Allow custom "now" in naturaldelta and naturaltime

[phijor]

This allows having a different point in time to which a value is compared.
Useful if one is dealing with datetimes that are not in the local timezone.

Fixes #55.

Changes proposed in this pull request:

• both naturaldelta and naturaltime now expose an optional now parameter
• both methods may now be used with datetime objects that are not in the local timezone

[codecov-commenter]

Codecov Report

Merging #144 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #144   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            9         9           
  Lines          560       569    +9     
=========================================
+ Hits           560       569    +9     

Flag	Coverage Δ
#GHA_Ubuntu	100.00% <100.00%> (ø)
#GHA_Windows	100.00% <100.00%> (ø)
#GHA_macOS	100.00% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/humanize/time.py	100.00% <100.00%> (ø)
tests/test_time.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 55b3e1c...b37dc30. Read the comment docs.

[phijor]

So... yeah, black seems to be fighting flake8 here. I cannot put the test cases on multiple lines (black folds them into one), but having them folded into one line by black results in a trailing comma which flake8 does not like. 🤯

[hugovk]

Thank you for the PR!

So now could be another timezone, or in the past or future. Would it be better to call it when?

For example now=yesterday or now=next_week might be better as when=yesterday or when=next_week?

So... yeah, black seems to be fighting flake8 here. I cannot put the test cases on multiple lines (black folds them into one), but having them folded into one line by black results in a trailing comma which flake8 does not like. 🤯

Yeah, it's a bit annoying, I think psf/black#1288 is the issue for that.

[phijor]

Thank you for the PR!

Thank you for your feedback :) Date, time and timezones are confusing.

So now could be another timezone, or in the past or future. Would it be better to call it when?

For example now=yesterday or now=next_week might be better as when=yesterday or when=next_week?

Calling it when sounds like a good idea. I'll push some changes and resolve conflicts in next few days.

My use case for this is as follows: I have a pair of datetime objects, current_time and starting_time. I cannot control which timezone they are in, but I can assume that it is the same for both of them. Now I want to print (in a human readable way) when starting_time happened, relative to current_time. Something like

>>> (
    f"starting_time is {naturalday(starting_time)}, "
    f"which was {naturaltime(starting_time, when=current_time)}"
)
"starting_time is Jul 12, which was 10 days ago"

Usually it would make sense to just use naturaltime(current_time - starting_time), but the current implementation (date_and_delta) insists on calculating a date relative to _now(), so that won't work. Maybe we can even work around that without having to add a when parameter by refactoring date_and_delta.

[phijor]

I was about to update this PR (finally), but it seems like I have borked some tests.

Well, lets see what's wrong.

[phijor]

Huh... so it seems like datetime supports subtraction of values in different timezones? Way to subvert my expectations. It just does not like to compare values where tz=None in one operand.

I will squash all these fixup commits before merging.

[hugovk]

Ping me when you're ready for re-review :)

[phijor]

Ping! @hugovk

[hugovk]

Thank you! Just a little docstring nit.

[hugovk]

Please can you change this example to use import datetime as dt and dt.datetime etc?

Rationale: https://adamj.eu/tech/2019/09/12/how-i-import-pythons-datetime-module/

[hugovk]

Thank you!