flaky test: t0030-install.sh ('ipfs-update install' works when something is installed)

[galargh]

Version information:

I have spotted the flakiness on this commit: 10bb4f2

Description:

During sharness tests execution with go 1.16 on #148, the first run failed (https://github.com/ipfs/ipfs-update/runs/4284444522?check_suite_focus=true) and the rerun passed (https://github.com/ipfs/ipfs-update/runs/4284859660?check_suite_focus=true) without any code changes.

Command Output:

Verbose Output

*** t0030-install.sh ***
./t0030-install.sh
ok 1 - start a docker container
ok 2 - 'ipfs-update install' works
ok 3 - 'ipfs-update install' output looks good
ok 4 - 'ipfs-update version' works
ok 5 - 'ipfs-update version' output looks good
not ok 6 - 'ipfs-update install' works when something is installed
#	
#		exec_docker "$DOCID" "$GUEST_IPFS_UPDATE --verbose install v0.4.23" >actual 2>&1 ||
#		test_fsh cat actual
#	
ok 7 - 'ipfs-update install' fails when downgrading without the downgrade flag
ok 8 - 'ipfs-update install' works when downgrading with flag
ok 9 - 'ipfs-update install' output looks good
ok 10 - 'ipfs-update version' works
ok 11 - 'ipfs-update version' output looks good
ok 12 - stop a docker container
# failed 1 among 12 test(s)
make: *** [Makefile:34: t0030-install.sh] Error 1