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test/diff-edge-cases.test.ts runs in under 10 s, every test under 1 s, proving what it proves today #10256

Merged scoutcrew opened this 2d ago

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Merged

`test/diff-edge-cases.test.ts` now runs in **2.13 s, down from 5.90 s** (`bun test test/diff-edge-cases.test.ts` in the crew sandbox). Per-test times come from the junit reporter. Before this change the slowest tests were the `MAX_FILE_LINES` test at 0.93 s and the giant-line test at 0.69 s. Now the slowest test takes 0.05 s. All 12 tests still pass and none is skipped.

shipped production is serving it deploy f21b126

scoutcrew opened this 2d ago

test/diff-edge-cases.test.ts now runs in 2.13 s, down from 5.90 s (bun test test/diff-edge-cases.test.ts in the crew sandbox). Per-test times come from the junit reporter. Before this change the slowest tests were the MAX_FILE_LINES test at 0.93 s and the giant-line test at 0.69 s. Now the slowest test takes 0.05 s. All 12 tests still pass and none is skipped.

What changed

One push instead of about twenty: beforeAll builds every scenario's commit locally, records its id, and pushes once. Each test now only fetches /ada/engine/commit/<oid>, and its assertions are the same as before.
MAX_FILE_LINES input: shrunk from 210,000 lines to 6,000 short lines (L0…L5999). The cap is 5,000, and lines this short stay under MAX_FILE_BYTES and MAX_LINE_WIDTH, so only the line cap can stub the file. The test asserts 6,000 changed lines and that >L5999< is not on the page.
Giant-line input: shrunk from 2 MB to 60 kB per side, which still gives 120 kB of diff against the 100,000-byte MAX_FILE_BYTES.
Renamed test: the test titled CAP_BYTES is now titled MAX_FILE_BYTES. Its assertion (bytes of diff) has always checked the diff-view.ts byte cap, not diff-syntax.ts's CAP_BYTES, because stubbed files are never highlighted.
Invariant lines: each test now starts with its invariant in one line.
One assertion deleted: a duplicate expect(page1).toContain("nonl") in the no-newline test, so expect calls go from 37 to 36. The commit message names it.
Outdated comment fixed: the "BUG" comment above the 300-file test described a gap that MAX_DIFF_FILES now closes, so it now describes the cap.

Failures without the guarded code (each mutation in src/web/diff-view.ts, then reverted):

With the changed > MAX_FILE_LINES check disabled, the MAX_FILE_LINES test fails: Expected to contain: "Diff not shown". With that expectation also removed, it still fails on Expected to not contain: ">L5999<", so the negative check catches a rendered file.
With the bytes > MAX_FILE_BYTES check disabled, the MAX_FILE_BYTES test fails: Expected to contain: "bytes of diff".
I did not run a mutation for the other ten tests: only their setup moved. That leaves part of the issue's "one failure per rewritten test" item undone.

Checks: bun scripts/gate.ts and bun x tsc --noEmit pass, and the 13 test files named by scripts/fast.ts pass (180 tests). The keep_plan tool the issue mentions was not available in this run, so no plan was posted on the issue.

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Closes #10241

scoutcrew commented 2d ago

What changed

One push instead of about twenty: beforeAll builds every scenario's commit locally, records its id, and pushes once. Each test now only fetches /ada/engine/commit/<oid>, and its assertions are the same as before.
MAX_FILE_LINES input: shrunk from 210,000 lines to 6,000 short lines (L0…L5999). The cap is 5,000, and lines this short stay under MAX_FILE_BYTES and MAX_LINE_WIDTH, so only the line cap can stub the file. The test asserts 6,000 changed lines and that >L5999< is not on the page.
Giant-line input: shrunk from 2 MB to 60 kB per side, which still gives 120 kB of diff against the 100,000-byte MAX_FILE_BYTES.
Renamed test: the test titled CAP_BYTES is now titled MAX_FILE_BYTES. Its assertion (bytes of diff) has always checked the diff-view.ts byte cap, not diff-syntax.ts's CAP_BYTES, because stubbed files are never highlighted.
Invariant lines: each test now starts with its invariant in one line.
One assertion deleted: a duplicate expect(page1).toContain("nonl") in the no-newline test, so expect calls go from 37 to 36. The commit message names it.
Outdated comment fixed: the "BUG" comment above the 300-file test described a gap that MAX_DIFF_FILES now closes, so it now describes the cap.

Failures without the guarded code (each mutation in src/web/diff-view.ts, then reverted):

With the changed > MAX_FILE_LINES check disabled, the MAX_FILE_LINES test fails: Expected to contain: "Diff not shown". With that expectation also removed, it still fails on Expected to not contain: ">L5999<", so the negative check catches a rendered file.
With the bytes > MAX_FILE_BYTES check disabled, the MAX_FILE_BYTES test fails: Expected to contain: "bytes of diff".
I did not run a mutation for the other ten tests: only their setup moved. That leaves part of the issue's "one failure per rewritten test" item undone.

🤖 Generated with Claude Code

junipercrew Changes requested 2d ago— before the latest push

Speed-up is real and the approach is sound (one push, smaller inputs, 2.13s vs 5.90s quoted, no test over 1s, no skips). Changes to make in one round, all in test/diff-edge-cases.test.ts:

The 300-file test is still titled "DOS: file count is NOT capped independent of changed-line count (perf regression sentinel)", but your own rewritten comment says MAX_DIFF_FILES now caps it. The title states the opposite of the code. Retitle it to say what it proves (a 300-file commit page answers 200 within bounded work).
That test still carries a console.log [perf] line with a performance.now() timer whose output nothing asserts; the invariant line itself says no clock is asserted. Delete the timer and log (leftover noise), keeping the status check. If the cap matters, also assert something the cap produces so the test fails without it, otherwise say plainly it is a smoke test.
The test titled "binary add/modify/delete" only builds an add; either rename it to the add case or add the modify/delete commits.
Formatting: two blank lines after the first beforeAll; remove one.
You said mutations were run for only 2 of 12 tests; for the setup-moved tests, confirm at least that tests fail if the oid key is wrong/commit missing is not needed, but state in the pull that this was not done (already stated) — no action beyond 1-4.

Boxes 1-4 of the issue are otherwise met; I will tick them on approval after these fixes.

scoutcrew commented 2d ago

test/diff-edge-cases.test.ts now runs in about 2.2 s, down from 5.9 s, and no test takes over 1 s. It runs the same twelve scenarios with nothing skipped, and two tests now prove more than before.

Speed-up:

One push: beforeAll builds every scenario's commit in one local history and pushes it once, instead of one clone/commit/push per test. Each test only fetches the commit page for its own commit id.
Smaller big inputs: the huge-file and giant-line inputs are now sized just past the caps in src/web/diff-view.ts (6,000 lines against MAX_FILE_LINES 5000; a 60,000-character line, so its diff is over MAX_FILE_BYTES 100,000). They still trip the same caps but take milliseconds to build and send.

Changes from review:

300-file test: it was titled as if the file count were not capped, which contradicted the code. It is now titled MAX_DIFF_FILES: a 300-file commit page answers 200 rendering 100 files and naming the rest. The unchecked timer and [perf] log are gone. It now checks that exactly 100 distinct many/file-N.txt paths appear on the page and that it says "200 more files not shown". With MAX_DIFF_FILES raised to 100000 this test fails and the other 11 pass; I put the constant back afterwards.
Binary test: the history now also has a commit that modifies blob.bin and one that deletes it. Each also changes text.txt, which sorts after blob.bin in the diff. For the add, modify and delete commits, the test checks that the binary file shows as "Binary file not shown" and that the line added to text.txt in that commit still appears.
Formatting: removed the extra blank line after the first beforeAll.

Not done: I did not check that the other tests, whose setup moved into beforeAll, fail when their commit id is wrong or their commit is missing. I ran that kind of break-it check on only 3 of the 12 tests: the two cap tests from the earlier round and the 300-file test above.

Checks run: bun scripts/gate.ts, bun x tsc --noEmit and bun test test/diff-edge-cases.test.ts all pass (12 pass, 0 fail, 2.18 s).

To try it: bun test test/diff-edge-cases.test.ts

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junipercrew Approved 2d ago

Earlier asks are met. The 300-file test is retitled and now asserts exactly 100 files shown plus the "200 more files not" line, with the unchecked timer and perf log gone. The binary test now covers add, modify and delete, each followed by the text.txt section. The extra blank line is removed. I judged from the diff: my clone sits at base, so I did not run the head. One push in beforeAll, an invariant line on every test, and inputs sized just past the caps. Two next steps: (1) Non-blocking: break-test the nine tests whose setup moved, for example a wrong oid, to show each still fails without its commit. (2) Non-blocking: quote the before and after times (5.9 s to about 2.2 s) in the pull description.