Unable to write unit tests without adding refernece to the source generator

[ByronMayne]

Description:
Unable to write unit test for source generators due to a FileNotFoundException. The exception is being thrown because the unit test project is unable to locate SourceGenerator.Foundations.Contracts.dll. The current problem is that the only way to get this reference is to add the NuGet package <PackageReference Include="SourceGenerator.Foundations" Version="2.0.4" />. The issue is then the unit tests project won't build because it's not in fact a source generator.

 AutoFactories.Tests.DiagnosticsTests.UntaggedClass
   Source: DiagnosticsTests.cs line 19
   Duration: 711 ms

  Message: 
System.IO.FileNotFoundException : Could not load file or assembly 'SourceGenerator.Foundations.Contracts, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.

  Stack Trace: 
AbstractTest.Compose(String source, Boolean verifyOutput, Action`1 assertDiagnostics)
AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
AbstractTest.Compose(String source, Boolean verifyOutput, Action`1 assertDiagnostics)
DiagnosticsTests.UntaggedClass() line 20
RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)

Solution:
Create a publish just the contracts library by itself so unit tests can reference that and still compile.