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Latest Agents Pattern-Match Your Test Smells

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Practice TDD with a curated set of real-world katas, each with clear requirements and test cases.

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Guides & References

Learn best practices, naming conventions, and advanced TDD techniques from industry experts.

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Interactive Learning

Discover the TDD Gears model and learn how to apply TDD principles in real-world scenarios.

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Why TDD Matters More in the AI Era

The bar for "good tests" just moved. Agents made it non-optional.

  • Smells were always sampled. Humans pattern-matched their team's existing tests when writing new ones. The propagation rate was capped by typing speed, which capped the damage.
  • The cap just came off. Agents do not pattern-match slower than they generate. A team whose suite carries leaky-mock smell now produces leaky-mock tests at agent throughput.
  • Reviewers are still skimming for line-by-line issues. Smells now arrive in batches at suite-level granularity. The review surface that catches them is the one most teams have not built yet.
  • Builders make the smell-free version shorter. Eager mocking dies when the test composes a real domain object. Mystery setup dies when the world is already named. The defense is structural, not aspirational.

Read the argument: Agents Pattern-Match Your Test Smells

The Bar Moved

Old bar

Tests exist and pass. Good enough for humans with context.

New bar

Scenario names · builders · domain types · ubiquitous language. The test suite is the interface agents operate against.

Rich TDD isn't a style preference anymore. It's infrastructure for compressed-role, AI-augmented teams.

TDD Gears

Shift gears based on context, not habit

TDD Gears model showing Low, Medium, High, and Reverse gears for test-driven development

Low Gear

New territory. Build context. Small steps. Learn the shape of the problem before solving it.

Medium Gear

Patterns emerge. Apply design principles. Let the tests guide you toward better abstractions.

High Gear

Known patterns. Follow existing architecture. Move fast because the structure is already proven.

Reverse Gear

Wrong direction. Back up. Delete the test. Try a different approach. This isn't failure — it's steering.

Learn More About TDD Gears