diff --git a/Snowflake.Data.Tests/UnitTests/SFDataConverterTest.cs b/Snowflake.Data.Tests/UnitTests/SFDataConverterTest.cs
index fc2e8b274..181b0b87a 100755
--- a/Snowflake.Data.Tests/UnitTests/SFDataConverterTest.cs
+++ b/Snowflake.Data.Tests/UnitTests/SFDataConverterTest.cs
@@ -339,8 +339,12 @@ public void TestInvalidTimestampConversion(SFDataType dataType, Type unsupported
             object unsupportedObject;
             if (unsupportedType == typeof(DateTimeOffset))
                 unsupportedObject = new DateTimeOffset();
-            else
+            else if (unsupportedType == typeof(DateTime))
                 unsupportedObject = new DateTime();
+            else
+                unsupportedObject = null;
+
+            Assert.NotNull(unsupportedType);
             SnowflakeDbException ex = Assert.Throws<SnowflakeDbException>(() => SFDataConverter.csharpValToSfVal(dataType, unsupportedObject));
             SnowflakeDbExceptionAssert.HasErrorCode(ex, SFError.INVALID_DATA_CONVERSION);
         }