minitest-heat - GitLite

KO | EN

gitlite — search

#hacktoberfest #react #go #machine-learning #rust #deep-learning #docker #java #windows #cli #vue #awesome-list #pytorch #openai

minitest-heat

(★ 57)

A custom reporter for Minitest to help you more effectively fix code when tests fail.

File Explorer

Download Latest Version (.zip)

- - main.yml
  - release.yml
- FUNDING.yml
- console
- setup
- - heat.rb
  - heat_plugin.rb
  - heat_reporter.rb
- - source.rb
- - contrived_code.rb
  - contrived_examples_test.rb
  - contrived_heat_map_test.rb
  - contrived_issue.rb
  - contrived_locations.rb
  - contrived_setup_failures_test.rb
  - contrived_skips_and_slows_test.rb
  - heat_reporter_test.rb
  - heat_test.rb
- - issue_helpers.rb
- .rubocop.yml
- test_helper.rb
.flayignore
.gitignore
.reek.yml
.reviewer.yml
.reviewer_history.yml
.rubocop.yml
CHANGELOG.md
CODE_OF_CONDUCT.md
favicon.svg
Gemfile
Gemfile.lock
LICENSE.txt
minitest-heat.gemspec
Rakefile
README.md
RELEASING.md

// repository documentation

Was this content helpful?

★ 0 (0 ratings)

# 🔥 Minitest Heat 🔥
Minitest Heat helps you identify problems faster so you can more efficiently resolve test failures by generating a heat map that shows where failures are concentrated.

For a more detailed explanation of Minitest Heat with screenshots, [head over to the wiki for the full story](https://github.com/garrettdimon/minitest-heat/wiki).

Or for some additional insight about priorities and how it works, this [Twitter thread](https://twitter.com/garrettdimon/status/1432703746526560266) is a good read.

## Installation
Add this line to your application's Gemfile:

```ruby
gem 'minitest-heat'
```

And then execute:

$ bundle install

Or install it yourself as:

$ gem install minitest-heat

And depending on your usage, you may need to require Minitest Heat in your test suite:

```ruby
require 'minitest/heat'
```

## Prioritizing Your Work

Minitest Heat surfaces the most impactful problems first so you can fix what matters without scrolling through noise.

### Issue Priority

Issues are displayed in priority order—you'll always see the most critical problems first:

| Priority | Type | Why First |
|----------|------|-----------|
| 1 | **Errors** | Exceptions in source code—your app is broken |
| 2 | **Broken** | Exceptions in test files—fix your tests before trusting them |
| 3 | **Failures** | Assertion failures—the core of what tests catch |
| 4 | **Skipped** | Only shown when no errors/failures—a reminder, not urgent |
| 5 | **Slow/Painful** | Only shown when everything passes—performance cleanup |

You never see skips or slow tests when there are real problems. This keeps you focused on what actually needs fixing.

### The Heat Map

After listing individual issues, the heat map shows where problems are concentrated across your codebase:

- **Files sorted by severity**—most problematic files appear first
- **Line numbers with issue counts**—`42×3` means 3 issues at line 42
- **Quick hot spot identification**—if one file keeps appearing, that's where to focus

The heat map helps you spot patterns. A single file with many issues often points to a deeper problem worth investigating rather than fixing issues one by one.

## Configuration

Minitest Heat provides configurable thresholds for identifying slow tests. By default, tests over 1.0s are considered "slow" and tests over 3.0s are "painfully slow."

Add a configuration block to your `test_helper.rb` after `require 'minitest/heat'`:

```ruby
Minitest::Heat.configure do |config|
  config.slow_threshold = 1.0        # seconds
  config.painfully_slow_threshold = 3.0
end
```

### Inherently Slow Paths

System tests, integration tests, and other browser-driven tests are inherently slower than unit tests. Rather than raising your global thresholds to accommodate them, you can tell Minitest Heat which paths to exclude from slow test reporting. Tests in those directories still run and report errors and failures normally—they just aren't evaluated against the timing thresholds.

```ruby
Minitest::Heat.configure do |config|
  config.inherently_slow_paths = ['test/system', 'test/integration']
end
```

Any test whose file path starts with a listed prefix is excluded. Common paths to consider:

- `test/system` — Rails system tests (browser-driven)
- `test/integration` — Integration tests with broader scope
- `test/e2e` — End-to-end tests

### Example: Gem Development

For a gem with fast unit tests, stricter thresholds catch performance regressions early:

```ruby
Minitest::Heat.configure do |config|
  config.slow_threshold = 0.1
  config.painfully_slow_threshold = 0.5
end
```

## JSON Output

For CI integration, tooling, or programmatic consumption, Minitest Heat can output results as JSON:

```bash
bundle exec rake test TESTOPTS="--heat-json"
```

The JSON output includes:
- **statistics** - counts by issue type (errors, failures, skipped, slow, etc.)
- **timing** - total time, tests/second, assertions/second
- **heat_map** - files with issues, sorted by severity weight
- **issues** - detailed issue data with locations and messages

Example usage:
```bash
# Capture JSON output (stderr has progress, stdout has JSON)
bundle exec rake test TESTOPTS="--heat-json" 2>/dev/null > results.json
```

## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `bundle exec rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run `bundle exec rake install`. For release instructions, see [RELEASING.md](RELEASING.md).

### Running Tests

```bash
# Run full test suite
bundle exec rake test

# Run a single test file
bundle exec rake test TEST=test/minitest/heat/issue_test.rb

# Run a single test method
bundle exec rake test TEST=test/minitest/heat/issue_test.rb TESTOPTS="-n /test_error_issue/"
```

### Forcing Test Failures
In order to easily see how Minitest Heat handles different combinations of different types of failures, the following environment variables can be used to force failures.

```bash
IMPLODE=true           # Every possible type of failure, skip, and slow is generated
FORCE_EXCEPTIONS=true  # Only exception-triggered failures
FORCE_FAILURES=true    # Only standard assertion failures
FORCE_SKIPS=true       # No errors, just the skipped tests
FORCE_SLOWS=true       # No errors or skipped tests, just slow tests
```

So to see the full context of a test suite, `IMPLODE=true bundle exec rake` will work its magic.

## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/garrettdimon/minitest-heat. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [code of conduct](https://github.com/[USERNAME]/minitest-heat/blob/master/CODE_OF_CONDUCT.md).

## License

The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).

## Code of Conduct
Everyone interacting in the Minitest::Heat project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the [code of conduct](https://github.com/[USERNAME]/minitest-heat/blob/master/CODE_OF_CONDUCT.md).