nrml
Data integrity and testingShopifyNextdoor

Gift Exchange: Preserve People and Make Repeatable Draws

Repair CSV parsing, assign every participant exactly once, and isolate seeded draws.

The scenario

Repair CSV parsing, assign every participant exactly once, and isolate seeded draws.

A failure to reason about

Use a small data integrity and testing scenario to compare current behavior with the requirement.

Illustrative context for the topic. The exercise’s full requirements arrive in the workspace.

Questions to bring to your review

  • Which caller makes the reported behavior visible?
  • What focused regression would distinguish the current behavior from the requirement?
  • What existing behavior must remain intact after the change?

Skills you will practice

  • CSV parsing
  • Identity invariants
  • Randomized algorithms
  • Reproducible testing

Read the existing code, reproduce the reported behavior, review proposed changes, and verify your final implementation. You can use AI assistance while staying responsible for the result.

Prepare with a worked example

See how nrml evaluates an attempt, including the limits of automated evidence.