27. Integration tests run the referees in containers

Date: 2026-09-13

Status

Accepted

Context

The corpus promises that our claims are checked by tools we did not write. Running them in containers makes that reproducible: the same versions answer on a laptop and in CI, and nobody installs anything. It also removes the last "please install this on the runner" from the build.

Decision

tests/AdCodicem.Pdf.IntegrationTests uses Testcontainers to run qpdf — and later veraPDF, pdftotext, mutool — against the corpus.

Consequences

• Consequence — where no Docker daemon exists the tests skip with the reason attached, visible in the run. CI has Docker, so skipping there would be a failure of the runner, not of the suite.

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Recorded as D26 before this project adopted Architecture Decision Records; the identifier still appears in commit messages and in CLAUDE.md.