TFS2015 503 service unavailable using .runsetting unit test file - unit-testing

Question

In short, using a .runsetting unit test file in a build step on TFS 2015 results in a 503 Service Unavailable exception.
After extensive searching and testing on a new TFS 2015 installation (as also described in TFS2015 new install, 503 Service Unavailable), I may have found the problem.
We are using .runsettings files as described on https://msdn.microsoft.com/en-us/library/jj159530.aspx, in a 'Visual Studio Test' build step on our new TFS2015 installation, as soon as the VSTest.console.exe is called, the next three application pools on the TFS server crash, resulting in a 503 Service Unavailable error:
DefaultAppPool
Microsoft Team Foundation Server Application Pool
Microsoft Team Foundation SErver Message Queueu Application Pool
First my .runsetting file was kind of large, but i did try the next one (I think as small as possible):
<?xml version="1.0" encoding="utf-8"?>
<RunSettings>
<!-- Configurations for data collectors -->
<DataCollectionRunSettings>
<DataCollectors>
<DataCollector friendlyName="Code Coverage" uri="datacollector://Microsoft/CodeCoverage/2.0" assemblyQualifiedName="Microsoft.VisualStudio.Coverage.DynamicCoverageDataCollector, Microsoft.VisualStudio.TraceCollector, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
<Configuration>
<CodeCoverage>
<!-- Match assembly file paths: -->
<ModulePaths>
<Include>
<ModulePath>.*\.dll$</ModulePath>
<ModulePath>.*\.exe$</ModulePath>
</Include>
<Exclude>
<ModulePath>.*CPPUnitTestFramework.*</ModulePath>
<ModulePath>.*fluentassertions.*</ModulePath>
<ModulePath>.*\.test\.dll$</ModulePath>
</Exclude>
</ModulePaths>
</CodeCoverage>
</Configuration>
</DataCollector>
</DataCollectors>
</DataCollectionRunSettings>
</RunSettings>
When using this one, the app pools crashes. Even if i remove the part entirely, it will not work.
As soon as the next line is called (taken from the log lines of the build step), the app pools crashes.
Executing C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\CommonExtensions\Microsoft\TestWindow\vstest.console.exe "D:\TfsAgents\Agent1\_work\2\s\[...]\Release\Microsoft.QualityTools.Testing.Fakes.dll" "D:\TfsAgents\Agent1\_work\2\s\[...]\Release\Microsoft.VisualStudio.QualityTools.UnitTestFramework.dll" "D:\TfsAgents\Agent1\_work\2\s\[...]\Release\MyClassLib.dll" /Settings:"D:\TfsAgents\Agent1\_work\2\s\[...]\test.runsettings" /EnableCodeCoverage /logger:trx
If you look at the DataCollector tag in the .runsettings file, you see the version is set to 14.0.0.0. If you look at the page of Miscrosoft, they state that it should be 11.0.0.0, but also this version does not work. I thought it might be that version 11.0.0.0 was wrong, so I opened the dll with Telerik JustDecompile, and saw that the 'real' version was 14.0.0.0, so I put that version into the runsetting-file. But no luck.
So for now I'm just remove the runsetting file from the definition of the build, which unfortunately results in a wrong code coverate percentage.. So hopefully someone might have the answer for this.

Answer 1

This problem is limited to the specific runsettings file when used with build agent running on the same machine where IIS server is hosting TFS. There is a workaround available. Within DataCollectors->Configuration->CodeCoverage tag in runsettings file you can add following xml tags with given values :
<UseVerifiableInstrumentation>True</UseVerifiableInstrumentation>
<AllowLowIntegrityProcesses>True</AllowLowIntegrityProcesses>
<CollectFromChildProcesses>True</CollectFromChildProcesses>
<CollectAspDotNet>false</CollectAspDotNet>
This should solve the issue, and also its recommended that in future if you are using runsettings file with Code coverage in Data Collector then these tags should be added.