I have a below VsTest task in my azure pipeline. It runs more than 5 thousand tests. Does someone knows what exactly the ‘customBatchSizeValue’ means ? I know the tests are grouped as batches, each containing 800 test cases and for every batch, it generates a separate trx file and a test run. My question is: do the 800 test cases in every batch run parallelly as well ? How does it changes when tests are UI & non-UI ?

I already referred this MS doc on VsTest, but doesn’t seem to be detailed. https://learn.microsoft.com/en-us/azure/devops/pipelines/tasks/reference/vstest-v2?view=azure-pipelines

- task: VSTest@2
  displayName: 'Run UI tests'
  inputs:
    testAssemblyVer2: '**UITest.dll'
    searchFolder: '$(TargetDir)UITest'
    vsTestVersion: toolsInstaller
    runSettingsFile: '$(TargetDir)UITest.pipeline.runsettings'
    pathtoCustomTestAdapters: 'C:TempTestAdapter'
    runTestsInIsolation: false
    batchingBasedOnAgentsOption: customBatchSize
    customBatchSizeValue: 800
    testRunTitle: 'UITest from Directory (1)'
    platform: x64
    failOnMinTestsNotRun: true
    rerunFailedTests: true
  continueOnError: true
  timeoutInMinutes: 180