diff --git a/tests/OpenUrzednik.Core.Tests/Exceptions/OpenUrzednikValidationExceptionTest.cs b/tests/OpenUrzednik.Core.Tests/Exceptions/OpenUrzednikValidationExceptionTest.cs
index b4a4231..393bc14 100644
--- a/tests/OpenUrzednik.Core.Tests/Exceptions/OpenUrzednikValidationExceptionTest.cs
+++ b/tests/OpenUrzednik.Core.Tests/Exceptions/OpenUrzednikValidationExceptionTest.cs
@@ -52,7 +52,7 @@ public void Ctor_NoErrors_ThrowsArgumentException()
     public void Ctor_NullErrors_ThrowsArgumentNullException()
     {
         // Act && Assert
-        Should.Throw<ArgumentNullException>(() => new OpenUrzednikValidationException((IReadOnlyList<ValidationError>)null!));
+        Should.Throw<ArgumentNullException>(() => new OpenUrzednikValidationException(null!));
     }
 
     [Fact]