Summary

• Replaces the bare expect(spans).toHaveLength(8) + findSpans.length === 3 + isMasterSpans.length === 2 triple in suites/tracing/mongodb/test.ts with a single toEqual on the per-db.operation breakdown.

Why

From the failing run:

AssertionError: expected [ { …(10) }, { …(10) }, …(7) ] to have a length of 8 but got 9
> 124 |          expect(spans).toHaveLength(8);

The previous assertion told us "8 expected, 9 received" — but nothing about which operation drifted. With this change, when the test fails the same way again, the diff is:

- Expected
+ Received

  Object {
    "find": 3,
-   "isMaster": 2,
+   "isMaster": 3,
    "insert": 1,
    "update": 1,
    "endSessions": 1,
  }

— pointing the next investigator straight at the extra isMaster (or whichever command actually drifted). The flake itself isn't fixed here; the goal is that the next occurrence is self-diagnosing instead of opaque.

Detail

The scenario at mongodb/scenario.mjs issues 8 commands: 2 isMaster (from connect()), 1 insert, 3 find (one each from the two findOne calls plus the find().toArray()), 1 update, 1 endSessions (from client.close()). The new assertion encodes that exact breakdown.

db.operation isn't set on endSessions spans — they only expose the command name via db.statement. The classifier falls back to parsing the leading {"<command>" token out of db.statement for that case.

The toContainEqual matchers for span shape (find/insert/isMaster/update/endSessions) are unchanged.

Fixes #20781

🤖 Generated with Claude Code