Add tests to enforcement test framework rules and conventions.

* Add a unit test to verify a type can be found for every test case cs file.

* Add a test to verify that the Expectations assembly only contains types used for annotating test cases and is not used as a home for common test case helper code.

* Move `TestSystemTypeBase` to the test cases assembly.  This is helper code and should not be in the Expectations assembly.

3 files changed, 169 insertions, 0 deletions

diff --git a/test/Mono.Linker.Tests.Cases/DataFlow/Dependencies/TestSystemTypeBase.cs b/test/Mono.Linker.Tests.Cases/DataFlow/Dependencies/TestSystemTypeBase.cs
new file mode 100644
index 000000000..c1a90a423
--- /dev/null
+++ b/test/Mono.Linker.Tests.Cases/DataFlow/Dependencies/TestSystemTypeBase.cs
@@ -0,0 +1,165 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Globalization;
+using System.Reflection;
+
+namespace System
+{
+	public class TestSystemTypeBase : Type
+	{
+		public override Assembly Assembly => throw new NotImplementedException ();
+
+		public override string AssemblyQualifiedName => throw new NotImplementedException ();
+
+		public override Type BaseType => throw new NotImplementedException ();
+
+		public override string FullName => throw new NotImplementedException ();
+
+		public override Guid GUID => throw new NotImplementedException ();
+
+		public override Module Module => throw new NotImplementedException ();
+
+		public override string Namespace => throw new NotImplementedException ();
+
+		public override Type UnderlyingSystemType => throw new NotImplementedException ();
+
+		public override string Name => throw new NotImplementedException ();
+
+		public override ConstructorInfo[] GetConstructors (BindingFlags bindingAttr)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override object[] GetCustomAttributes (bool inherit)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override object[] GetCustomAttributes (Type attributeType, bool inherit)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override Type GetElementType ()
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override EventInfo GetEvent (string name, BindingFlags bindingAttr)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override EventInfo[] GetEvents (BindingFlags bindingAttr)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override FieldInfo GetField (string name, BindingFlags bindingAttr)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override FieldInfo[] GetFields (BindingFlags bindingAttr)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override Type GetInterface (string name, bool ignoreCase)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override Type[] GetInterfaces ()
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override MemberInfo[] GetMembers (BindingFlags bindingAttr)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override MethodInfo[] GetMethods (BindingFlags bindingAttr)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override Type GetNestedType (string name, BindingFlags bindingAttr)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override Type[] GetNestedTypes (BindingFlags bindingAttr)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override PropertyInfo[] GetProperties (BindingFlags bindingAttr)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override object InvokeMember (string name, BindingFlags invokeAttr, Binder binder, object target, object[] args, ParameterModifier[] modifiers, CultureInfo culture, string[] namedParameters)
+		{
+			throw new NotImplementedException ();
+		}
+
+		public override bool IsDefined (Type attributeType, bool inherit)
+		{
+			throw new NotImplementedException ();
+		}
+
+		protected override TypeAttributes GetAttributeFlagsImpl ()
+		{
+			throw new NotImplementedException ();
+		}
+
+		protected override ConstructorInfo GetConstructorImpl (BindingFlags bindingAttr, Binder binder, CallingConventions callConvention, Type[] types, ParameterModifier[] modifiers)
+		{
+			throw new NotImplementedException ();
+		}
+
+		protected override MethodInfo GetMethodImpl (string name, BindingFlags bindingAttr, Binder binder, CallingConventions callConvention, Type[] types, ParameterModifier[] modifiers)
+		{
+			throw new NotImplementedException ();
+		}
+
+		protected override PropertyInfo GetPropertyImpl (string name, BindingFlags bindingAttr, Binder binder, Type returnType, Type[] types, ParameterModifier[] modifiers)
+		{
+			throw new NotImplementedException ();
+		}
+
+		protected override bool HasElementTypeImpl ()
+		{
+			throw new NotImplementedException ();
+		}
+
+		protected override bool IsArrayImpl ()
+		{
+			throw new NotImplementedException ();
+		}
+
+		protected override bool IsByRefImpl ()
+		{
+			throw new NotImplementedException ();
+		}
+
+		protected override bool IsCOMObjectImpl ()
+		{
+			throw new NotImplementedException ();
+		}
+
+		protected override bool IsPointerImpl ()
+		{
+			throw new NotImplementedException ();
+		}
+
+		protected override bool IsPrimitiveImpl ()
+		{
+			throw new NotImplementedException ();
+		}
+	}
+}
\ No newline at end of file
diff --git a/test/Mono.Linker.Tests.Cases/DataFlow/MethodThisDataFlow.cs b/test/Mono.Linker.Tests.Cases/DataFlow/MethodThisDataFlow.cs
index e04fb56e1..3a8fbe1ef 100644
--- a/test/Mono.Linker.Tests.Cases/DataFlow/MethodThisDataFlow.cs
+++ b/test/Mono.Linker.Tests.Cases/DataFlow/MethodThisDataFlow.cs
@@ -9,10 +9,12 @@ using System.Globalization;
 using System.Reflection;
 using System.Text;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Metadata;
 
 namespace Mono.Linker.Tests.Cases.DataFlow
 {
 	[SkipKeptItemsValidation]
+	[SandboxDependency ("Dependencies/TestSystemTypeBase.cs")]
 	public class MethodThisDataFlow
 	{
 		public static void Main ()
diff --git a/test/Mono.Linker.Tests.Cases/DataFlow/VirtualMethodHierarchyDataflowAnnotationValidation.cs b/test/Mono.Linker.Tests.Cases/DataFlow/VirtualMethodHierarchyDataflowAnnotationValidation.cs
index d28d2c815..46801b241 100644
--- a/test/Mono.Linker.Tests.Cases/DataFlow/VirtualMethodHierarchyDataflowAnnotationValidation.cs
+++ b/test/Mono.Linker.Tests.Cases/DataFlow/VirtualMethodHierarchyDataflowAnnotationValidation.cs
@@ -7,10 +7,12 @@ using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Text;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Metadata;
 
 namespace Mono.Linker.Tests.Cases.DataFlow
 {
 	[SkipKeptItemsValidation]
+	[SandboxDependency ("Dependencies/TestSystemTypeBase.cs")]
 	class VirtualMethodHierarchyDataflowAnnotationValidation
 	{
 		public static void Main ()