NUnit 4.2.0 is missing System.Buffers on .NET Framework

[ghelyar]

Upgrading from NUnit 4.1.0 to 4.2.0 in a .NET Framework project causes a System.IO.FileNotFoundException of System.Buffers at runtime, when asserting equality on any type after the StreamsComparer in the list, including enums, chars, etc.

It looks like it's because while it goes through the comparers it's trying to use a StreamsComparer, which was changed to use System.Buffers here, but this probably needs a package reference for .NET Framework.

In fact at the time that had

#if !NETFRAMEWORK
using System.Buffers;
#endif

but that got removed here.

Error:

System.IO.FileNotFoundException : Could not load file or assembly 'System.Buffers, Version=4.0.3.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file specified.
   at NUnit.Framework.Constraints.Comparers.StreamsComparer.Equal(Object x, Object y, Tolerance& tolerance, ComparisonState state, NUnitEqualityComparer equalityComparer)
   at NUnit.Framework.Constraints.NUnitEqualityComparer.AreEqual(Object x, Object y, Tolerance& tolerance, ComparisonState state)
   at NUnit.Framework.Constraints.NUnitEqualityComparer.AreEqual(Object x, Object y, Tolerance& tolerance)
   at NUnit.Framework.Constraints.EqualConstraint.ApplyTo[TActual](TActual actual)
   at NUnit.Framework.Assert.That[TActual](TActual actual, IResolveConstraint expression, NUnitString message, String actualExpression, String constraintExpression)
   at nurepro.Repro.Test()

Repro:

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

  <PropertyGroup>
    <TargetFramework>net48</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.0" />
    <PackageReference Include="NUnit" Version="4.2.0" />
    <PackageReference Include="NUnit3TestAdapter" Version="4.6.0">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
  </ItemGroup>

</Project>

using NUnit.Framework;

namespace nurepro
{
    public class Repro
    {
        [Test]
        public void TestEnum()
        {
            Assert.That(Foo.Bar, Is.EqualTo(Foo.Bar));
        }
        
        [Test]
        public void TestChar()
        {        
            Assert.That('x', Is.EqualTo('x'));
        }
    }

    public enum Foo
    {
        Bar = 1,
    }
}

[OsirisTerje]

Thanks!
Same as #4794

We're working on a fix, by adding in System.Memory as a dependency in the package nuspec. System.Memory depends on System.Buffers, so that should solve it.

Adding your code to the repro at https://github.com/nunit/nunit.issues/tree/main/Issue4794

In the meantime, workaround is to add a reference to System.Memory (Or only Buffers) in your test code. We will try to get the fix out today, during the weekend at latest.

[OsirisTerje]

@ghelyar Can you verify that the enclosed package works for you:
NUnit.4.2.1.zip

[OsirisTerje]

Version 4.2.1 is released on Github and on Nuget.

[ghelyar]

4.2.1 fixes the issue.

[OsirisTerje]

Thanks @ghelyar !