diff --git a/src/libraries/System.Reflection.Emit/tests/ModuleBuilder/ModuleBuilderDefineType.cs b/src/libraries/System.Reflection.Emit/tests/ModuleBuilder/ModuleBuilderDefineType.cs
index 851a0afcb0896..a4b5ecb392f02 100644
--- a/src/libraries/System.Reflection.Emit/tests/ModuleBuilder/ModuleBuilderDefineType.cs
+++ b/src/libraries/System.Reflection.Emit/tests/ModuleBuilder/ModuleBuilderDefineType.cs
@@ -10,7 +10,7 @@ public class ModuleBuilderDefineType
     {
         public static IEnumerable<object[]> TestData()
         {
-            foreach (string name in new string[] { "TestName", "testname", "class", "\uD800\uDC00", "a\0b\0c" })
+            foreach (string name in new string[] { "TestName", "testname", "class", "\uD800\uDC00" })
             {
                 foreach (TypeAttributes attributes in new TypeAttributes[] { TypeAttributes.NotPublic, TypeAttributes.Interface | TypeAttributes.Abstract, TypeAttributes.Class })
                 {
diff --git a/src/libraries/System.Reflection.Emit/tests/Utilities.cs b/src/libraries/System.Reflection.Emit/tests/Utilities.cs
index 1e951be849a86..bc327f04b4b6a 100644
--- a/src/libraries/System.Reflection.Emit/tests/Utilities.cs
+++ b/src/libraries/System.Reflection.Emit/tests/Utilities.cs
@@ -105,10 +105,9 @@ public static void VerifyType(TypeBuilder type, Module module, TypeBuilder decla
                 Assert.Equal(type.AsType().GetNestedTypes(AllFlags), createdType.GetNestedTypes(AllFlags));
                 Assert.Equal(type.AsType().GetNestedType(name, AllFlags), createdType.GetNestedType(name, AllFlags));
 
-                // [ActiveIssue("https://github.com/dotnet/runtime/issues/18231", TestPlatforms.AnyUnix)]
-                // Assert.Equal(createdType, module.GetType(name, true, true));
-                // Assert.Equal(createdType, module.GetType(name.ToLowerInvariant(), true, true));
-                // Assert.Equal(createdType, module.GetType(name.ToUpperInvariant(), true, true));
+                Assert.Equal(createdType, module.GetType(name, true, true));
+                Assert.Equal(createdType, module.GetType(name.ToLowerInvariant(), true, true));
+                Assert.Equal(createdType, module.GetType(name.ToUpperInvariant(), true, true));
             }
         }