PHP From ZeroModern PHP course

testing php applications

Migrating Between PHPUnit And Pest

A PHPUnit-to-Pest migration is a maintenance project, not a rewrite of application behaviour. Pest can work alongside PHPUnit-style tests, which allows gradual migration when the change has a clear benefit.

Migrate Incrementally

Keep the suite green, convert a small representative slice, compare CI output, and preserve fixtures and boundary coverage. Do not combine syntax migration with broad production refactoring.

Review Tooling And Team Workflow

Check IDE integration, CI commands, coverage, plugins, test filtering, onboarding docs, and framework helpers. A migration is complete only when daily workflow remains reliable.

Start with a bounded trial:

  1. Keep the existing suite green.
  2. Install and initialise the target tooling.
  3. Convert a small representative group.
  4. Compare CI, coverage, IDE support, and local workflow.
  5. Continue only if the benefit is clear.

Common Mistakes

  • Converting every test in one change.
  • Changing production code and test syntax together.
  • Losing coverage, filtering, or IDE workflow.
  • Assuming automated conversion removes the need for review.

What To Practise

  • Plan an incremental migration.
  • Preserve suite behaviour and workflow.
  • Stop migration when cost exceeds benefit.

Practice

Practice: Plan A Small Pest Trial

Create a migration trial for one PHPUnit directory.

Requirements

  • Keep the complete suite green.
  • Select a representative directory.
  • Compare commands, CI, and coverage.
  • Define a stop condition.
Show solution

A bounded trial makes cost visible before a large commitment.

Convert tests/Unit/Pricing as the trial scope. Prove that the same scenarios pass before and after conversion, document local, CI, coverage, and IDE commands, and stop if readability or maintenance does not improve.

Review converted tests as tests, not only as syntax changes.