diff --git a/ClosedXML_Tests/Excel/CalcEngine/LookupTests.cs b/ClosedXML_Tests/Excel/CalcEngine/LookupTests.cs
index 6938b37..babfab0 100644
--- a/ClosedXML_Tests/Excel/CalcEngine/LookupTests.cs
+++ b/ClosedXML_Tests/Excel/CalcEngine/LookupTests.cs
@@ -17,6 +17,12 @@
             workbook = SetupWorkbook();
         }
 
+        [OneTimeTearDown]
+        public void Dispose()
+        {
+            workbook.Dispose();
+        }
+
         private XLWorkbook SetupWorkbook()
         {
             var wb = new XLWorkbook();