LesliTesting provides the shared test configuration used across the Lesli Framework.

It standardizes Minitest output, SimpleCov profiles, coverage reports, and fixture loading for Rails applications, engines, and Ruby gems.

• Coverage profiles for Rails applications, Rails engines, and Ruby gems
• A human-friendly Minitest reporter with per-test timing and failure details
• SimpleCov console and Cobertura reports
• Configurable minimum coverage thresholds
• Shared base classes for integration, model, and view tests
• Automatic engine, shared Lesli fixture, and migration paths

Add LesliTesting to the test group:

bundle add lesli_testing --group test

Require the gem from test/test_helper.rb and select exactly one profile for the project. Configure LesliTesting before loading Rails or the library under test.

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

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

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

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

require "lesli_testing"
LesliTesting.engine("LesliShield", coverage_min_coverage: 90)

require_relative "dummy/config/environment"
require "rails/test_help"

$LOAD_PATH.unshift File.expand_path("../lib", __dir__)

require "lesli_testing"
LesliTesting.gem("Termline", coverage_min_coverage: 90)

require "minitest/autorun"
require "termline"

Engine suites that use the shared Rails test classes should run through bundle exec rails test or bundle exec rake app:test.

Rails engines should keep a complete generated dummy application and verify eager loading locally before pushing:

CI=true bundle exec rails test

LesliTesting does not provide an engine's runtime dependencies. Declare dependencies such as lesli explicitly in the engine gemspec and Gemfile so local and CI dependency resolution match.

For Rails applications and engines, Lesli is always included as the shared testing base. Engine profiles use the configured engine name to discover its Engine class after the dummy application boots and register the target and Lesli fixture and migration paths. Migration paths are modified only in the test environment. Pure Ruby gems remain independent from Rails and Lesli integrations.

LesliTesting initializes in five phases:

1. require "lesli_testing" reads COVERAGE and starts native Ruby line coverage immediately when enabled.
2. LesliTesting.app, .engine, or .gem selects the profile, attaches SimpleCov, and registers the Minitest reporter.
3. Rails applications and engines boot their environment. ActiveSupport load hooks install fixtures and shared test classes; the engine Railtie registers migration paths only in the test environment.
4. rails/test_help or minitest/autorun loads Minitest and the test files. LesliTesting replaces any previously registered reporter when Minitest starts.
5. At process exit, Minitest sets the suite result and SimpleCov writes coverage/coverage.xml and enforces the coverage threshold.

Loading the application, engine, or gem before steps 1 and 2 prevents coverage from observing code that Ruby already evaluated.

Run the suite normally or enable coverage with COVERAGE=true (1 and yes are also accepted):

bin/rails test
COVERAGE=true bin/rails test

bundle exec rake
COVERAGE=true bundle exec rake

Set QUIET=true (1 and yes are also accepted) to hide individual test lines while retaining the summary and failure details. Values such as false, 0, and no leave the option disabled.

Values are case-insensitive and surrounding whitespace is ignored. Every other value, including false, 0, and no, is disabled.

Dependency installation, Ruby boot, signals, and operating-system failures may return other non-zero codes. QUIET changes output only and never changes the process result.

• Installation and configuration
• Load order, environment, and exit codes
• Testing Rails applications
• Testing Rails engines
• Testing Ruby gems
• Reporter, coverage, fixtures, and test helpers
• Recommended project and gem structure

Clone the repository and install its dependencies:

git clone https://github.com/LesliTech/LesliTesting.git
cd LesliTesting
bundle install

To use local source from a Lesli development workspace, reference it from the host application's Gemfile:

gem "lesli_testing", path: "gems/LesliTesting"

Run the default test task from the LesliTesting directory:

bundle exec rake
COVERAGE=true bundle exec rake test
bundle exec rake build

The LesliTesting repository enforces a 45% coverage baseline. Rails integration behavior is tested in isolated Ruby processes, so those executed lines are not merged into the parent process report. Consumer projects keep the public 90% default unless they configure another threshold.

Run the intentional reporter failures manually when visually inspecting its output:

bundle exec ruby examples/reporter_demo.rb

The demo command is expected to fail and is intended for visually checking failure formatting.

Run the optional reporter benchmark separately from the test suite. It renders 5,000 results by default:

bundle exec ruby benchmark/reporter_benchmark.rb
ITERATIONS=10000 bundle exec ruby benchmark/reporter_benchmark.rb

• Lesli website
• Documentation
• Release notes
• Issue tracker
• Source code

• X: @LesliTech
• hello@lesli.tech
• https://www.lesli.tech

Copyright (c) 2026, Lesli Technologies, S. A.

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

The complete license text is available in the license file.

The Open-Source SaaS Development Framework for Ruby on Rails.