Legacy debugging set: seven warehouse helpers, one bug each

Context

This set follows the debugging section candidates reported in Amazon's online assessment from about 2019 to 2023: seven short functions, each meant to do what its docstring says, each with exactly one bug. That section used C, C++ or Java; this set is in Python. Recent Amazon assessments use a different format, so treat this as practice for the skill: finding a fault fast against a written spec.

Each item is graded on its own, so every one you fix counts. The bug is in the function's code, never in its docstring; the fix is usually a line or two.

Items

Item	File	Function
Q1	warehouse/restock.py	restock_needed
Q2	warehouse/weights.py	total_weight
Q3	warehouse/picking.py	pick_order
Q4	warehouse/boxes.py	boxes_needed
Q5	warehouse/batches.py	oldest_batch
Q6	warehouse/late.py	count_late
Q7	warehouse/search.py	find_sku

Notes

• Run pytest tests/visible. Seven tests fail on the current code, one per item.
• Practice set modelled on candidate reports of the debugging section in Amazon's earlier online assessment. Original StackYard code, not the actual questions; not affiliated with Amazon.