test failed in CI: test_action_failure_can_unwind_no_pantry

As seen in https://github.com/oxidecomputer/omicron/issues/7731 and https://github.com/oxidecomputer/omicron/issues/7551, but this seems like a different flake mode? I wouldn't be surprised if this is more closely related to 7731 though.

This test failed in a CI run on https://github.com/oxidecomputer/omicron/pull/8728:

Log showing the specific test failure:

https://buildomat.eng.oxide.computer/wg/0/details/01K5CRKT4BRQZNCGR0YX0T9FNS/gs2sRBxOJ3N0uak0e7vbD0IHYNK1WvQu8YkenbimiD3ZqnN4/01K5CRN247N8KCCMSRXXJP1R9F

Excerpt from the log showing the failure:

7104  2025-09-17T22:21:14.076Z    stderr ─── 
7105  2025-09-17T22:21:14.076Z      log file: /var/tmp/omicron_tmp/omicron_nexus-7c3777add95cb98d-test_action_failure_can_unwind_no_pantry.12907.0.log
7106  2025-09-17T22:21:14.076Z      note: configured to log to "/var/tmp/omicron_tmp/omicron_nexus-7c3777add95cb98d-test_action_failure_can_unwind_no_pantry.12907.0.log"
7107  2025-09-17T22:21:14.076Z      DB URL: postgresql://root@[::1]:55473/omicron?sslmode=disable
7108  2025-09-17T22:21:14.076Z      DB address: [::1]:55473
7109  2025-09-17T22:21:14.076Z      log file: /var/tmp/omicron_tmp/omicron_nexus-7c3777add95cb98d-test_action_failure_can_unwind_no_pantry.12907.2.log
7110  2025-09-17T22:21:14.076Z      note: configured to log to "/var/tmp/omicron_tmp/omicron_nexus-7c3777add95cb98d-test_action_failure_can_unwind_no_pantry.12907.2.log"
7111  2025-09-17T22:21:14.076Z  
7112  2025-09-17T22:21:14.076Z      thread 'app::sagas::snapshot_create::test::test_action_failure_can_unwind_no_pantry' panicked at /work/oxidecomputer/omicron/nexus/test-utils/src/resource_helpers.rs:222:13:
7113  2025-09-17T22:21:14.076Z      failed to make "DELETE" request to /v1/disks/disky-mcdiskface?project=springfield-squidport: making request to server
7114  2025-09-17T22:21:14.076Z      stack backtrace:
7115  2025-09-17T22:21:14.076Z         0: __rustc::rust_begin_unwind
7116  2025-09-17T22:21:14.076Z                   at /rustc/29483883eed69d5fb4db01964cdf2af4d86e9cb2/library/std/src/panicking.rs:697:5
7117  2025-09-17T22:21:14.076Z         1: core::panicking::panic_fmt
7118  2025-09-17T22:21:14.076Z                   at /rustc/29483883eed69d5fb4db01964cdf2af4d86e9cb2/library/core/src/panicking.rs:75:14
7119  2025-09-17T22:21:14.076Z         2: nexus_test_utils::resource_helpers::object_delete::{{closure}}::{{closure}}
7120  2025-09-17T22:21:14.076Z                   at ./test-utils/src/resource_helpers.rs:222:13
7121  2025-09-17T22:21:14.076Z         3: core::result::Result<T,E>::unwrap_or_else
7122  2025-09-17T22:21:14.076Z                   at /rustc/29483883eed69d5fb4db01964cdf2af4d86e9cb2/library/core/src/result.rs:1521:23
7123  2025-09-17T22:21:14.076Z         4: {async_fn#0}
7124  2025-09-17T22:21:14.076Z                   at ./test-utils/src/resource_helpers.rs:221:10
7125  2025-09-17T22:21:14.077Z         5: {async_fn#0}
7126  2025-09-17T22:21:14.077Z                   at ./test-utils/src/resource_helpers.rs:543:33
7127  2025-09-17T22:21:14.077Z         6: {async_block#0}
7128  2025-09-17T22:21:14.077Z                   at ./src/app/sagas/snapshot_create.rs:2383:66
...

Notably this is a failure to make the DELETE request, but the test had been running for >600 seconds at that point and the test Nexus had processed a DELETE a few seconds earlier. So my wild guess is that here and #7731 are us witnessing a timeout getting reached and the test environment coming down around the test runner.

Start with app::sagas::snapshot_create::test::test_action_failure_can_unwind_no_pantry and the failure path in test-utils/src/resource_helpers.rs around lines 221-222 and 543. Review the linked CI log and compare issues 7731 and 7551 to determine whether the DELETE failure is caused by test-environment shutdown or another flake mode. Done means the failure mode is understood and the test no longer flakes in CI.