Set "Path" environment variable during vsts build so it would persist across build tasks specifically vsTest task

Set the process environment variable by calling logging command through PowerShell task:

For example:

Write-Host "##vso[task.setvariable variable=PATH;]${env:PATH};$newPath";

If you need to do this in a Linux pipeline you can do the following:

- script: echo "##vso[task.setvariable variable=PATH]${PATH}:<your new path here>"