From 077bfaf095a3ed8ed1e0d9da3888e79aa75dab78 Mon Sep 17 00:00:00 2001
From: Sam Brannen <104798+sbrannen@users.noreply.github.com>
Date: Wed, 17 Jun 2026 14:14:41 +0200
Subject: [PATCH] Polish contribution

See gh-36830
---
 .../DefaultConversionServiceTests.java        | 41 ++++++++++---------
 1 file changed, 22 insertions(+), 19 deletions(-)

diff --git a/spring-core/src/test/java/org/springframework/core/convert/converter/DefaultConversionServiceTests.java b/spring-core/src/test/java/org/springframework/core/convert/converter/DefaultConversionServiceTests.java
index 70aeea74100..51202425e41 100644
--- a/spring-core/src/test/java/org/springframework/core/convert/converter/DefaultConversionServiceTests.java
+++ b/spring-core/src/test/java/org/springframework/core/convert/converter/DefaultConversionServiceTests.java
@@ -232,37 +232,40 @@ class DefaultConversionServiceTests {
 		assertThat(conversionService.convert("", Number.class)).isNull();
 	}
 
-	@Test
-	void stringToDataSize() {
-		assertThat(conversionService.convert("10B", DataSize.class)).isEqualTo(DataSize.ofBytes(10));
-		assertThat(conversionService.convert("+10KB", DataSize.class)).isEqualTo(DataSize.ofKilobytes(10));
-		assertThat(conversionService.convert("-10MB", DataSize.class)).isEqualTo(DataSize.ofMegabytes(-10));
-		assertThat(conversionService.convert("10", DataSize.class)).isEqualTo(DataSize.ofBytes(10));
+	@Test  // gh-36830
+	void stringToDataSizeWithInvalidString() {
+		assertThatExceptionOfType(ConversionFailedException.class)
+				.isThrownBy(() -> conversionService.convert("10WB", DataSize.class))
+				.havingRootCause()
+					.isInstanceOf(IllegalArgumentException.class)
+					.withMessage("Unknown data unit suffix 'WB'");
 	}
 
-	@Test
-	void stringToDataSizeEmptyString() {
+	@Test  // gh-36830
+	void stringToDataSizeWithEmptyString() {
 		assertThat(conversionService.convert("", DataSize.class)).isNull();
 	}
 
-	@Test
-	void stringToDataSizeInvalidString() {
-		assertThatExceptionOfType(ConversionFailedException.class).isThrownBy(() ->
-				conversionService.convert("10WB", DataSize.class));
+	@Test  // gh-36830
+	void stringToDataSize() {
+		assertThat(conversionService.convert("10", DataSize.class)).isEqualTo(DataSize.ofBytes(10));
+		assertThat(conversionService.convert("10B", DataSize.class)).isEqualTo(DataSize.ofBytes(10));
+		assertThat(conversionService.convert("+10KB", DataSize.class)).isEqualTo(DataSize.ofKilobytes(10));
+		assertThat(conversionService.convert("-10MB", DataSize.class)).isEqualTo(DataSize.ofMegabytes(-10));
 	}
 
-	@Test
+	@Test  // gh-36830
+	void numberToDataSizeWithDecimalNumber() {
+		assertThatExceptionOfType(ConversionFailedException.class)
+				.isThrownBy(() -> conversionService.convert(10.5, DataSize.class));
+	}
+
+	@Test  // gh-36830
 	void numberToDataSize() {
 		assertThat(conversionService.convert(10, DataSize.class)).isEqualTo(DataSize.ofBytes(10));
 		assertThat(conversionService.convert(-10L, DataSize.class)).isEqualTo(DataSize.ofBytes(-10));
 	}
 
-	@Test
-	void numberToDataSizeWithDecimalNumber() {
-		assertThatExceptionOfType(ConversionFailedException.class).isThrownBy(() ->
-				conversionService.convert(10.5, DataSize.class));
-	}
-
 	@Test
 	void stringToEnum() {
 		assertThat(conversionService.convert("BAR", Foo.class)).isEqualTo(Foo.BAR);