From a50537fbaf3f6067071de5bcafa6052d1ac564fd Mon Sep 17 00:00:00 2001
From: Brian Clozel <bclozel@vmware.com>
Date: Fri, 17 Sep 2021 15:15:51 +0200
Subject: [PATCH] Polish "Fix collectionToDelimitedString failure for null
 elements."

Fixes gh-27419
---
 .../java/org/springframework/util/StringUtilsTests.java     | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/spring-core/src/test/java/org/springframework/util/StringUtilsTests.java b/spring-core/src/test/java/org/springframework/util/StringUtilsTests.java
index 2aae6260dd0..2b46f73a56a 100644
--- a/spring-core/src/test/java/org/springframework/util/StringUtilsTests.java
+++ b/spring-core/src/test/java/org/springframework/util/StringUtilsTests.java
@@ -17,6 +17,7 @@
 package org.springframework.util;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Locale;
 import java.util.Properties;
 
@@ -777,4 +778,9 @@ class StringUtilsTests {
 		assertThat(StringUtils.split(null, null)).isNull();
 	}
 
+	@Test
+	void collectionToDelimitedStringWithNullValuesShouldNotFail() {
+		assertThat(StringUtils.collectionToCommaDelimitedString(Collections.singletonList(null))).isEqualTo("null");
+	}
+
 }