Testing

One rule above the others: a gate that did not judge may not say PASS. Every required test's inputs are committed to this repository or built by the run itself. No required test skips, reads an ATLAS_* variable, or looks in the home directory. CI enforces the first half of that structurally: Go tests run through tools/testgate, which fails the run if any test skipped, whatever the exit code said.

History, where it is needed, is a pointer rather than a chapter: the pre-rewrite tree and its capture programs are archived on the golden-reference tag (mirrored at archive/golden-reference), and the behavioral differences accepted against it are decision 18.

The layers

make test is the whole required surface, and what CI runs on ubuntu, macOS and Windows (spelled step by step in .github/workflows/ci.yml, because the Windows runner has no make):

• go vet ./..., then go run ./tools/testgate ./... — every Go test in the module, skip-proof, with -race on the platform where a C toolchain is free.
• npm run lane and npm run seam-lane — each TypeScript lane's boundary rules, tsc --strict, and its own suite.
• go run ./tools/depcheck — the import matrix, hostenv purity, network confinement, semconv discipline.

make test-e2e is the application in a real browser. The run builds every one of its own prerequisites: the seam (make static), a registry packed from the committed corpus (tests/e2e/prep), and the server Playwright starts itself. The specs assert arrangement — URLs, the state island, the topbar's controls, session memory — never pixels.

make corpus-smoke is the maintainer's deep check and deliberately not a CI gate: it walks a real installed library (-bundles, else $ATLAS_BUNDLES_DIR, else the application's data directory) and holds every current-format bundle to the reader's invariants. It compares no stamps, no hashes and no content.

make release-packaging is the hermetic half of native distribution acceptance. It parses the macOS property list and Linux shared-MIME XML, checks the Windows installer association, and holds the workflow to draft-first, exact-asset publication. The platform jobs perform the dynamic half: Windows installs its package and reads the registered open command, Linux installs its .deb and checks MIME registration, and macOS unpacks and verifies its app seal and UTI. All three packaged executables must intake the exact same freshly built Sample Region .atlas into isolated libraries. The release job also inspects payloads and builds Sample Region online and offline through the packaged CLI. Byte inequality is a release failure.

What tests are made of

Stated bundles. The default. A test that needs a bundle writes one through format/bundle's real writer from a few lines of Go (see format/bundle/fixture_test.go, internal/workbench/bundles_test.go) — nothing opaque is committed, and a bundle a test measures is a bundle the application could open.

The corpus (testdata/corpus/). Real extractions, kept because their provenance is public: bend-or is city open data, mars is NASA Trek. They give the format, render, island and e2e suites real bytes with real depth — multipart zones, described shapes, a sphere with two lenses — at the price of about 14 MB. Public provenance is the bar for adding anything here; see its README.

Hand-derived vectors (analysis/testdata/cells/). The cell-system contract, written down rather than recorded, and read by both implementations of the arithmetic: the TypeScript lane's conformance suite and the Go twin's (tests/cells). Until the planned unification deletes one copy, these vectors are what keep the two from drifting.

Property tests for what no single example can pin down: containment, hierarchy, carry and plan-order invariants over invented locations in the analysis lane; determinism in the pipeline (build twice, byte-identical); fuzzing where bytes cross a trust boundary (format/bundle's reader).

Where tests live

Tests live with their package. Two trees exist because some tests cannot:

• tests/ — Go tests that need os against packages that may not (hostenv forbids internal/app the filesystem): tests/island drives the application's routes over the corpus, tests/cells reads the shared vectors, tests/e2e is the browser suite, tests/corpus the shared packer.
• tools/ — the enforcement commands: depcheck, testgate, corpussmoke.

The bar for a new test

Ask one question: what breaks if this test is deleted? A test that anchors a number nobody can recompute, reads a path only one machine has, or skips when the world is not to its liking does not clear it. State the bundle, derive the expectation by hand, and if the inputs cannot be committed, the check belongs behind make corpus-smoke — named as a maintainer's check, not dressed as a gate.