rails-testing

name	rails-testing
description	Ruby on Rails testing conventions — Minitest strategy, fixtures, system tests. Use when writing tests, setting up test data, or running test suites.

Rails Testing Skill

Testing strategy for Rails applications using Minitest and fixtures. Not RSpec, not FactoryBot.

Sub-files:

• FIXTURES.md — Fixture patterns and test data management
• SYSTEM-TESTS.md — System and integration test conventions

---

Philosophy

• Test at the model level first — Business logic lives in models; that's where tests provide the most value
• Fixtures over factories — YAML fixtures are deterministic, fast, and require no setup code
• Always set Current.session — Lambda defaults and multi-tenancy depend on it; forgetting it is the #1 test failure
• Test behavior, not implementation — Assert on outcomes, not internal method calls
• Use assert_difference for state changes — Catches false positives that boolean checks alone miss

---

File Organization

test/
  models/
    card/
      archivable_test.rb    # Concern tests get their own file
    card_test.rb
  controllers/
    cards/
      closures_controller_test.rb
  jobs/
    notify_recipients_job_test.rb
  fixtures/
    cards.yml
    sessions.yml

---

Standard Test Structure

require "test_helper"

class Card::CloseableTest < ActiveSupport::TestCase
  setup do
    Current.session = sessions(:david)  # Always — sets user + account context
  end

  test "close creates closure record and marks card closed" do
    card = cards(:logo)

    assert_difference -> { Closure.count }, +1 do
      card.close
    end

    assert card.closed?
  end
end

---

Model Testing

State Changes

Nest assert_difference blocks when multiple record types change together:

assert_difference -> { Closure.count }, +1 do
  assert_difference -> { Event.count }, +1 do
    card.close
  end
end

assert card.closed?
assert_equal "card_closed", Event.last.action

Event Attributes

Count alone is insufficient — always verify attributes:

event = Event.last
assert_equal "card_archived", event.action
assert_equal card, event.eventable
assert_equal Current.user, event.creator
# For events with particulars:
assert_equal old_board.name, event.particulars["old_board"]

Scopes

card.archive

assert_includes Card.archived, card
assert_not_includes Card.unarchived, card

---

Controller Testing

Inherit from ActionDispatch::IntegrationTest. Assert on model state after the request:

class Cards::ClosuresControllerTest < ActionDispatch::IntegrationTest
  setup do
    Current.session = sessions(:david)
    @card = cards(:logo)
  end

  test "create closes the card" do
    post card_closure_path(@card.number)
    assert @card.reload.closed?
  end
end

---

Job Testing

Test synchronous logic and async enqueuing separately:

# Business logic — fast, no job infrastructure
test "process_data updates records" do
  record.process_data
  assert record.processed?
end

# Async wrapper — verify enqueuing
test "process_data_later enqueues job" do
  assert_enqueued_with(job: ProcessDataJob, args: [record]) do
    record.process_data_later
  end
end

Multi-tenancy is automatic — Current.account is captured and restored by the job extension. Setting Current.session in setup is sufficient.

---

Common Gotchas

1. Missing Current.session — Lambda defaults (default: -> { Current.user }) raise nil errors. Put it in setup, not inline.

2. Only checking event count — After assert_difference, verify Event.last.action, eventable, and creator.

3. Skipping assert_difference — assert card.archived? can pass if the flag is set wrong. Wrap the action in assert_difference -> { Card::Archive.count }, +1 to confirm the record was created.