ci: typecheck the test tree too (C-03)

[jpr5]

What

tsconfig.json excludes src/__tests__, so the 180-file / 5,638-test suite has never been type-checked. The typecheck CI job added in #402 covers src/ and scripts/ only.

Removing the exclude line does not work. The root project pins rootDir: "src", and tests import across into scripts/ — that produces 11 TS6059 rootDir violations. This needed its own project, as the plan said.

The tsconfig split

New tsconfig.test.json:

• extends: "./tsconfig.json" — same strict, same target/module/resolution, so the tests are held to the same bar as src/.
• rootDir: "." and declaration: false — both are emit-shape settings, and this project is --noEmit. Dropping rootDir is what removes the 11 TS6059s without weakening a single check.
• include: ["src", "vitest.config.ts", "vitest.config.drift.ts"], exclude: ["node_modules", "dist"] — the tests are in, and the two vitest configs get covered for free.

pnpm typecheck now runs tsc -p tsconfig.json && tsc -p tsconfig.test.json && tsc -p scripts/tsconfig.json. No workflow change — the existing typecheck job already runs pnpm typecheck.

Program membership, not just a green exit: tsc -p tsconfig.test.json --listFiles | grep -c src/__tests__ = 223 (vs 0 for the root project).

Measured, not carried forward

	plan	measured on 3a1b1de
errors	126	115
files	~40	29

By code: 38×TS2345, 21×TS2352, 17×TS2531, 8×TS18048, 6×TS2339, 6×TS2322, 5×TS2769, 4×TS2683, 4×TS2554, 3×TS2741, 1×TS5097, 1×TS2353, 1×TS18047.

TS6059 shows as 0 here only because this config drops rootDir. The naive fix still hits all 11 — see proof 1b below.

No suppressions

No as any, no @ts-ignore, no @ts-expect-error, no new eslint-disable, no widened exclude, no file relocation. git diff | grep -E '^\+.*(as any|@ts-ignore|@ts-expect-error|eslint-disable)' → empty.

Real defects the gate caught:

• isFamilyStillReferenced takes one argument; four calls in models.drift.ts passed two. The second argument was silently discarded.
• recorder-path-traversal.test.ts set endpoint: "/v1/chat/completions", which is not in the FixtureMatch["endpoint"] union at all. The value is "chat".
• HandlerDefaults.replaySpeed is required and 24 test defaults literals omitted it.
• createMockRes().writeHead modelled only one of Node's two overloads — it would have thrown away headers on a (status, statusMessage, headers) call.
• competitive-matrix.test.ts imported a .ts extension; every other test uses .js, which resolves the same under NodeNext.

The rest are honest assertions where the type is genuinely nullable (JournalEntry.body), narrowing that never happened (let x: T | undefined = await new Promise(...) — the promises are now explicitly generic), or missing required fields (AGUIMessage.id, AGUIRunAgentInput.threadId/runId, SSEChoice.logprobs). Two as AGUIRunAgentInput casts are deleted because the literals became valid.

Where a cast was genuinely needed, it is one documented single-site helper (looseEntry in fix-drift.test.ts, isRestorableSpy in fixture-loader.test.ts) rather than a scatter of double casts.

Red-green proof

1 — RED, the real state. origin/main @ 3a1b1de in a clean worktree, tsconfig.test.json dropped in, nothing else changed:

RED RC=2
115 errors
29 files

1b — the structural blocker is real. On the same pristine tree, the naive fix (delete src/__tests__ from exclude, keep rootDir):

$ npx tsc -p tsconfig.naive.json --noEmit 2>&1 | grep -c "error TS6059"
11
scripts/drift-report-collector.ts(41,8): error TS6059: File '.../scripts/drift-types.ts' is not under 'rootDir' '.../src'.

Exactly the 11 the plan predicted.

2 — GREEN on the real tree.

$ pnpm typecheck ; echo $?
> tsc -p tsconfig.json --noEmit && tsc -p tsconfig.test.json --noEmit && tsc -p scripts/tsconfig.json --noEmit
0

3 — the gate FAILS on a deliberate error. Appended to src/__tests__/jsonrpc.test.ts:

const deliberateTypeError: number = "C-03 gate must catch this";

$ pnpm typecheck ; echo $?
src/__tests__/jsonrpc.test.ts(517,7): error TS2322: Type 'string' is not assignable to type 'number'.
 ELIFECYCLE  Command failed with exit code 2.
2

4 — removed, green again.

$ pnpm typecheck ; echo $?
0

Gates

gate	exit
prettier --check .	0
npx eslint .	0
pnpm typecheck	0
npx vitest run	0
npx commitlint --from origin/main --to HEAD	0

Suite unchanged against baseline: 179 passed / 1 skipped (180 files), 5592 passed / 46 skipped (5638 tests). No workflow touched, so no actionlint. No dependency change, so no lockfile drift.

Nothing left unfixed

All 115 are fixed. Zero remainder.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@copilotkit/aimock@404

commit: f202e41