Black does not capture cases of strings separated by a space

[aveach]

Description:
Looks like in cases where a continuous string is written with a space, black incorrectly formats it as two separate strings.

Steps to Reproduce:
Block in file that needs formatting in file:

help='Drops purgeable caches before taking the footprint to reduce '
'run-to-run variance'

Running: black . changes it to:

help="Drops purgeable caches before taking the footprint to reduce " "run-to-run variance",

Environment:

• Version: 19.10b0
• OS and Python version: Ubuntu 18.04 -- Python3.6.10

Does this bug also happen on master?
Yes

[chevignon93]

This doesn't look like a continuous string with a space to me.

[ichard26]

I agree with chevignon93, the example provided is not a continuous string with a space.
A quick sanity check of print(help) returns "Drops purgeable caches before taking the footprint to reduce ".

Regardless of that, I haven't been able to reproduce the bug on my local machine, nor on the Black Playground on master and stable.

Environment

1. Version: 19.10b0
2. OS and Python version: Windows 10 Home Edition Build 18363 & CPython 3.8.1

[JelleZijlstra]

If the intended bug here is that the strings aren't merged, this is a duplicate of #26.