TFS 2017 build executing powershell failing due to term not recognized error on line 1 - powershell

Question

I'm pretty new to TFS and I'm still learning how to use it (so hopefully this isn't just a stupid oversight on my end). I'm working an internship this summer at a seasonal developer position, and essentially my end goal is to automate load testing for the company's website. I'm using TFS to achieve this goal; the build I currently have has two tasks only right now: one to start the controller and the testing environment, and one to stop them. My problem is that the build keeps failing before it really even starts, due to a "term not recognized" error on line 1, specifically caused by what appears to be the default working folder not being recognized.
Here are the relevant log files:
2019-05-30T20:00:02.0942883Z Executing the following powershell script. (workingFolder = D:\RM_agent\_work\11\s)
2019-05-30T20:00:02.0942883Z D:\RM_agent\_work\11\s
2019-05-30T20:00:02.4999117Z ##[error]. : The term 'D:\RM_agent\_work\11\s' is not recognized as the name of a
2019-05-30T20:00:02.4999117Z ##[error]cmdlet, function, script file, or operable program. Check the spelling of the
2019-05-30T20:00:02.4999117Z ##[error]name, or if a path was included, verify that the path is correct and try again.
2019-05-30T20:00:02.4999117Z ##[error]At line:1 char:3
2019-05-30T20:00:02.4999117Z ##[error]+ . 'D:\RM_agent\_work\11\s'
2019-05-30T20:00:02.4999117Z ##[error]+ ~~~~~~~~~~~~~~~~~~~~~~~~
2019-05-30T20:00:02.4999117Z ##[error] + CategoryInfo : ObjectNotFound: (D:\RM_agent\_work\11\s:String)
2019-05-30T20:00:02.4999117Z ##[error] [], CommandNotFoundException
2019-05-30T20:00:02.4999117Z ##[error] + FullyQualifiedErrorId : CommandNotFoundException
I know that the working folder defaults to $(Build.SourcesDirectory), so I'm assuming that D:\RM_agent\_work\11\s is what $(Build.SourcesDirectory) evaluates to. RM_agent is obviously an agent, so /_work/11/s should be the local path where it stores the source code. Why is it unrecognized then?
I tried manually setting the working folder for the scripts through tfs to the folder where the build is stored, but the build still failed and the logs still showed that workingFolder = D:\RM_agent\_work\11\s.
Additionally, the line of code that the build is failing on, Executing the following powershell script. (workingFolder = D:\RM_agent\_work\11\s), is nowhere in the script I am trying to execute, which confuses me. Where is this script coming from?
(I can remove this if it doesn't fit the guidelines/is off topic, but if anyone could point me towards any resources about tfs and/or load testing it would be massively helpful as well)
EDIT: Here is the powershell script for the first task
########################################
# start environment
########################################
# import modules
Import-Module '\\neenah-san1\TSbuild\Deployment\Tools\PowerShell\Azure\JJK.TS.Azure.psm1' -Force -Prefix 'TS'
# provide azure credentials
$credential = Get-Credential
# login to azure subscription
Login-AzureRmAccount -Credential $credential
# start the controller
Get-AzureRmVM -ResourceGroupName 'TS-LoadTest-TST' | Where-Object {$_.Name -match 'vstc'} | Start-TSAzureVM -Credential $credential
# wait for controller to fully start
Start-Sleep -Seconds 120
# start the agents
Get-AzureRmVM -ResourceGroupName 'TS-LoadTest-TST' | Where-Object {$_.Name -match 'vsta'} | Start-TSAzureVM -Credential $credential
# check status of all servers
Get-AzureRmVM -ResourceGroupName 'TS-LoadTest-TST' -Status | Sort-Object -Property Name | Select-Object -Property Name, PowerState | Format-Table -AutoSize
Solution structure:
EDIT 2: [RESOLVED] It's all fixed now, thank you! I went into the repository and mapped the folder my scripts were in directly to $(build.sourcesDirectory). Consequently I was able to change the file path to $(build.sourcesDirectory)\StartControllerAndAgents.ps1 and the build is now able to find the files to run.

Answer 1

You need to specify the path to the script as $(Build.SourcesDirectory)\Path\To\Script. Not the TFVC path which you've configured now $/Project/Path/To/Script.
The exact path depends on the workspace mapping of the build definition.
The same applies to the working directory.
There are a number of variables in Azure Pipelines (the current name for the Build hub in TFS/Azure DevOps) that resolve to different standardized paths on the agent. Almost all tasks take a relative path off of those variables.