Proof

Every rule, and the tests that guard it.

Each rule Ninety applies is checked three ways: an engine unit or property test, a scenario that the European Commission's own calculator also runs, and a TestSprite end-to-end test in a cloud browser on every pull request.

All 54 TestSprite tests passed on their latest cloud run (github-pr-70).

Generated 2026-10-25 01:42 UTC from src/data/rules.json and TestSprite's latest results (npm run proof:matrix). 12 rules · 40/40 of the TestSprite tests tied to a rule passed on their latest cloud run · whole suite: 54/54 passed (github-pr-70). History of every run: LOOP.md.

As of PR #70, merged 2026-10-25 as d787b01. Every number links to where it comes from.

TestSprite N/N gate

A required check reads the real count from the TestSprite V3 status and the backend run on the same commit. It fails unless both are N/N with N > 0, and fails closed when a result is missing or unreadable. How it works and what we found.

Defect ledger

All 14 pull requests that went red on TestSprite, then green, with the red and green status for each commit: 6 with app defects (7 real bugs), 1 UX, 7 test plan or CI. docs/DEFECTS.md.

Deep parity 399/400: the one difference

Two overlapping trips, 1 Jan–5 Apr and 25 Mar–10 Apr 2024, checked on 10 Apr. The Commission script prints one overstay per row: 31 Mar–5 Apr (6 days) and 31 Mar–10 Apr (11 days). The 6 days sit inside the 11. Ninety lists the 11 days once, and the script itself prints one 11-day overstay when the same days are entered as one stay. Details.

Rule	Engine tests	Commission parity	TestSprite
R1 At most 90 days in any rolling 180-day period Regulation (EU) 2016/399 (Schengen Borders Code), Art. 6(1) Regulation (EU) 2016/399, Art. 6(1) “no more than 90 days in any 180-day period, which entails considering the 180-day period preceding each day of stay”	treats the 90th day as legal and the 91st as an overstay days used equals a brute-force count of distinct days in the 180-day window	Exactly 90 days Day 91 (overstay) Manual example: last legal day, 29 Aug 2024	TS01TS03
R2 The entry day and the exit day both count Commission user manual for the short-stay calculator Regulation (EU) 2016/399, Art. 6(2) “the date of entry shall be considered as the first day of stay ... and the date of exit shall be considered as the last day of stay”	counts both the entry day and the exit day	Same-day stay Day after the spring clock change	TS03TC010
R3 A same-day exit and re-entry counts that day once Commission calculator behaviour	counts a same-day exit and re-entry once	Same-day exit and re-entry	TS26
R4 The 180-day window rolls: old days drop out Regulation (EU) 2016/399 (Schengen Borders Code), Art. 6(1) Regulation (EU) 2016/399, Art. 6(1) “no more than 90 days in any 180-day period, which entails considering the 180-day period preceding each day of stay”	drops a presence day on the 180th day before the control date and keeps the 179th allows 90 days again once the earlier stay has fallen out of the window a leap-day stay leaves the window exactly 180 days later	Re-entry after a full 90 days Manual example: 14 Jun 2024	TS34TS42TS60
R5 An overstay is named with its exact days and window Commission calculator, control mode	describes a longer overstay the way the calculator does an overstay is reported exactly when a day of stay has more than 90 days in its window	Overstay through 15 Apr Entry refused the next day	TS27TS46TS52
R6 A stay still in progress counts through today, with a latest legal exit Commission calculator, planning mode	closes an open trip on the reference day and does not extend it into a later plan	Not a calculator feature	TS28TS09
R7 A planned trip fits only up to its latest legal exit Commission calculator, planning mode	accepts a planned exit on the latest legal day and rejects the day after staying until the latest legal exit is legal, and one day more is not	Manual example: entry on 19 Jun 2024 Manual example: entry on 7 Aug 2024	TS06TS10TS35TS45
R8 Dates are YYYY-MM-DD; reversed or missing dates are refused Input rule	rejects impossible dates rejects a planned exit before entry say the date does not exist rather than that it is missing	Not a calculator feature	TS04TC009TS29TS21TS54TS61
R9 EES: a gap is explained (missing exit, missing entry, exit dates disagree) Regulation (EU) 2017/2226 (EES) Regulation (EU) 2017/2226, Art. 12(1) “automatically identify which entry/exit records do not have exit data immediately following the date of expiry of an authorised stay”	explains a likely missing exit as the days after the traveller left is an exit disagreement, not a missing entry	Not a calculator feature	TS07TS13TS14TS47TS48
R10 EES: stays that began before 10 April 2026 are not compared End of the EES progressive start, 10 April 2026 Regulation (EU) 2025/1534, Art. 2(1) “'progressive start of operations of the EES' means the period of 180 days starting from the date from which the EES is to start operations” Regulation (EU) 2025/1534, Art. 5(6)(a) “National authorities and Europol shall disregard ... the results of the automated calculator ... referred to in Article 11 of Regulation (EU) 2017/2226”	drops the whole pre-cutoff stay, including days after 10 April (judging-day case) still flags a real gap in stays after the cutoff uses the reconciler's own figures	Not a calculator feature	TS30TS31TS38
R11 The correction request cites Article 52(1)–(5) and its deadlines Regulation (EU) 2017/2226, Art. 52 Regulation (EU) 2017/2226, Art. 52(1)–(3) “shall reply to such requests within 45 days of receipt ... check the accuracy of the data ... within 30 days ... rectify, complete or erase the personal data”	states 52(1)–52(5) separately and accurately cites the Article 52(1) 45-day reply duty for the responsible or receiving Member State	Not a calculator feature	TS08TS15TS17TS18TS49TS50
R12 The count agrees with the European Commission's own calculator Commission short-stay calculator	matches the stored Commission calculator on all 14 scenarios	No previous stay Calculator's built-in example	TS02TS51TS57TS65

The other 14 TestSprite tests

Not tied to one rule: they check the interface, navigation and keyboard behaviour. Same latest cloud run as above.

Test	Checks	Latest
TS05	Deleting a trip can be undone and the same trip comes back	passed
TC011	Trips persist after reloading the page	passed
TS16	A demo scenario carries to the EES check with the same numbers	passed
TS36	/proof lists every rule with its tests	passed
TS37	Scenario gallery cards open the history they describe	passed
TS40	Unknown address: 404 page leads back to every page	passed
TS41	Trip sheet takes focus, makes the page inert, and gives it back	passed
TS53	The developers page documents the API and its OpenAPI document lists the three endpoints	passed
TS55	Cancelling the trip sheet saves nothing	passed
TS56	Deleting every example trip returns to the empty state, 0 used and 90 left	passed
TS58	The skip link is the first Tab stop and moves focus to the main content	passed
TS59	Footer links open /proof and /developers	passed
TS63	The landing band switches from the example to the saved trips after a reload	passed
TS64	Trips saved on the calculator are the ones the EES check compares: 10 days, a 4-day gap to an EES figure of 14	passed