AssemblyInfo.cs
using System.Runtime.CompilerServices;
// Allow internal visibility for testing purposes.
[assembly: InternalsVisibleTo("Unity.TextCore")]
[assembly: InternalsVisibleTo("Unity.TextCore.FontEngine.Tools")]
[assembly: InternalsVisibleTo("Unity.FontEngine.Tests")]
[assembly: InternalsVisibleTo("Unity.TextCore.Editor")]
[assembly: InternalsVisibleTo("Unity.TextMeshPro.Editor")]