Only working with Nunit < version 3

[aswhitehouse]

Running this on a mac with Mono 4 / Docker / .net core + .net framework.

No troubles running the container and seems to read & parse most assemblies that I load into it's volume at run time however assemblies with tests built on version 3 or greater of Nunit fail with,

Unhandled Exception:
�NUnit.Core.UnsupportedFrameworkException: Skipped loading assembly Foo because it references an unsupported version of the nunit.framework, 3.5.0.0

Server stack trace: 
�  at NUnit.Core.Builders.TestAssemblyBuilder.GetCandidateFixtureTypes (System.Reflection.Assembly assembly, System.String ns) [0x00000] in <filename unknown>:0 
�  at NUnit.Core.Builders.TestAssemblyBuilder.GetFixtures (System.Reflection.Assembly assembly, System.String ns) [0x00000] in <filename unknown>:0 
�  at NUnit.Core.Builders.TestAssemblyBuilder.Build (System.String assemblyName, Boolean autoSuites) [0x00000] in <filename unknown>:0 
�  at NUnit.Core.Builders.TestAssemblyBuilder.Build (System.String assemblyName, System.String testName, Boolean autoSuites) [0x00000] in <filename unknown>:0 
y  at NUnit.Core.TestSuiteBuilder.BuildSingleAssembly (NUnit.Core.TestPackage package) [0x00000] in <filename unknown>:0 
k  at NUnit.Core.TestSuiteBuilder.Build (NUnit.Core.TestPackage package) [0x00000] in <filename unknown>:0 
j  at NUnit.Core.SimpleTestRunner.Load (NUnit.Core.TestPackage package) [0x00000] in <filename unknown>:0 
i  at NUnit.Core.ProxyTestRunner.Load (NUnit.Core.TestPackage package) [0x00000] in <filename unknown>:0 
i  at NUnit.Core.ProxyTestRunner.Load (NUnit.Core.TestPackage package) [0x00000] in <filename unknown>:0 
j  at NUnit.Core.RemoteTestRunner.Load (NUnit.Core.TestPackage package) [0x00000] in <filename unknown>:0 
Z  at (wrapper xdomain-dispatch) NUnit.Core.RemoteTestRunner:Load (object,byte[]&,byte[]&)

Exception rethrown at [0]: 

X  at (wrapper xdomain-invoke) NUnit.Core.RemoteTestRunner:Load (NUnit.Core.TestPackage)
d  at NUnit.Util.TestDomain.Load (NUnit.Core.TestPackage package) [0x00000] in <filename unknown>:0 

Assemblies with tests < version 3 work great.

Any ideas, am I missing something or does it just not support Nunit 3?

Cheers.