konsti a647f31600 Don't add a magic trailing comma for a single entry (#5463) ...

## Summary

If a comma separated list has only one entry, black will respect the
magic trailing comma, but it will not add a new one.

The following code will remain as is:

```python
b1 = [
    aksjdhflsakhdflkjsadlfajkslhfdkjsaldajlahflashdfljahlfksajlhfajfjfsaahflakjslhdfkjalhdskjfa
]
b2 = [
    aksjdhflsakhdflkjsadlfajkslhfdkjsaldajlahflashdfljahlfksajlhfajfjfsaahflakjslhdfkjalhdskjfa,
]
b3 = [
    aksjdhflsakhdflkjsadlfajkslhfdkjsaldajlahflashdfljahlfksajlhfajfjfsaahflakjslhdfkjalhdskjfa,
    aksjdhflsakhdflkjsadlfajkslhfdkjsaldajlahflashdfljahlfksajlhfajfjfsaahflakjslhdfkjalhdskjfa
]
```

## Test Plan

This was first discovered in
7eeadc82c2/django/contrib/admin/checks.py (L674-L681),
which i've minimized into a call test.

I've added tests for the three cases (one entry + no comma, one entry +
comma, more than one entry) to the list tests.

The diffs from the black tests get smaller.

2023-07-03 21:48:44 +02:00

..

test/fixtures

Don't add a magic trailing comma for a single entry (#5463)

2023-07-03 21:48:44 +02:00