# Testing & QA > Selected Engineer ApS work demonstrating Testing & QA — the achievements that prove it. - [Streamlined CI/CD processes, saving 4,000 hours by introducing automation in software development pipelines.](https://engineer.company/portfolio/streamlined-ci-cd-processes-saving-4-000-hours-42/) - [Migrated the HTTP API from Fiber to Huma v2 — 649 paths and 760 operations — reaching and holding 100% parity between the routes the server registers and the OpenAPI description it publishes.](https://engineer.company/portfolio/migrated-the-http-api-from-fiber-to-huma-60/) - [Generated the API contract outward from the database — OpenAPI, a 44,076‑line typed TypeScript client, 61 mock handlers and the limits the UI enforces — with a guard at every hop that fails on drift.](https://engineer.company/portfolio/built-a-request-schema-validation-contract-with-automated-61/) - [Built GitHub Actions CI/CD pipelines with a distroless production frontend image and multi‑environment promotion.](https://engineer.company/portfolio/built-github-actions-ci-cd-pipelines-with-a-69/) - [Authored 578 go‑task automation targets spanning native, Docker and HTTPS dev modes, linting, testing, database and deployment.](https://engineer.company/portfolio/authored-578-go-task-automation-targets-70/) - [Set a zero‑warnings quality bar across six languages — Go, TypeScript, SQL, Python, Shell and Markdown — enforced by pre‑commit hooks.](https://engineer.company/portfolio/set-a-zero-warnings-quality-bar-across-six-79/) - [Built a layered automated test suite — 981 Go tests, 543 frontend and browser specs, 494 SQL behavioural tests — with mutation testing, property‑based tests and an accessibility gate.](https://engineer.company/portfolio/built-a-layered-automated-test-suite-across-four-layers-94/) - [Built the repository's guard engine — 268 registered commit checks, 277 lint rules and 15 custom ESLint rules — plus 146 tests of the guards themselves, so the build holds the standard, not review.](https://engineer.company/portfolio/built-the-repository-s-guard-engine-of-268-checks-95/) - [Kept the schema honest across 1,022 migrations with a CI gate that builds the database both ways — a fresh install, and an install plus every migration — and fails when the two disagree.](https://engineer.company/portfolio/kept-the-schema-honest-across-1022-migrations-99/) - [Hardened SSH to 24 asserted directives with three‑stage validation — the candidate file, the assembled config, then the daemon's own read‑back — after the read‑back caught the running server silently overriding two of the twenty‑four.](https://engineer.company/portfolio/hardened-ssh-with-three-stage-validation-111/) - [Proved the intrusion‑banning path end to end on every hardening run by banning a reserved test address, reading the resulting kernel rule and unbanning in a guaranteed cleanup block, so a jail that stops working fails a run instead of reporting healthy.](https://engineer.company/portfolio/proved-the-intrusion-banning-path-on-every-converge-112/) - [Verified firewall rules by position rather than presence, reading the numbered rule list and the live packet‑filter chain, because a rule that exists is not a rule any packet reaches.](https://engineer.company/portfolio/verified-firewall-rules-by-position-113/) - [Made check mode tell the truth across the whole platform after finding six probes deciding on a value the host never gave, because Ansible's command module reports success under --check while skipping the command entirely.](https://engineer.company/portfolio/made-ansible-check-mode-tell-the-truth-116/) - [Added a preflight play that runs the same code as the converge against operator‑local secrets in about a second, after a half‑applied production run died on its ninth task with the swap settings already written to the live host.](https://engineer.company/portfolio/added-a-preflight-play-for-secrets-117/) - [Cut systemd sandbox exposure across every unit this platform installs — a dead‑man's‑switch service from 9.6 UNSAFE to 1.5, an internet‑facing git forge from 8.3 EXPOSED to 1.5 — and added a converge‑time parser check after finding a misspelled directive silently ignored in three unit templates.](https://engineer.company/portfolio/cut-systemd-sandbox-exposure-across-every-unit-119/) - [Built a commit gate of 22 one‑line linters plus four that earn a paragraph, with no warning tier and no inline suppressions permitted, covering HTML, CSS, JavaScript, Python, YAML, Markdown, shell, links, spelling, secrets and typography.](https://engineer.company/portfolio/built-a-22-linter-commit-gate-127/) - [Cut the site's browser‑driven quality gate from 1,636 seconds to 615 by scheduling its checks longest‑first through a worker pool bounded to four lanes, after measuring that alphabetical order cost 320 seconds against 224.](https://engineer.company/portfolio/cut-the-visual-quality-gate-to-ten-minutes-128/) - [Replaced 27 rendered font sizes whose nearest neighbours were 0.6% apart with a six‑step Major Third scale, and wrote the linter that fails the twenty‑eighth.](https://engineer.company/portfolio/replaced-27-font-sizes-with-a-six-step-scale-129/) - [Took WCAG 2.2 Level AA across 32 representative pages — one per template per language — in both colour themes, plus two AAA criteria, with a documented conformance record and a check defending each claim.](https://engineer.company/portfolio/took-wcag-2-2-level-aa-across-the-whole-site-130/) - [Found and fixed 11 accessibility defects the browser reported as healthy — eight footer links still in tab order behind pointer‑events, a scroll timeline clipping the colophon off three pages, and a rule engine running 70 of its 105 rules.](https://engineer.company/portfolio/fixed-11-accessibility-defects-the-browser-called-healthy-131/) - [Closed the colour system at 28 documented colours with a linter that fails a value painted but undocumented, documented but unpainted, mis‑measured, respelled as a literal, or within a perceptual distance of 0.02 of one already there.](https://engineer.company/portfolio/closed-the-colour-system-at-28-colours-133/) - [Found that the light theme had been missing a full‑page overlay layer since the day it was written, by asserting that both themes paint every layered surface with the same number of layers.](https://engineer.company/portfolio/found-the-light-theme-missing-an-overlay-layer-134/) - [Made reduced‑motion honest after finding eleven selectors still animating under the preference, because a universal transition‑none rule loses on specificity to any rule carrying a class.](https://engineer.company/portfolio/made-reduced-motion-honest-135/) - [Fixed a sitemap where 172 of 176 URLs shared one modification timestamp, by taking the date from git history after establishing that the export rewrites every file on every run.](https://engineer.company/portfolio/fixed-a-sitemap-with-one-shared-timestamp-140/) - [Put the documentation under its own linter — a per‑file line budget that only ratchets down, an index requirement and a real‑path check — which found six of nine plans marked done while carrying unchecked boxes, and fourteen commit‑gating tasks named in no document.](https://engineer.company/portfolio/put-the-documentation-under-its-own-linter-142/) - [Brought 10,242 lines of quality‑gate JavaScript under a formatter and a linter after establishing it was the largest body of code in the repository and the only one nothing read, fixing 13 findings and suppressing none.](https://engineer.company/portfolio/brought-the-quality-gate-code-under-a-linter-143/) - [Held the generator to 981 test cases at a 92% branch‑coverage floor with warnings treated as failures, and asserted idempotence by running the whole build pipeline twice from an empty file and requiring the second pass to change nothing.](https://engineer.company/portfolio/held-the-generator-to-964-tests-and-a-coverage-floor-145/) - [Established PDF/UA‑1 conformance across nine documents at 106 of 106 rules, and found the archival variant failing one rule of 146 — a near‑miss that reads as a pass to anyone not running the validator.](https://engineer.company/portfolio/established-pdf-ua-1-conformance-across-nine-documents-146/) - [Selected every rule the Python linter has as an error, working through 1,815 findings to reach zero, with each of the few exemptions carrying a written reason and two of them backed by a checker instead of a comment.](https://engineer.company/portfolio/enabled-every-python-linter-rule-as-an-error-147/) - [Vendored a QR encoder — Reed‑Solomon over GF(256), fixed module layout, eight mask patterns — in 522 lines rather than take a third runtime dependency, and verified it by reading the finished matrix back with an independently written decoder.](https://engineer.company/portfolio/vendored-a-qr-encoder-in-522-lines-148/) - [Wrote tests for the checkers themselves after establishing that a checker fed only clean input will one day report clean because it read nothing — planting a misspelling to confirm the spell‑check finds it, and taking an id range from the database rather than from a number in the test.](https://engineer.company/portfolio/wrote-tests-for-the-checkers-themselves-149/) - [Found the commit hooks and the quality gate running different checks while a document promised they were the same, by comparing the two lists in a test — the five that only ever ran by hand were the ones reading the CV prose.](https://engineer.company/portfolio/found-the-commit-hooks-and-the-gate-disagreeing-150/) - [Rehearsed the forge‑side CI hook and found two defects unreachable by reading the file: a fallback that put an unresolvable argument on the hook's input, and git's own environment variable following the gate into the checkout and turning 19 tests red.](https://engineer.company/portfolio/rehearsed-the-forge-side-ci-hook-151/) - [Built a cross‑language content check that fails when a translation drops a figure the English states, and when a language uses notation it does not use — finding two Danish descriptions missing a metric and sixteen Ukrainian spans quoting in the English style.](https://engineer.company/portfolio/built-a-cross-language-figure-and-notation-check-153/) - [Stopped an application filling memory at 41 MB a second — a recorded 111 GB of compressed pages on a 36 GB machine — by bounding every event stream, subscribing by event type and putting a rate budget on logging, taking 610,996 log lines down to 1,411.](https://engineer.company/portfolio/stopped-an-application-filling-memory-at-41mb-a-second-155/) - [Adopted Swift 6 complete strict concurrency with no actors, bridging a blocking C event loop to the main actor through one producer, one consumer and one ordering — after establishing that a task per event loses the ordering the interface depends on.](https://engineer.company/portfolio/adopted-swift-6-strict-concurrency-over-a-c-event-loop-156/) - [Wrote a parser that reads the real 7,308‑line C header and verifies every call site, every enum constant and that every pointer‑owning class is final, after a hand‑written placeholder header let calls to three removed functions compile, link and crash.](https://engineer.company/portfolio/wrote-a-parser-that-verifies-every-ffi-call-site-157/) - [Took the test suite from six tests over a sixty‑second limit to 135 passing in 8.9 seconds by profiling the main thread and removing the two calls it sat inside for 3,989 samples out of 4,017.](https://engineer.company/portfolio/took-the-test-suite-under-nine-seconds-158/) - [Named every icon‑only control in the interface for screen readers after finding the send button announced as "arrow up circle, button", and wrote the linter that requires the label within eight lines of the icon.](https://engineer.company/portfolio/named-all-seventeen-interface-icons-for-screen-readers-159/) - [Built a 48‑token design system on the platform's own glass material and wrote the linter that rejects a magic number, a hardcoded font size, or an animation that ignores the reduce‑motion preference.](https://engineer.company/portfolio/built-a-48-token-design-system-160/) - [Reached the half of the messaging core the application had never used — backup transfer, disappearing messages, message editing and resending, verified invitations, proxies and encryption policy — driving every test against the real library with no mocks.](https://engineer.company/portfolio/reached-the-unused-half-of-the-messaging-core-161/) - [Rewrote the application's error messages against a written tone standard after a refused sign‑in blamed the user for mistyping when the provider actually required an app‑specific password, and covered it with a test that names the provider.](https://engineer.company/portfolio/rewrote-the-error-messages-against-a-tone-standard-162/) - [Built the company's icon and favicon sets from two hand‑made drawings, with every derived asset regenerated by script and a check that fails when a derived file was committed before its source.](https://engineer.company/portfolio/built-the-visual-identity-from-two-drawings-164/)