Running Unit Tests in Parallel with Azure DevOps and a Windows Agent

Microsoft has a good writeup on running unit tests in parallel with Azure DevOps and an Ubuntu build agent at https://docs.microsoft.com/en-us/azure/devops/pipelines/test/parallel-testing-any-test-runner?view=azure-devops. I had the need to do the same but with a Windows build agent. I came up with the following PowerShell script as a port of https://github.com/idubnori/ParallelTestingSample-dotnet-core/blob/master/create_slicing_filter_condition.sh.

$filterProperty="Name"
$tests = (dotnet test --no-build --list-tests) | Where-Object { $_.StartsWith("    ") } | ForEach-Object { $_.Trim() } | Get-Unique | Sort-Object
$testCount = $tests.Length
$totalAgents = $(System.TotalJobsInPhase)
$agentNumber = $(System.JobPositionInPhase)
Write-Host "Total agents: $totalAgents"
Write-Host "Agent number: $agentNumber"
Write-Host "Total tests: $testCount"
Write-Host "Target tests:"
$filter = [String]::Empty
for($i=$agentNumber; $i -le $testCount; $i = $i+$totalAgents) {
$targetTestName=$tests[$i - 1]
Write-Host "$targetTestName"
$filter = $filter + "|$filterProperty=$targetTestName"
}
$filter = $filter.TrimStart('|')
Write-Host "##vso[task.setvariable variable=targetTestsFilter]$filter";