Testing the POC walkthrough

A step-by-step run through the entire POC. Every command is run from the repo root.

0. Prerequisites

Verify the toolchain is installed:

cargo --version   # cargo 1.93+ tested
rustc --version   # rustc 1.93+ tested
git --version
curl --version    # for the PDF download script

If any are missing, install Rust via rustup.

1. Project layout

greenbook/
  rules/                         - canonical computable sources (TOML), top-level
    schedule-uk-2026-01-01.toml      - the current UK schedule
    product-map-uk-snomed-dm.toml    - SNOMED UK drug extension product → antigens map
  conformance/                   - shared test harness (fixtures, cases.json, expected/)
  rust/                          - the reference implementation
    src/                         - lib (evaluate.rs, fhir.rs, schedule.rs, products.rs, age.rs)
    src/bin/greenbook.rs         - CLI; src/bin/conformance.rs - golden generator
    tests/                       - integration + conformance tests
  js/                            - the JavaScript implementation (greenbook.js + test/)
  docs/                          - presentation + demo (this walkthrough)
  spec/                          - the specification documents (incl. roadmap)
  s/, pdf/                       - helper scripts; downloaded source PDFs (gitignored)

This walkthrough drives the Rust implementation; commands run from the repo root with --manifest-path rust/Cargo.toml.

2. Fetch the source Green Book PDF (optional)

The schedule TOML is the source of truth for the evaluator, but if you want the original PDF on disk for reference:

s/download-green-book.sh

It is idempotent — re-runs skip files already present. Pass --force to re-download.

3. Build the crate

cargo build --manifest-path rust/Cargo.toml
cargo clippy --manifest-path rust/Cargo.toml --all-targets -- -D warnings

First build pulls dependencies (chrono, serde, toml, serde_json, clap, thiserror) from crates.io and takes ~5s on a warm machine. Subsequent builds are incremental.

4. Run the test suite

cargo test --manifest-path rust/Cargo.toml

You get the unit tests in rust/src/age.rs (AgeOffset parsing and date arithmetic), the integration tests in rust/tests/evaluate.rs, and the conformance test in rust/tests/conformance.rs (which checks the engine reproduces every golden in conformance/expected/). The integration tests pin the evaluation date to 2026-04-29 so results are deterministic.

5. Run the CLI on the bundled fixture

The fixture represents a 6-month-old female, DOB 2025-10-29, who has received every immunisation due so far at her 8-week, 12-week and 16-week visits, all from the latest Green Book products.

Human-readable report:

cargo run --manifest-path rust/Cargo.toml --quiet --bin greenbook -- \
  evaluate \
  rules/schedule-uk-2026-01-01.toml \
  rules/product-map-uk-snomed-dm.toml \
  conformance/fixtures/six-month-fully-vaccinated.json \
  --evaluated-at 2026-04-29

JSON output:

cargo run --manifest-path rust/Cargo.toml --quiet --bin greenbook -- \
  evaluate \
  rules/schedule-uk-2026-01-01.toml \
  rules/product-map-uk-snomed-dm.toml \
  conformance/fixtures/six-month-fully-vaccinated.json \
  --evaluated-at 2026-04-29 \
  --format json

If you omit --evaluated-at it defaults to today; the same fixture will give different results once you cross the next due-date boundary.

6. What you should see

The README Walkthrough is the canonical, annotated tour of the output across several demonstration fixtures. In brief, for this on-schedule infant the salient lines are:

• Up-to-date status: UP_TO_DATE_FOR_AGE — the headline, age-relative answer: every dose due so far has been given. Distinct from Fully vaccinated: no, the strict "every dose at every age" flag, which is correctly no for a 6-month-old.
• [COMPLETE ] 6-in-1 (3/3 due, 3 total) - up to date — three valid doses, all on or after earliest_age.
• [PARTIAL ] MenB (2/2 due, 3 total) - up to date — dose 3 isn't due until 12 months, so the patient is still up to date despite the series being incomplete.
• [NONE ] MMR (first dose) (0/0 due, 1 total) - up to date — nothing due yet.

The booster series (Hib/MenC, Td/IPV) show no doses and no spurious OUT-OF-SCHEDULE entries: conformance matches doses to series by product class, so a 6-in-1 dose is never dragged into a booster series via shared antigens. See conformance vs coverage for the conformance-vs-coverage decision behind this.

7. Try changing the inputs

Quick experiments to confirm the engine is doing real work, not pattern matching. The other bundled fixtures (behind-for-age-toddler.json, out-of-schedule-doses.json, unmatched-doses.json) already show these effects; you can also edit six-month-fully-vaccinated.json yourself:

8. Inspecting the schedule itself

Open rules/schedule-uk-2026-01-01.toml directly. Every series is one [[series]] block with its doses inline; antigen IDs at the bottom map to SNOMED concept codes. Historical slices use the same structure: inspect them with cargo run --manifest-path rust/Cargo.toml --quiet --bin greenbook -- versions rules --country UK.

9. Next steps

The design questions the POC raised are resolved and folded into the spec and roadmap. The current-schedule correctness work is implemented and covered by the shared conformance suite, including dose-sequence flags and duplicate echo detection. Historical versioning has started: evaluate-auto selects schedule versions by dose due date, and the first curated Green Book slices are in rules/.