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NUnit failed to load test assembly, test doesn't run

See original GitHub issue

When trying to run a test from Visual Studio, I sometimes see the following output, and the test doesn’t run:

[1/14/2019 1:57:48 PM Informational] ------ Run test started ------
[1/14/2019 1:57:48 PM Informational] NUnit Adapter 3.12.0.0: Test execution started
[1/14/2019 1:57:48 PM Informational] Running all tests in C:\Code\NServiceBus.Persistence.ServiceFabric\src\Tests\bin\Debug\net452\Tests.dll
[1/14/2019 1:57:48 PM Informational]    NUnit failed to load C:\Code\NServiceBus.Persistence.ServiceFabric\src\Tests\bin\Debug\net452\Tests.dll
[1/14/2019 1:57:48 PM Informational] NUnit Adapter 3.12.0.0: Test execution complete
[1/14/2019 1:57:48 PM Warning] No test matches the given testcase filter `FullyQualifiedName=ApiApproval.Approve` in C:\Code\NServiceBus.Persistence.ServiceFabric\src\Tests\bin\Debug\net452\Tests.dll
[1/14/2019 1:57:48 PM Informational] ========== Run test finished: 0 run (0:00:00.6869999) ==========

This same test runs fine on my CI server.

Is there any way to get more information about why the test assembly could not be loaded?

NUnit 3.11 NUnit3TestAdapter 3.12.0 VS 2017 15.9.5

Issue Analytics

State:
Created 5 years ago
Reactions:1
Comments:12 (9 by maintainers)

Top GitHub Comments

3reactions

gabbsmocommented, Mar 29, 2019

In my case it was Visual Studio that added and changed some dependentAssembly elements in the App.config of the test project. Undoing these changes made the tests run again.

EDIT: I could repro this by updating NUnit from Nuget. This would add System.Net.Http as a dependentAssempy. Remove this element from app.config makes the tests run again.

2reactions

bordingcommented, Jan 14, 2019

Here’s the output I’m seeing:

<?xml version="1.0" encoding="utf-8"?>
<NUnitXml>
<test-run id='2' name='Tests.dll' fullname='C:\Code\NServiceBus.Persistence.ServiceFabric\src\Tests\bin\Debug\net452\Tests.dll' testcasecount='0'>
   <test-suite type='Assembly' id='0-1000' name='Tests.dll' fullname='Tests.dll' runstate='NotRunnable' testcasecount='0'>
      <properties>
         <property name='_SKIPREASON' value='Could not load file or assembly &apos;Tests, Version=1.0.0.0, Culture=neutral, PublicKeyToken=b50674d1e0c6ce54&apos; or one of its dependencies. An attempt was made to load a program with an incorrect format.' />
      </properties>
   </test-suite>
</test-run>
</NUnitXml>

For this specific repo, that made me realize there is an x86/x64 mismatch. Once I fixed that, the test is running properly!

I have seen this in other repos which I don’t think would have the same architecture mismatch, but now I have a way to dig into why they are failing.

It would be nice if the default test adapter output could surface more detailed error information somehow without needing a runsettings file, though.

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