L04.md

id	course-da-visualization-l04
type	course
title	Challenge 04: Numbers match the charts
summary	summary.json is checked against ground truth; a chart disagreeing with the JSON is a failed chart.
lang	en-US
content_version	1
status	reviewed
reviewed_on	2026-09-12
hints	title body What this checkpoint tests Both suites: `summary.json` against ground truth — East 12334.94, North 14294.7, South 11200.48, grand 37830.12, 45 days. title body JSON is the audit layer A chart showing numbers that differ from the JSON is a failed chart — if the PNG and JSON disagree, the JSON loses the argument only when the PNG is right, which it almost never is. title body When you are done Every figure in `summary.json` matches the dataset's truth and you can trace each to its aggregation.

Challenge 04: Numbers match the charts

Gate: objective — both suites · Points: 10

The suite verifies summary.json against the dataset's ground truth (East 12334.94, North 14294.7, South 11200.48, grand total 37830.12, 45 days). A chart that shows different numbers than the JSON is a failed chart — the JSON is the auditable layer.

python verify.py starter --expect-failure must now exit nonzero; python verify.py solution must be green.

Checkpoint: both gates pass. Objective claim code via python verify.py.