Apply sort of unpaged Pageable to query.

Original pull request: spring-projects#4773
Closes spring-projects#4771

Author: christophstrobl

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Query.java

@@ -286,6 +286,9 @@ public Query withHint(Document hint) {
 	public Query with(Pageable pageable) {
 
 		if (pageable.isUnpaged()) {
+			if(pageable.getSort().isSorted()) {
+				return with(pageable.getSort());
+			}
 			return this;
 		}
 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/query/QueryTests.java

@@ -23,6 +23,7 @@
 import org.junit.jupiter.api.Test;
 import org.springframework.aop.framework.ProxyFactory;
 import org.springframework.data.domain.Limit;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.domain.Sort.Direction;
 import org.springframework.data.domain.Sort.Order;
@@ -366,6 +367,15 @@ void queryOfShouldWorkOnProxiedObjects() {
 		compareQueries(target, source);
 	}
 
+	@Test // GH-4771
+	void appliesSortOfUnpagedPageable() {
+
+		Query query = new Query();
+		query.with(Pageable.unpaged(Sort.by("sortMe")));
+
+		assertThat(query.isSorted()).isTrue();
+	}
+
 	private void compareQueries(Query actual, Query expected) {
 
 		assertThat(actual.getCollation()).isEqualTo(expected.getCollation());