DATAMONGO-773 - Verify that @DBRef fields can be included in query.

Added test cases to verify that projection search with included @DBRef fields works as expected.

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

@@ -2464,6 +2464,33 @@ public class MongoTemplateTests {
 		assertThat(result.models.get(0).value(), is("mongodb"));
 	}
 
+	/**
+	 * @see DATAMONGO-773
+	 */
+	@Test
+	public void testShouldSupportQueryWithIncludedDbRefField() {
+
+		Sample sample = new Sample("47111", "foo");
+		template.save(sample);
+
+		DocumentWithDBRefCollection doc = new DocumentWithDBRefCollection();
+		doc.id = "4711";
+		doc.dbRefProperty = sample;
+
+		template.save(doc);
+
+		Query qry = query(where("id").is(doc.id));
+		qry.fields().include("dbRefProperty");
+
+		List<DocumentWithDBRefCollection> result = template.find(qry, DocumentWithDBRefCollection.class);
+
+		assertThat(result, is(notNullValue()));
+		assertThat(result, hasSize(1));
+		assertThat(result.get(0), is(notNullValue()));
+		assertThat(result.get(0).dbRefProperty, is(notNullValue()));
+		assertThat(result.get(0).dbRefProperty.field, is(sample.field));
+	}
+
 	static class DocumentWithDBRefCollection {
 
 		@Id public String id;

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/QueryMapperUnitTests.java

@@ -553,6 +553,21 @@ public class QueryMapperUnitTests {
 		assertThat(inObject.get(0), is(instanceOf(com.mongodb.DBRef.class)));
 	}
 
+	/**
+	 * @see DATAMONGO-773
+	 */
+	@Test
+	public void queryMapperShouldBeAbleToProcessQueriesThatIncludeDbRefFields() {
+
+		BasicMongoPersistentEntity<?> persistentEntity = context.getPersistentEntity(WithDBRef.class);
+
+		Query qry = query(where("someString").is("abc"));
+		qry.fields().include("reference");
+
+		DBObject mappedFields = mapper.getMappedObject(qry.getFieldsObject(), persistentEntity);
+		assertThat(mappedFields, is(notNullValue()));
+	}
+
 	class IdWrapper {
 		Object id;
 	}