<PackageReference Include="NUnit" Version="4.3.2" />

NonTestAssemblyAttribute

Used by third-party frameworks, or other software, that reference the NUnit framework but do not contain any tests. Applying the attribute indicates that the assembly is not a test assembly and may prevent errors if certain runners attempt to load the assembly. Note that recognition of the attribute depends on each individual runner.
using System; using System.ComponentModel; namespace NUnit.Framework { [EditorBrowsable(EditorBrowsableState.Never)] [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = false, Inherited = false)] public class NonTestAssemblyAttribute : NUnitAttribute { } }