Making reports and charts agree — Isla Smyth
← All workSustainability reporting · 2026

Making reports and charts agree

SQL reporting improvements and integration checks comparing exported emissions, chart totals and known expected values.

  • PostgreSQL
  • TypeScript
  • Integration tests

The context

A sustainability platform presented related emissions data through charts and exported reports. These different paths needed to produce consistent totals across dates and emission factors.

What I worked on

  • Refactored a reporting query to join pre-resolved conversion-rate identifiers from a daily aggregate.
  • Added integration tests comparing exported totals with seeded expected values and chart responses.
  • Covered per-factor totals and date scenarios using an explicit numerical tolerance.

Lessons learned

A report can look plausible while being wrong. Comparing multiple outputs with known data provides a more useful check than verifying only that a file was generated.