fix delete for void return type (spring-attic#2177)

Author: dmitry-s

spring-cloud-gcp-data-datastore/src/main/java/org/springframework/cloud/gcp/data/datastore/repository/query/PartTreeDatastoreQuery.java

@@ -206,7 +206,7 @@ else if (!returnedTypeIsNumber) {
 		StructuredQuery.Builder<?> structredQueryBuilder = queryBuilderSupplier.get();
 		structredQueryBuilder.setKind(this.datastorePersistentEntity.kindName());
 
-		boolean singularResult = !isCountingQuery && collectionType == null;
+		boolean singularResult = (!isCountingQuery && collectionType == null) && !this.tree.isDelete();
 		DatastoreResultsIterable rawResults = getDatastoreTemplate()
 				.queryKeysOrEntities(
 						applyQueryBody(parameters, structredQueryBuilder, total, singularResult, null),

spring-cloud-gcp-data-datastore/src/test/java/org/springframework/cloud/gcp/data/datastore/it/DatastoreIntegrationTests.java

@@ -358,6 +358,12 @@ public void testSaveAndDeleteRepository() throws InterruptedException {
 				.map(TestEntity::getId).collect(Collectors.toList())).contains(4L);
 
 		assertThat(this.testEntityRepository.deleteBySize(1L)).isEqualTo(3);
+		assertThat(this.testEntityRepository.countBySize(1L)).isEqualTo(0);
+
+		this.testEntityRepository.saveAll(this.allTestEntities);
+
+		this.testEntityRepository.deleteBySizeEquals(1L);
+		assertThat(this.testEntityRepository.countBySize(1L)).isEqualTo(0);
 
 		//test saveAll for iterable
 		Iterable<TestEntity> testEntities = () -> this.allTestEntities.iterator();

spring-cloud-gcp-data-datastore/src/test/java/org/springframework/cloud/gcp/data/datastore/it/TestEntityRepository.java

@@ -66,6 +66,8 @@ public interface TestEntityRepository extends DatastoreRepository<TestEntity, Lo
 
 	int deleteBySize(long size);
 
+	void deleteBySizeEquals(long size);
+
 	List<TestEntity> removeByColor(String color);
 
 	List<TestEntity> findByShape(Shape shape);

spring-cloud-gcp-data-datastore/src/test/java/org/springframework/cloud/gcp/data/datastore/repository/query/PartTreeDatastoreQueryTests.java

@@ -118,7 +118,7 @@ public void initMocks() {
 		this.datastoreMappingContext = new DatastoreMappingContext();
 		this.datastoreEntityConverter = mock(DatastoreEntityConverter.class);
 		this.readWriteConversions = new TwoStepsConversions(new DatastoreCustomConversions(), null,
-				datastoreMappingContext);
+				this.datastoreMappingContext);
 		when(this.datastoreTemplate.getDatastoreEntityConverter())
 				.thenReturn(this.datastoreEntityConverter);
 		when(this.datastoreEntityConverter.getConversions())
@@ -564,6 +564,73 @@ private void prepareSliceResults(int offset, Integer queryLimit, Boolean hasNext
 		);
 	}
 
+	@Test
+	public void deleteTest() throws NoSuchMethodException {
+		queryWithMockResult("deleteByAction", null,
+				getClass().getMethod("countByAction", String.class));
+
+		this.partTreeDatastoreQuery = createQuery(false, false);
+
+		Object[] params = new Object[] { "BUY" };
+
+		prepareDeleteResults(false);
+
+		when(this.queryMethod.getReturnedObjectType()).thenReturn((Class) int.class);
+
+		this.partTreeDatastoreQuery.execute(params);
+
+		verify(this.datastoreTemplate, times(0))
+				.query(any(), (Function) any());
+
+		verify(this.datastoreTemplate, times(1))
+				.queryKeysOrEntities(any(), any());
+
+		verify(this.datastoreTemplate, times(1))
+				.deleteAllById(eq(Arrays.asList(3, 4, 5)), any());
+	}
+
+	@Test
+	public void deleteReturnCollectionTest() throws NoSuchMethodException {
+		queryWithMockResult("deleteByAction", null,
+				getClass().getMethod("countByAction", String.class));
+
+		this.partTreeDatastoreQuery = createQuery(false, false);
+
+		Object[] params = new Object[] { "BUY" };
+
+		prepareDeleteResults(true);
+
+		when(this.queryMethod.getCollectionReturnType()).thenReturn(List.class);
+
+		List result = (List) this.partTreeDatastoreQuery.execute(params);
+		assertThat(result).containsExactly(3, 4, 5);
+
+		verify(this.datastoreTemplate, times(0))
+				.query(any(), (Function) any());
+
+		verify(this.datastoreTemplate, times(1))
+				.queryKeysOrEntities(any(), any());
+
+		verify(this.datastoreTemplate, times(1))
+				.deleteAll(eq(Arrays.asList(3, 4, 5)));
+	}
+	private void prepareDeleteResults(boolean isCollection) {
+		Cursor cursor = Cursor.copyFrom("abc".getBytes());
+		List<Integer> datastoreMatchingRecords = Arrays.asList(3, 4, 5);
+		when(this.datastoreTemplate.queryKeysOrEntities(any(), any())).thenAnswer((invocation) -> {
+			StructuredQuery<?> statement = invocation.getArgument(0);
+			StructuredQuery.Builder builder = isCollection ? StructuredQuery.newEntityQueryBuilder()
+					: StructuredQuery.newKeyQueryBuilder();
+			StructuredQuery<?> expected = builder
+					.setFilter(PropertyFilter.eq("action", "BUY"))
+					.setKind("trades")
+					.build();
+
+			assertThat(statement).isEqualTo(expected);
+			return new DatastoreResultsIterable(datastoreMatchingRecords.iterator(), cursor);
+		});
+	}
+
 	@Test
 	public void unspecifiedParametersTest() throws NoSuchMethodException {
 		this.expectedException.expectMessage(