diff --git a/src/Lucene.Net.Tests.Analysis.Common/Analysis/Util/TestFilesystemResourceLoader.cs b/src/Lucene.Net.Tests.Analysis.Common/Analysis/Util/TestFilesystemResourceLoader.cs
index 06db2c28ef..0b5b794f9f 100644
--- a/src/Lucene.Net.Tests.Analysis.Common/Analysis/Util/TestFilesystemResourceLoader.cs
+++ b/src/Lucene.Net.Tests.Analysis.Common/Analysis/Util/TestFilesystemResourceLoader.cs
@@ -116,8 +116,8 @@ public virtual void TestBaseDir()
         [Test]
         public virtual void TestDelegation()
         {
-            IResourceLoader rl = new FilesystemResourceLoader(null, new StringMockResourceLoader("foobar\n"));
+            IResourceLoader rl = new FilesystemResourceLoader((string)null, new StringMockResourceLoader("foobar\n"));
             assertEquals("foobar", WordlistLoader.GetLines(rl.OpenResource("template.txt"), Encoding.UTF8).First());
         }
     }
-}
\ No newline at end of file
+}