InternalsVisibleTo

InternalsVisibleTo

The SDK automatically generates [assembly: InternalsVisibleTo("…")] attributes for every non-test C# project. The friend assembly name is derived from the source project’s resolved $(AssemblyName), so all naming modes are handled correctly:

• Explicit <AssemblyName> — if a project sets <AssemblyName>Custom.Assembly</AssemblyName>, the generated attributes use Custom.Assembly.UnitTests, Custom.Assembly.IntegrationTests, etc.
• Default — AssemblyName is RootNamespace-derived, so fully-qualified names are used (for example Acme.MyProject.UnitTests).
• EnableAssemblyNameGeneration=false — standard .NET behaviour: $(MSBuildProjectName) (for example MyProject.UnitTests).

What is generated

Two categories of friend assemblies are generated:

1. TestType variants — for each defined TestType (Unit, Integration, Architecture, Contract, Functional, …) the SDK emits the $(AssemblyName).{TestType}Tests alias plus the $(TargetProjectName).{TestType}Tests and $(MSBuildProjectName).{TestType}Tests equivalents, so the attribute resolves regardless of whether naming comes from an explicit AssemblyName, the SDK default, or the raw project name.
2. SharedTesting projects — one per known shared testing project name (SharedTestingFramework, SharedTestingInfrastructure, etc.). By default (EnableAssemblyNameGeneration=true) with a NamespacePrefix set, these are prefixed (for example Acme.SharedTestingFramework); with EnableAssemblyNameGeneration=false the raw name is used.

InternalsVisibleTo is also generated for DynamicProxyGenAssembly2 so Moq/NSubstitute dynamic proxies can access internals.

Disabling automatic InternalsVisibleTo

To disable automatic InternalsVisibleTo generation, set DisableAutoInternalsVisibleTo=true in your project or Directory.Build.props:

<PropertyGroup>
  <DisableAutoInternalsVisibleTo>true</DisableAutoInternalsVisibleTo>
</PropertyGroup>