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Runner Class & Cucumber Options

The Runner Class is the control center for executing Cucumber tests. It tells Cucumber what to run, where to find it, and how to report results.

Understanding the runner properly prevents undefined steps, wrong executions, and CI failures.

What is a Runner Class?​

A runner class:

  • Triggers Cucumber execution
  • Connects Cucumber with TestNG or JUnit
  • Configures features, glue, tags, plugins, and dry run

Cucumber itself does not start execution — the runner does.

Runner Responsibilities​

The runner controls:

  • Feature file location
  • Step definition (glue) location
  • Tags for selective execution
  • Reporting plugins
  • Dry run behavior

Think of the runner as the execution configuration file.

Common Runner Integrations​

  • Cucumber + TestNG (most common in automation)
  • Cucumber + JUnit

Choice depends on:

  • Existing framework
  • Parallel execution needs
  • Reporting preferences

Key Cucumber Options (Conceptual)​

features​

  • Path to .feature files
  • Can point to folder or single file

Best practice:

  • Point to a folder, not individual files

glue​

  • Package(s) containing step definitions and hooks
  • Must be accurate

Incorrect glue = undefined steps.

tags​

  • Controls which scenarios run
  • Enables smoke, regression, sanity runs

Tag logic belongs in runner, not feature files.

plugin​

  • Controls reporting
  • HTML, JSON, pretty output, etc.

Plugins do not affect execution logic — only reporting.

dryRun​

  • Validates step definitions
  • Does NOT execute automation code

Used to:

  • Detect undefined steps
  • Validate glue configuration

Typical Execution Flow​

Runner Starts
   ↓
Features Located
   ↓
Glue Loaded
   ↓
Scenarios Filtered by Tags
   ↓
Steps Matched
   ↓
Execution Happens
   ↓
Reports Generated

Multiple Runners Strategy​

Large projects often use:

  • Smoke runner
  • Regression runner
  • API runner

Each runner:

  • Uses different tags
  • Same feature files

Avoid one massive runner for everything.

Common Runner Mistakes ❌​

  • Wrong feature path
  • Incorrect glue package
  • Hardcoding tags
  • Mixing JUnit and TestNG configs
  • Forgetting dry run during setup

CI/CD Awareness​

In CI:

  • Runner controls execution scope
  • Tags drive pipeline stages
  • Reports generated via plugins

Runner configuration should be environment-agnostic.

Interview-Ready Questions​

Q: What is the purpose of a runner class?
A: To configure and trigger Cucumber execution.

Q: What does dryRun do?
A: Validates step definitions without executing tests.

Key Takeaways​

  • Runner controls execution
  • CucumberOptions define behavior
  • Correct glue is critical
  • Tags enable selective runs
  • Dry run saves setup time