DATAREDIS-999 - Use UsingWhen to apply functions to reactive Redis connections.

We now use Flux.usingWhen() to apply functions on reactive Redis connections and to release connections calling non-blocking methods.

Original Pull Request: #461

src/test/java/org/springframework/data/redis/core/ReactiveRedisTemplateUnitTests.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.redis.core;
+
+import static org.mockito.Mockito.*;
+
+import reactor.core.publisher.Mono;
+import reactor.test.StepVerifier;
+
+import org.junit.Test;
+
+import org.springframework.data.redis.connection.ReactiveRedisConnection;
+import org.springframework.data.redis.connection.ReactiveRedisConnectionFactory;
+import org.springframework.data.redis.serializer.RedisSerializationContext;
+
+/**
+ * Unit tests for {@link ReactiveRedisTemplate}.
+ *
+ * @author Mark Paluch
+ */
+public class ReactiveRedisTemplateUnitTests {
+
+	ReactiveRedisConnectionFactory connectionFactoryMock = mock(ReactiveRedisConnectionFactory.class);
+	ReactiveRedisConnection connectionMock = mock(ReactiveRedisConnection.class);
+
+	@Test // DATAREDIS-999
+	public void closeShouldUseAsyncRelease() {
+
+		when(connectionFactoryMock.getReactiveConnection()).thenReturn(connectionMock);
+		when(connectionMock.closeLater()).thenReturn(Mono.empty());
+
+		ReactiveRedisTemplate<String, String> template = new ReactiveRedisTemplate<>(connectionFactoryMock,
+				RedisSerializationContext.string());
+
+		template.execute(connection -> Mono.empty()) //
+				.as(StepVerifier::create) //
+				.verifyComplete();
+
+		verify(connectionMock).closeLater();
+		verifyNoMoreInteractions(connectionMock);
+	}
+}