RSpec

To use Captain with RSpec, you need to configure your test suite to output test results to a file and then tell Captain where to find those test results.

Getting Started

RSpec can output test results to a file using the --format and --out flags. Configure Captain by creating a .captain/config.yml file in the root directory of your repository:

test-suites:
  your-project-rspec:
    command: bundle exec rspec --format json --out tmp/rspec.json --format progress
    results:
      path: tmp/rspec.json

You can change your-project-rspec to any name you like, but we typically recommend using the name of your project followed by a dash followed by rspec. The command is the command you already use to run your test suite. Captain will invoke this command to run your tests. The example above shows what you might use if you use bundle exec rspec and want to store test results in tmp/rspec.json.

Once Captain is configured, you can run captain run your-project-rspec --print-summary. If you see your typical test output followed by a captain block like this:

--------------------------------------------------------------------------------
----------------------------------- Captain ------------------------------------
--------------------------------------------------------------------------------

then you've configured everything correctly! You can now supercharge your test framework's capabilities. See below for configuring each of Captain's features.

Identifying Tests

Captain uses framework specific "identity recipes" to identify the tests in your suite. These recipes are order dependent components extracted from native test framework output.

We use this identity to track the executions of a test over the course of their lifetime in your suite. This enables us to do things like flake detection, quarantining, and retries.

For RSpec, Captain constructs the identity by parsing out the file and description attributes.

Quarantining Tests

Captain makes managing flaky tests easier than ever. When a test is identified as flaky, you can quarantine the test without modifying it, so that if only those tests fail, Captain reports a success with a 0 exit code. Unlike skipped tests, quarantined tests will continue to run, so you can still view their failure messages and see how frequently they are failing.

You can quarantine tests in OSS mode with captain add quarantine like so:

captain add quarantine your-project-rspec \
  --file ./spec/example_spec.rb \
  --description "Example is true"

See the OSS quarantining guide for more information on managing quarantined tests in OSS mode.

Retrying Tests

You can configure Captain to automatically retry failed tests to help you determine if failing tests are flaky or are genuinely failing. To configure retries, update your .captain/config.yml file like so:

test-suites:
  your-project-rspec:
    command: bundle exec rspec --format json --out tmp/rspec.json --format progress
    results:
      path: tmp/rspec.json
    output:
      print-summary: true
    retries:
      attempts: 2
      command: bundle exec rspec --format json --out tmp/rspec.json --format progress {{ tests }}

Once configured, Captain will invoke your original test command, check for any failures, and retry your tests however many times you've specified (in this example, two additional times) by templating the failures into the command specified by retries.command. The output.print-summary option is not required, but we've added it for convenience in understanding the overall results after the retries have been factored in.

Partitioning

Captain can optimally partition your test suite's files into multiple groups for execution on multiple CI nodes. Captain tracks your test file runtime so that it can balance each partition.

Configure partitioning in .captain/config.yml:

test-suites:
  your-project-rspec:
    command: bundle exec rspec --format json --out tmp/rspec.json --format progress
    results:
      path: tmp/rspec.json
    output:
      print-summary: true
    partition:
      command: bundle exec rspec --format json --out tmp/rspec.json --format progress {{ testFiles }}
      globs:
        - spec/**/*_spec.rb

Captain will fill in the testFiles placeholder of your partition.command with the files resulting from expanding your configured partition.globs.

Then partition across your CI provider's parallel jobs:

# .rwx/ci.yml

tasks:
  - key: code
    call: git/clone 2.0.7

  - key: ruby
    call: ruby/install 1.2.30
    with:
      ruby-version: 3.3.0

  - key: deps
    use: [code, ruby]
    run: bundle install

  - key: captain
    call: rwx/install-captain 1.1.6

  - key: rspec
    use: [deps, captain]
    parallel: 8
    run: captain run your-project-rspec

Usage with ABQ

Captain works with ABQ to support parallel test distribution while respecting the quarantine status of any tests. To use Captain with ABQ, the Captain CLI will wrap ABQ and ABQ will wrap your test suite. For example:

test-suites:
  your-project-rspec:
    command: bash -c "abq test --worker $ABQ_WORKER --reporter rwx-v1-json=tmp/abq.json -- bundle exec rspec"
    results:
      path: tmp/abq.json

ABQ_WORKER=0 captain run your-project-rspec

Usage with One-Liner RSpec Expectations

If you use the RSpec one-liner syntax like:

  it { is_expected.to eq(something.id) }

then your tests may not work well with Captain. Captain identifies tests based on their test descriptions. Since tests with the one-liner syntax do not have explicit test description, RSpec automatically infers a test description for the test. Unfortunately, the inferred test description includes the values of variables, which can lead to the inferred test description being non-deterministic. For example, in the case above, the inferred description may be is expected to eq "2172925c-cb2e-4338-bbd5-7aca9127fdb4" where the UUID changes every time the test is run (because something.id changes every time the test is run). As a result, features like retries and quarantining will not work with this test.

To resolve this issue, you can monkey-patch the generated description that RSpec uses to instead use an identifier based on the source code for the test. Install the method_source gem and then add the following at the end of your spec_helper.rb file after any RSpec.configure blocks.

# For tests that don't have a description, we assign them a deterministic description based on their source code
# Captain needs this to be able to correctly distinguish between tests that do not have descriptions
module RSpecGenerateDescriptionMonkeyPatch
  def generate_description
    "no description #{Digest::SHA1.hexdigest(metadata[:block].source.strip)}"
  end
end
RSpec::Core::Example.prepend(RSpecGenerateDescriptionMonkeyPatch)

With this in place, the previous example will generate a deterministic description that will work correctly with all of Captain's features.