Polish contribution

See gh-31808

Author: sbrannen

spring-core/src/test/java/org/springframework/util/comparator/ComparatorsTest.java renamed to spring-core/src/test/java/org/springframework/util/comparator/ComparatorsTests.java

@@ -21,31 +21,44 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
- * Tests for {@link Comparators}
+ * Tests for {@link Comparators}.
+ *
+ * @since 6.1.2
+ * @author Mathieu Amblard
+ * @author Sam Brannen
  */
-class ComparatorsTest {
+class ComparatorsTests {
 
 	@Test
-	void shouldCompareWithNullsLow() {
-		assertThat(Comparators.nullsLow().compare(null, "boo")).isNegative();
+	void nullsLow() {
+		assertThat(Comparators.nullsLow().compare("boo", "boo")).isZero();
 		assertThat(Comparators.nullsLow().compare(null, null)).isZero();
+		assertThat(Comparators.nullsLow().compare(null, "boo")).isNegative();
+		assertThat(Comparators.nullsLow().compare("boo", null)).isPositive();
 	}
 
 	@Test
-	void shouldCompareWithNullsLowAndComparator() {
-		assertThat(Comparators.nullsLow(String::compareTo).compare(null, "boo")).isNegative();
+	void nullsLowWithExplicitComparator() {
+		assertThat(Comparators.nullsLow(String::compareTo).compare("boo", "boo")).isZero();
 		assertThat(Comparators.nullsLow(String::compareTo).compare(null, null)).isZero();
+		assertThat(Comparators.nullsLow(String::compareTo).compare(null, "boo")).isNegative();
+		assertThat(Comparators.nullsLow(String::compareTo).compare("boo", null)).isPositive();
 	}
 
 	@Test
-	void shouldCompareWithNullsHigh() {
-		assertThat(Comparators.nullsHigh().compare(null, "boo")).isPositive();
+	void nullsHigh() {
+		assertThat(Comparators.nullsHigh().compare("boo", "boo")).isZero();
 		assertThat(Comparators.nullsHigh().compare(null, null)).isZero();
+		assertThat(Comparators.nullsHigh().compare(null, "boo")).isPositive();
+		assertThat(Comparators.nullsHigh().compare("boo", null)).isNegative();
 	}
 
 	@Test
-	void shouldCompareWithNullsHighAndComparator() {
-		assertThat(Comparators.nullsHigh(String::compareTo).compare(null, "boo")).isPositive();
+	void nullsHighWithExplicitComparator() {
+		assertThat(Comparators.nullsHigh(String::compareTo).compare("boo", "boo")).isZero();
 		assertThat(Comparators.nullsHigh(String::compareTo).compare(null, null)).isZero();
+		assertThat(Comparators.nullsHigh(String::compareTo).compare(null, "boo")).isPositive();
+		assertThat(Comparators.nullsHigh(String::compareTo).compare("boo", null)).isNegative();
 	}
-}
+
+}

spring-core/src/test/java/org/springframework/util/comparator/NullSafeComparatorTests.java

@@ -36,16 +36,23 @@ class NullSafeComparatorTests {
 	void shouldCompareWithNullsLow() {
 		@SuppressWarnings("deprecation")
 		Comparator<String> c = NullSafeComparator.NULLS_LOW;
-		assertThat(c.compare(null, "boo")).isLessThan(0);
+
+		assertThat(c.compare("boo", "boo")).isZero();
+		assertThat(c.compare(null, null)).isZero();
+		assertThat(c.compare(null, "boo")).isNegative();
+		assertThat(c.compare("boo", null)).isPositive();
 	}
 
 	@Test
 	@SuppressWarnings("unchecked")
 	void shouldCompareWithNullsHigh() {
 		@SuppressWarnings("deprecation")
 		Comparator<String> c = NullSafeComparator.NULLS_HIGH;
-		assertThat(c.compare(null, "boo")).isGreaterThan(0);
-		assertThat(c.compare(null, null)).isEqualTo(0);
+
+		assertThat(c.compare("boo", "boo")).isZero();
+		assertThat(c.compare(null, null)).isZero();
+		assertThat(c.compare(null, "boo")).isPositive();
+		assertThat(c.compare("boo", null)).isNegative();
 	}
 
 }