diff --git a/tests/NodaTimeSplitterTest.php b/tests/NodaTimeSplitterTest.php
index d9fdd51..0d1d0fa 100644
--- a/tests/NodaTimeSplitterTest.php
+++ b/tests/NodaTimeSplitterTest.php
@@ -1372,14 +1372,16 @@ final class NodaTimeSplitterTest extends TestCase {
 
         $output = NodaTimeSplitter::attempt_splitting("20th century");
         self::assertNotEmpty($output);
-        self::assertEquals($output->toOldFormat(), [
-            0 => "1901",
-            1 => "2000",
-            2 => "00",
-            3 => "00",
-            4 => "+",
-            5 => "",
-        ]);
+        if ($output !== false) {
+            self::assertEquals($output->toOldFormat(), [
+                0 => "1901",
+                1 => "2000",
+                2 => "00",
+                3 => "00",
+                4 => "+",
+                5 => "",
+            ]);
+        }
         self::assertEquals($output->toTimeName(), "1901-2000");
         self::assertEquals(NodaTimeSplitter::timePartsToCountingYear($output), 1951);