diff --git a/src/test/java/com/fasterxml/jackson/core/format/TestJsonFormatDetection.java b/src/test/java/com/fasterxml/jackson/core/format/TestJsonFormatDetection.java
index 62be718989..bc133eada2 100644
--- a/src/test/java/com/fasterxml/jackson/core/format/TestJsonFormatDetection.java
+++ b/src/test/java/com/fasterxml/jackson/core/format/TestJsonFormatDetection.java
@@ -83,6 +83,7 @@ public void testSimpleInvalid() throws Exception
         DataFormatMatcher matcher = detector.findFormat(new ByteArrayInputStream(NON_JSON.getBytes("UTF-8")));
         // should not have match
         assertFalse(matcher.hasMatch());
+        assertNull(matcher.getMatchedFormatName());
         // and thus:
         assertEquals(MatchStrength.INCONCLUSIVE, matcher.getMatchStrength());
         // also: