Hi Martin, what you observed happens if /tmp is on a partition mounted with noatime. In this case sorting by access time can not produce the result expected by that failing test. If /tmp is mounted with either atime or relatime the tests run just fine.
I think it's best to report this upstream and wait what they say about it. For the time being I'll reopen this bug by lowering the severity to minor (since none of Debian's systems involved in building symfony seem to mount /tmp with noatime). Greetings Daniel PS: Martin, have might want to switch from noatime to relatime or even lazytime (Linux kernel 4.0 and up).
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