precisedelta with minimum unit seconds fails when seconds is a very small value

[riisi]

What did you do?

Calculated a small delta.

import humanize
from datetime import timedelta
duration_seconds = 1e-06       # A small value, or 0
delta = timedelta(seconds=duration_seconds)
output = humanize.precisedelta(delta, minimum_unit="minutes")
print(output)

What did you expect to happen?

Output would be 0 seconds.

Alternatively, a better error message or a warning in the documentation would be helpful.

What actually happened?

>       tail = texts[-1]
E       IndexError: list index out of range

What versions are you using?

• OS: ubuntu
• Python: 3.6.12
• Humanize: 2.6.0

[hugovk]

precisedelta was added in #137.

@eldipa Please could you have a look?

[eldipa]

What it is happening is that if the delta is in microseconds (lower than 1 second to be precise) and the minimum unit is greater than seconds (like minutes), the microseconds are not propagated to the upper units (like minutes) so it computes "0".

Because the function then ignores all the zeros (so we avoid "0 years, 0 hours, 3 secs"), the function crashes later because it deleted all the values (like "0 years, 0 hours").

The most sane fix is to catch this corner case and say "0 minutes" for example.

I left a PR with the proposed fix (sorry for the delay).