ORIGINAL COMPANY-CONTEXT PRACTICE
Price a synthetic restaurant order deterministically
Original practice scenario: A restaurant-order simulator supports meal bundles, ingredient modifiers and location-specific prices. How should its pricing function remain testable?
Written for independent practice using company context; this is not a verified question from a company interview.
A REASONED APPROACH
Model answer.
Treat pricing as a deterministic transformation of a versioned menu and explicit order. Display names and mutable current prices should not determine historical order totals.
Work through it
- Represent items, bundles and modifiers with stable identifiers, validate allowed combinations and retain the menu version used for the quote.
- Calculate amounts using exact minor units and declared rounding rules, separating discounts, tax assumptions and fees in a transparent breakdown.
- Test repeated modifiers, unavailable items, bundle substitutions, zero quantities and price changes between quote and confirmation; require explicit requoting when necessary.
Tradeoffs to discuss
- Snapshotting prices makes receipts reproducible but requires an expiration policy for unconfirmed quotes and clear handling of menu changes.
Common pitfalls
- Do not silently substitute an item or modifier with a different price.
- The exercise's simplified tax rules should remain explicit fictional inputs.