Testing Rails applications

Use the application profile for a full Rails application or for a Lesli workspace that loads several engines and gems into one test process.

Test helper

A conventional test/test_helper.rb is:

ENV["RAILS_ENV"] ||= "test"

require_relative "../config/environment"
require "rails/test_help"
require "lesli_testing"

LesliTesting.app(
  "LesliBuilder",
  coverage_min_coverage: 90
)

module ActiveSupport
  class TestCase
    parallelize(workers: :number_of_processors)
  end
end

Loading rails/test_help first makes the LesliTesting Rails base classes available. Keep the configuration before any explicit require calls that load application components solely for the test suite.

Application coverage profile

The application profile starts with SimpleCov's Rails defaults and tracks Ruby files under:

app/
lib/
engines/
gems/

This profile is useful in a monorepo because source files from locally installed engines and gems can be included in the same report.

Example model test

Use the standard Rails base class or the LesliTesting model base class:

require "test_helper"

class AccountTest < LesliTesting::ModelTester
  test "is inactive after its expiration time" do
    account = accounts(:expired)

    travel_to account.expires_at + 1.minute do
      refute account.active?
    end
  end
end

LesliTesting::ModelTester includes ActiveSupport::Testing::TimeHelpers.

Example integration test

require "test_helper"

class AccountsControllerTest < LesliTesting::IntegrationTester
  test "returns the accounts collection" do
    get accounts_url, as: :json

    expect_response_with_successful
    assert_kind_of Array, response_json
  end
end

See Testing tools for the response helpers and fixture behavior.

Run application tests

bin/rails test
bin/rails test test/models/account_test.rb
COVERAGE=true bin/rails test
QUIET=true COVERAGE=true bin/rails test

Coverage output is written under coverage/ in the directory where the test process runs.