DATAMONGO-1748 - Fine-tuning of nullability expressions in Kotlin extension for Criteria.

The Kotlin extensions introduced for Criteria now define relaxed null requirements for both isEqualTo(…) and the elements of the varargs handed to inValues(…).

Original pull request: #488.

spring-data-mongodb/src/main/kotlin/org/springframework/data/mongodb/core/query/CriteriaExtensions.kt

@@ -21,7 +21,7 @@ package org.springframework.data.mongodb.core.query
  * @author Sebastien Deleuze
  * @since 2.0
  */
-fun Criteria.isEqualTo(o: Any) : Criteria = `is`(o)
+fun Criteria.isEqualTo(o: Any?) : Criteria = `is`(o)
 
 /**
  * Extension for [Criteria.in] providing an `inValues` alias since `in` is a reserved keyword in Kotlin.
@@ -29,4 +29,4 @@ fun Criteria.isEqualTo(o: Any) : Criteria = `is`(o)
  * @author Sebastien Deleuze
  * @since 2.0
  */
-fun Criteria.inValues(vararg o: Any) : Criteria = `in`(*o)
+fun Criteria.inValues(vararg o: Any?) : Criteria = `in`(*o)

spring-data-mongodb/src/test/kotlin/org/springframework/data/mongodb/core/query/CriteriaExtensionsTests.kt

@@ -41,6 +41,14 @@ class CriteriaExtensionsTests {
 		Mockito.verify(criteria, Mockito.times(1)).`is`(foo)
 	}
 
+	@Test
+	fun `isEqualTo() extension should support nullable value`() {
+
+		criteria.isEqualTo(null)
+
+		Mockito.verify(criteria, Mockito.times(1)).`is`(null)
+	}
+
 	@Test
 	fun `inValues() extension should call its Java counterpart`() {
 
@@ -51,4 +59,12 @@ class CriteriaExtensionsTests {
 
 		Mockito.verify(criteria, Mockito.times(1)).`in`(foo, bar)
 	}
+
+	@Test
+	fun `inValues() extension should support nullable values`() {
+
+		criteria.inValues(null, null)
+
+		Mockito.verify(criteria, Mockito.times(1)).`in`(null, null)
+	}
 }