added usage of subtest for etl

[eklatzer]

One of #2098

[github-actions]

Dear eklatzer

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[eklatzer]

CI error: --- FAIL: TestSeedWithTime (0.00s) animal_magic_test.go:22: SeedWithTime always sets the same seed
The example uses time.Now().UnixNano()) so it should be fine, therefore I added a constant offset and the test should not fail again

[andrerfcsantos]

Just an extra file here and a file missing a newline at the end.