dev/core#938 Stabalize Attachment API Test

[seamuslee001]

Overview

This aims to ensure that tests are more stable, by testing each stable part separately and only allow a deviation by 1 on the timestamp

Before

Test can be flaky

After

Test stable

ping @demeritcowboy @eileenmcnaughton @totten

[civibot]

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[seamuslee001]

Jenkins re test this please

[seamuslee001]

https://lab.civicrm.org/dev/core/issues/938

[demeritcowboy]

@seamuslee001 Thanks that seems like a good compromise to avoid touching the security fix code. But should the tolerance parameter be 2? That approxEquals function was new to me so I looked at it and the comparison is a strict less than, so the way I read it a tolerance of 1 actually means zero tolerance for integers?