OneshotCoverage

This gem may not be very useful when you want to use Coverage oneshot mode, however, It could be good example to study how to implement by yourself.

This gem provides simple tools to use oneshot mode easier. It gives you:

Rack middleware for logging
Pluggable logger interface

Please notice that it records code executions under the target path(usually, project base path). If you have bundle gem path under target path, It will be ignored by default.

Installation

Add this line to your application's Gemfile:

gem 'oneshot_coverage'

And then execute:

$ bundle

Or install it yourself as:

$ gem install oneshot_coverage

Usage

Configuration

OneshotCoverage.configure(
  target_path: '/base/project/path',
  logger: OneshotCoverage::Logger::NullLogger.new,
  emit_term: nil, # emit per `emit_term` seconds. It tries to emit per request when `nil`.
  cover_bundle_path: false, # record bundle gem path. Default value is false.
)
OneshotCoverage.start

As default, OneshotCoverage supports 2 logger.

OneshotCoverage::Logger::NullLogger (default)
OneshotCoverage::Logger::StdoutLogger
OneshotCoverage::Logger::FileLogger

Only required interface is #post instance method, so you could implement by yourself easily.

class FileLogger
  def initialize(log_path)
    @log_path = log_path
  end

  # new_logs: Struct.new(:path, :md5_hash, :lines)
  def post(new_logs)
    current_coverage = fetch

    new_logs.each do |new_log|
      key = "#{new_log.path}-#{new_log.md5_hash}"

      logged_lines = current_coverage.fetch(key, [])
      current_coverage[key] = logged_lines | new_log.lines
    end
    save(current_coverage)
  end

  private

  def fetch
    JSON.load(File.read(@log_path))
  rescue Errno::ENOENT
    {}
  end

  def save(data)
    File.write(@log_path, JSON.dump(data))
  end
end

Emit logs

With rack application

Please use OneshotCoverage::Middleware. This will emit logs per each request.

If you using Rails, middleware will be inserted automatically.

With job/batch application

If your job or batch are exit as soon as it finished(i.e. execute via rails runner), then you don't need to do anything. OneshotCoverage.start will set trap to emit via at_exit. On the other hand, it's not, then you need to emit it manually at proper timing(i.e. when batch finished)

Generate report with simplecov

You can generate pretty report using simplecov(confirmed with 0.21.2). Here is some example:

require 'simplecov'
require 'oneshot_coverage/simplecov_reporter'

OneshotCoverage::SimplecovReporter.new(
  project_path: Dir.pwd, # target project path. Dir.pwd is default.
  log_path: 'coverage.json', # oneshot coverage log generated by FileLogger or same scheme json file acceptable
  file_filter: OneshotCoverage::SimplecovReporter::DefaultFilter # Object respond to #call with return true | false. this filter used for coverage target. file_filter.call(path) return false, then path will not be included to report. DefaultFilter is default, which exclude non-ruby file, files under /spec/, /test/, /script/, /config/
).run

This code generates html report under <project_path>/coverage/

Note

Note that cover_bundle_path only cover managed gem by bundler. In the other words, the gem installed with path option, which bundler just load it, will not be included by this.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the OneshotCoverage project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.

riseshia/oneshot_coverage