record count changes
assert_difference -> { Card.count }, 1 do ... end
 
# Attribute updates
@card.close
assert @card.closed?
assert_equal @user, @card.closed_by
 
# Errors
assert_raises ActiveRecord::RecordInvalid do
  Card.create!(title: nil)
end
 
# Collections
assert_includes Card.open, @card
refute_includes Card.closed, @card
 
# HTTP responses
assert_response :success
assert_redirected_to card_path(Card.last)
 
# DOM assertions
assert_select "h1", "Cards"
assert_select ".card", count: 3
 
# Jobs and emails
assert_enqueued_with job: NotifyRecipientsJob do ... end
assert_emails 1 do ... end

# BAD: Using factories
let(:card) { FactoryBot.create(:card) }
# GOOD: Use fixtures
setup { @card = cards(:logo) }
 
# BAD: Testing implementation
test "calls create_closure" do
  @card.expects(:create_closure!)
  @card.close
end
# GOOD: Test behavior
test "closing creates closure" do
  @card.close
  assert @card.closed?
end
 
# BAD: Creating data when fixtures exist
setup { @user = User.create!(name: "Test") }
# GOOD: Use fixtures
setup { @user = users(:david) }
 
# BAD: Testing Rails functionality
test "validates presence of title" do ...
# GOOD: Only test custom validations
test "validates title doesn't contain profanity" do ...