Plan 022: Test the export pipeline (characterization tests for the flagship path)

Executor instructions: Follow this plan step by step. Run every verification command and confirm the expected result. If anything in "STOP conditions" occurs, stop and report. When done, update the status row in plans/README.md.

Drift check (run first): git diff --stat c63cb120..HEAD -- packages/slidev/node/commands/export.ts On a mismatch with the excerpts below, treat it as a STOP condition.

Status

• Priority: P1
• Effort: M
• Risk: LOW
• Depends on: none (unblocks 023; overlaps 009/016/021's helper tests)
• Category: tests
• Planned at: commit c63cb120, 2026-07-10

Why this matters

slidev export (PDF/PNG/PPTX) is a flagship feature (README) implemented in a 658-line file with zero tests. Regressions in page-range selection, TOC outline building, or filename handling ship undetected; CI only runs slidev build in smoke, never export. Characterization tests over the pure helpers give a fast safety net now (no Playwright needed) and are the prerequisite for safely decomposing the module (plan 023).

Current state

packages/slidev/node/commands/export.ts pure/near-pure helpers worth pinning:

• getExportOptions(args, options, outFilename?) (:574-624) — merges CLI args + deck config into an ExportOptions; exported already.
• addToTree (:51-67) + makeOutline (:69-77) — TOC → PDF outline string (module-internal; not currently exported). NB: plan 021 may move addToTree into @slidev/parser as buildTocTree — if 021 has landed, test the shared builder instead and only test makeOutline here.
• parseRangeString (from @slidev/parser) drives page selection at :189 — its own tests are plan 009; here, assert getExportOptions/range interplay.
• The gen* render functions need Playwright + a running preview → out of scope for unit tests; covered by the optional smoke in Step 3.

Test patterns available: colocated *.test.ts with Vitest (see packages/slidev/node/syntax/*.test.ts) using describe/it/expect and toMatchInlineSnapshot.

Commands you will need

Purpose	Command	Expected
Install	pnpm install	exit 0
Build	pnpm build	exit 0
Test	pnpm test -- export	new tests pass
Typecheck	pnpm typecheck	exit 0

Scope

In scope:

• packages/slidev/node/commands/export.ts — export addToTree/makeOutline (or import the shared builder from 021) so they're testable; no behavior change
• packages/slidev/node/commands/export.test.ts (create) — unit tests

Out of scope:

• Refactoring the gen* closures (plan 023).
• Browser teardown / filename confinement (plans 007/016 — their helpers may add their own tests; don't duplicate).
• Setting up a Playwright CI job (the optional smoke in Step 3 is local-only unless the operator wants it wired into CI).

Git workflow

• Branch: test/export-pipeline.
• Conventional commit: test(export): characterize export helpers.
• Do NOT push/PR unless instructed.

Steps

Step 1: Make the pure helpers importable

If addToTree/makeOutline are still local to export.ts, add export to them (or, if plan 021 landed, import buildTocTree from @slidev/parser). Do not change their logic.

Step 2: Write characterization tests

Create packages/slidev/node/commands/export.test.ts covering:

• getExportOptions: given representative args + a fake ResolvedSlidevOptions (minimal data.config + data.slides), assert the resolved format, output (default ${basename(entry,'.md')}-export), width/height from canvasWidth/aspectRatio, withClicks default for pptx, range, and scale defaults. Snapshot the returned object.
• makeOutline (and addToTree/buildTocTree): build a small tree from a handful of titled slides at mixed levels and snapshot the outline string (path|--|title lines), including a nested case.
• range interplay: assert parseRangeString(total, range) (imported from @slidev/parser) selects the expected pages for a couple of inputs the exporter relies on (e.g. '2-3', undefined).

Keep fixtures inline/synthetic — no real rendering, no fs writes.

Verify: pnpm build && pnpm test -- export → all new tests pass.

Step 3 (optional, local-only): a Playwright smoke

Only if the operator wants render coverage and playwright-chromium is available: add a slow/opt-in test (or a cypress/script harness) that builds the demo, serves it, runs exportSlides for a 2-slide deck to each format, and asserts the output file exists with a plausible page count/size. Gate it so it does not run in the default pnpm test (e.g. behind an env flag) unless CI is set up for Playwright. STOP and ask before adding a browser dependency to the default CI.

Test plan

• New export.test.ts pins getExportOptions, outline building, and range selection — the regressions most likely to slip through today.
• Optional Playwright smoke (Step 3) is the only true end-to-end; keep it opt-in.

Done criteria

• packages/slidev/node/commands/export.test.ts exists and passes
• getExportOptions, outline building, and range selection are covered
• No behavior change to export.ts beyond adding export keywords
• Default pnpm test does not require Playwright/a browser
• pnpm build && pnpm typecheck exit 0
• Only in-scope files modified (git status)
• plans/README.md status row updated

STOP conditions

Stop and report if:

• Making a helper importable would require broad refactoring (it shouldn't — just an export keyword) — that means the code has drifted; report.
• The operator has not approved adding Playwright to CI (keep Step 3 local/opt-in).

Maintenance notes

• These are characterization tests: if they fail after an intentional change, update the snapshot deliberately, not reflexively.
• This suite is the safety net plan 023 relies on before decomposing exportSlides.
• Reviewer: confirm the fake ResolvedSlidevOptions in tests stays minimal and doesn't couple tests to unrelated config.