UnauthorizedAccessException when running on Linux

[jmezach]

I recently tried running this module on a hosted Linux agent and the good news is that it works, almost. I'm getting an UnauthorizedAccessException: Access to the path '/' is denied. The exception makes sense of course, but the question is why it is writing things to root. I had a look at the logs and this is what I'm seeing:

VERBOSE: received 390-byte response of content type application/json
VERBOSE: Received <redacted>
VERBOSE: Creating output folder: '/home/vsts/work/_temp/TestResults'
VERBOSE: GET https://dev.azure.com/<org>/<team-project>/_apis/test/Runs/1594766/attachments?api-version=5.0-preview.1 with 0-byte payload
VERBOSE: received 389-byte response of content type application/json
VERBOSE: Received <redacted>
VERBOSE: Downloading 'https://dev.azure.com/<org>/<team-project>/_apis/test/Runs/1594766/Attachments/1' to '/home/vsts/work/_temp/TestResults/_fv-az104_2020-09-16_09_45_15.trx'
VERBOSE: GET https://dev.azure.com/<org>/<team-project>/_apis/test/Runs/1594766/Attachments/1 with 0-byte payload
VERBOSE: received -byte response of content type application/octet-stream
VERBOSE: Downloading TRX: _fv-az104_2020-09-16_09_45_15.trx
VERBOSE: Configuring TRX folder: /home/vsts/work/_temp/TestResults/_fv-az104_2020-09-16_09_45_15
VERBOSE: Processing attachments
VERBOSE: fv-az104/coverage.cobertura.xml  => fv-az104
VERBOSE: The file 'coverage.cobertura.xml' will be stored at '/home/vsts/work/_temp/TestResults/_fv-az104_2020-09-16_09_45_15/In/fv-az104'
VERBOSE: Creating output location: '/home/vsts/work/_temp/TestResults/_fv-az104_2020-09-16_09_45_15/In/fv-az104'
VERBOSE: Downloading coverage.cobertura.xml
VERBOSE: Writing coverage.cobertura.xml to /
VERBOSE: Downloading 'https://dev.azure.com/<org>/<team-project>/_apis/test/Runs/1594766/Attachments/3' to '/'
VERBOSE: GET https://dev.azure.com/<org>/<team-project>/_apis/test/Runs/1594766/Attachments/3 with 0-byte payload
VERBOSE: received -byte response of content type application/octet-stream
VERBOSE: System.UnauthorizedAccessException: Access to the path '/' is denied.

Looking at the code it seems that this is where things started to go wrong. For some reason the targetLocations variable there doesn't have a value, causing the output folder to be /. Haven't managed to dig any deeper than that. Running the exact same thing works as expected on Windows, so it's probably a silly platform specific thing.