Troubleshooting

MSBuild integration

Generate verbose log

dotnet test test\coverlet.core.tests\coverlet.core.tests.csproj -c debug /p:CollectCoverage=true /p:CoverletOutputFormat=opencover /p:Include=[coverlet.*]* -verbosity:diagnostic -bl:msbuild.binlog -noconsolelogger

Download http://msbuildlog.com/
Open msbuild.binlog generated and search for '[coverlet]' logs

Collectors integration

dotnet test --collect:"XPlat Code Coverage" --settings runsettings --diag:log.txt

You'll get logs file in same folder similar to

log.datacollector.19-09-12_14-55-17_64755_5.txt
log.host.19-09-12_14-55-18_82700_6.txt
log.txt

Search inside with filter '[coverlet]'

Coverlet Global Tool

coverlet "C:\git\coverlet\test\coverlet.core.tests\bin\Debug\net6.0\coverlet.core.tests.dll" --target "dotnet" --targetargs "test C:\git\coverlet\test\coverlet.core.tests --no-build" --verbosity detailed

Sample output

...
Instrumented module: 'C:\git\coverlet\test\coverlet.core.tests\bin\Debug\net6.0\coverlet.core.dll'
Instrumented module: 'C:\git\coverlet\test\coverlet.core.tests\bin\Debug\net6.0\xunit.runner.reporters.netcoreapp10.dll'
Instrumented module: 'C:\git\coverlet\test\coverlet.core.tests\bin\Debug\net6.0\xunit.runner.utility.netcoreapp10.dll'
Instrumented module: 'C:\git\coverlet\test\coverlet.core.tests\bin\Debug\net6.0\xunit.runner.visualstudio.dotnetcore.testadapter.dll'
Test run for C:\git\coverlet\test\coverlet.core.tests\bin\Debug\net6.0\coverlet.core.tests.dll(.NETCoreApp,Version=v2.0)
Microsoft (R) Test Execution Command Line Tool Version 16.0.1
Copyright (c) Microsoft Corporation.  All rights reserved.
Starting test execution, please wait...
[xUnit.net 00:00:01.4218329]     Coverlet.Core.Tests.Instrumentation.ModuleTrackerTemplateTests.HitsOnMultipleThreadsCorrectlyCounted [SKIP]
Skipped  Coverlet.Core.Tests.Instrumentation.ModuleTrackerTemplateTests.HitsOnMultipleThreadsCorrectlyCounted
[xUnit.net 00:00:03.6302618]     Coverlet.Core.Instrumentation.Tests.InstrumenterTests.TestCoreLibInstrumentation [SKIP]
Skipped  Coverlet.Core.Instrumentation.Tests.InstrumenterTests.TestCoreLibInstrumentation
Total tests: 113. Passed: 111. Failed: 0. Skipped: 2.
Test Run Successful.
Test execution time: 4,6411 Seconds

Calculating coverage result...
Hits file:'C:\Users\Marco\AppData\Local\Temp\coverlet.core_703263e9-21f0-4d1c-9ce3-98ddeacecc01' not found for module: 'coverlet.core'
  Generating report 'C:\git\coverlet\src\coverlet.console\bin\Debug\net6.0\coverage.json'
+--------------------------------------------------+--------+--------+--------+
| Module                                           | Line   | Branch | Method |
+--------------------------------------------------+--------+--------+--------+
| coverlet.core                                    | 0%     | 0%     | 0%     |
+--------------------------------------------------+--------+--------+--------+
| xunit.runner.reporters.netcoreapp10              | 2,11%  | 0,83%  | 8,88%  |
+--------------------------------------------------+--------+--------+--------+
| xunit.runner.utility.netcoreapp10                | 12,06% | 6,6%   | 17,09% |
+--------------------------------------------------+--------+--------+--------+
| xunit.runner.visualstudio.dotnetcore.testadapter | 50,04% | 42,08% | 50,9%  |
+--------------------------------------------------+--------+--------+--------+

+---------+--------+--------+--------+
|         | Line   | Branch | Method |
+---------+--------+--------+--------+
| Total   | 17,76% | 13,82% | 22,64% |
+---------+--------+--------+--------+
| Average | 4,44%  | 3,455% | 5,66%  |
+---------+--------+--------+--------+

Use local build (no collectors)

Sometimes is useful test local updated source to fix issue. You can "load" your local build using simple switch:

build repo

D:\git\coverlet (fixjsonserializerbug -> origin)
λ dotnet build
Microsoft (R) Build Engine version 16.1.76+g14b0a930a7 for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

Restore completed in 52.23 ms for D:\git\coverlet\test\coverlet.testsubject\coverlet.testsubject.csproj.
Restore completed in 58.97 ms for D:\git\coverlet\src\coverlet.console\coverlet.console.csproj.
Restore completed in 59 ms for D:\git\coverlet\src\coverlet.core\coverlet.core.csproj.
Restore completed in 59.17 ms for D:\git\coverlet\src\coverlet.msbuild.tasks\coverlet.msbuild.tasks.csproj.
Restore completed in 59.26 ms for D:\git\coverlet\src\coverlet.collector\coverlet.collector.csproj.
Restore completed in 60.1 ms for D:\git\coverlet\test\coverlet.collector.tests\coverlet.collector.tests.csproj.
Restore completed in 60.42 ms for D:\git\coverlet\test\coverlet.core.performancetest\coverlet.core.performancetest.csproj.
Restore completed in 60.47 ms for D:\git\coverlet\test\coverlet.core.tests\coverlet.core.tests.csproj.
Restore completed in 22.85 ms for D:\git\coverlet\test\coverlet.core.tests\coverlet.core.tests.csproj.
coverlet.testsubject -> D:\git\coverlet\test\coverlet.testsubject\bin\Debug\net6.0\coverlet.testsubject.dll
coverlet.core -> D:\git\coverlet\src\coverlet.core\bin\Debug\netstandard2.0\coverlet.core.dll
coverlet.msbuild.tasks -> D:\git\coverlet\src\coverlet.msbuild.tasks\bin\Debug\netstandard2.0\coverlet.msbuild.tasks.dll
coverlet.collector -> D:\git\coverlet\src\coverlet.collector\bin\Debug\net6.0\coverlet.collector.dll
coverlet.console -> D:\git\coverlet\src\coverlet.console\bin\Debug\net6.0\coverlet.console.dll
coverlet.core.performancetest -> D:\git\coverlet\test\coverlet.core.performancetest\bin\Debug\net6.0\coverlet.core.performancetest.dll
coverlet.core.tests -> D:\git\coverlet\test\coverlet.core.tests\bin\Debug\net6.0\coverlet.core.tests.dll
coverlet.collector.tests -> D:\git\coverlet\test\coverlet.collector.tests\bin\Debug\net6.0\coverlet.collector.tests.dll

Build succeeded.
    0 Warning(s)
    0 Error(s)

Time Elapsed 00:00:07.42

D:\git\coverlet (fixjsonserializerbug -> origin)

Go to repro project and run

D:\git\Cake.Codecov\Source\Cake.Codecov.Tests (develop -> origin)
λ dotnet test /p:CollectCoverage=true /p:Exclude="[xunit.*]*" /p:CoverletToolsPath=D:\git\coverlet\src\coverlet.msbuild.tasks\bin\Debug\netstandard2.0\
Test run for D:\git\Cake.Codecov\Source\Cake.Codecov.Tests\bin\Debug\netcoreapp2.0\Cake.Codecov.Tests.dll(.NETCoreApp,Version=v2.0)
...

In this way you can add Debug.Launch() inside coverlet source and debug.

Use local collectors build

To use/debug local collectors build we need to tell to our project to restore and use our local build nuget package.

Build local package

C:\git\coverlet\src\coverlet.collector (master -> origin)
λ dotnet pack
Microsoft (R) Build Engine version 16.2.32702+c4012a063 for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

Restore completed in 50,28 ms for C:\git\coverlet\src\coverlet.collector\coverlet.collector.csproj.
Restore completed in 50,28 ms for C:\git\coverlet\src\coverlet.core\coverlet.core.csproj.
coverlet.core -> C:\git\coverlet\src\coverlet.core\bin\Debug\netstandard2.0\coverlet.core.dll
coverlet.collector -> C:\git\coverlet\src\coverlet.collector\bin\Debug\netcoreapp2.0\coverlet.collector.dll
Successfully created package 'C:\git\coverlet\bin\Debug\Packages\coverlet.collector.1.0.67.nupkg'.
Successfully created package 'C:\git\coverlet\bin\Debug\Packages\coverlet.collector.1.0.67.snupkg'.

Add new NuGet.Config file on your test project/solution

<?xml version="1.0" encoding="utf-8"?>
<configuration>
<packageSources>
    <clear />
    <!-- Local path where you build packages -->
    <add key="localpackagesbuild" value="C:\git\coverlet\bin\Debug\Packages" />
    <!-- Defaul nuget feed -->
    <add key="nuget" value="https://api.nuget.org/v3/index.json" />
    <!-- Add all other needed feed -->
</packageSources>
</configuration>

Update nuget package in our test project

<Project Sdk="Microsoft.NET.Sdk">

<PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <IsPackable>false</IsPackable>
</PropertyGroup>

<ItemGroup>
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
    <PackageReference Include="xunit" Version="2.6.5" />
    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.6" />
    <PackageReference Include="coverlet.collector" Version="6.0.0" /> <-- My local package version -->
</ItemGroup>

<ItemGroup>
    <ProjectReference Include="..\ClassLibrary1\ClassLibrary1.csproj" />
</ItemGroup>

</Project>

Run test command

dotnet test XUnitTestProject1\ --collect:"XPlat Code Coverage"

You can also attach/debug your code adding some line of code on collectors i.e.

Attach using vs "Attach to Process"

while(!System.Diagnostics.Debugger.IsAttached)
{
    System.Threading.Thread.Sleep(1000);
}

Fire attach

System.Diagnostics.Debugger.Launch();

If you want debug in-process collector, you need to set VSTEST_HOST_DEBUG environment variable

set VSTEST_HOST_DEBUG=1

Test host will wait for debugger

Starting test execution, please wait...
Logging Vstest Diagnostics in file: C:\git\coverletissue\collectorlog\XUnitTestProject1\log.txt
Host debugging is enabled. Please attach debugger to testhost process to continue.
Process Id: 800, Name: dotnet

Every time you update code and rebuild new package, remember to remove local nuget cache (RMDIR "C:\Users\[winUser]\.nuget\packages\coverlet.collector" /S /Q) otherwise you'll load old collector code because the package version wasn't changed

Enable injected tracker log

Coverlet works thanks to ModuleTracker that is injected during instrumentation for every covered module. This piece of code is run as a part of tests and doesn't have any connection with Coverlet.

We can collect logs from trackers through an enviroment variable

 set COVERLET_ENABLETRACKERLOG=1

When enabled, tracking event will be collected in a log file near to module location. File name will be something like moduleName.dll_tracker.txt and files with detailed hits will be in a folder named TrackersHitsLog.

Enable msbuild task instrumentation debugging

You can live attach and debug msbuild tasks with COVERLET_MSBUILD_INSTRUMENTATIONTASK_DEBUG env variable

 set COVERLET_MSBUILD_INSTRUMENTATIONTASK_DEBUG=1

Enable collector instrumentation debugging

You can live attach and debug collectors with COVERLET_DATACOLLECTOR_OUTOFPROC_DEBUG and COVERLET_DATACOLLECTOR_INPROC_DEBUG env variable

 set COVERLET_DATACOLLECTOR_OUTOFPROC_DEBUG=1
 set COVERLET_DATACOLLECTOR_INPROC_DEBUG=1

You will be asked to attach a debugger through UI popup. To enable exceptions log for in-process data collectors

 set COVERLET_DATACOLLECTOR_INPROC_EXCEPTIONLOG_ENABLED=1

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Troubleshooting.md

Troubleshooting.md

Troubleshooting

MSBuild integration

Collectors integration

Coverlet Global Tool

Use local build (no collectors)

Use local collectors build

Enable injected tracker log

Enable msbuild task instrumentation debugging

Enable collector instrumentation debugging

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Troubleshooting.md

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Troubleshooting.md

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Troubleshooting

MSBuild integration

Collectors integration

Coverlet Global Tool

Use local build (no collectors)

Use local collectors build

Enable injected tracker log

Enable msbuild task instrumentation debugging

Enable collector instrumentation debugging