diff --git a/fints4k/src/jvmTest/kotlin/net/codinux/banking/fints/response/ResponseParserTestJvm.kt b/fints4k/src/jvmTest/kotlin/net/codinux/banking/fints/response/ResponseParserTestJvm.kt
index c1f73046..ba8a91bd 100644
--- a/fints4k/src/jvmTest/kotlin/net/codinux/banking/fints/response/ResponseParserTestJvm.kt
+++ b/fints4k/src/jvmTest/kotlin/net/codinux/banking/fints/response/ResponseParserTestJvm.kt
@@ -31,7 +31,7 @@ class ResponseParserTestJvm : FinTsTestBaseJvm() {
 
         val decodedChallengeHhdUc = TanImageDecoder().decodeChallenge(result.tanResponse?.challengeHHD_UC ?: "")
         assertThat(decodedChallengeHhdUc.decodingSuccessful).isTrue()
-        assertThat(decodedChallengeHhdUc.imageBytes.size).isEqualTo(3664)
+        assertThat(decodedChallengeHhdUc.imageBytes?.size).isEqualTo(3664)
     }
 
 }
\ No newline at end of file