Add Test for LeakAwareDataBufferFactory

spring-core/src/test/java/org/springframework/core/io/buffer/LeakAwareDataBuffer.java

@@ -44,11 +44,14 @@ class LeakAwareDataBuffer implements PooledDataBuffer {
 		Assert.notNull(dataBufferFactory, "DataBufferFactory must not be null");
 		this.delegate = delegate;
 		this.dataBufferFactory = dataBufferFactory;
-		this.leakError = createLeakError();
+		this.leakError = createLeakError(delegate);
 	}
 
-	private static AssertionError createLeakError() {
-		AssertionError result = new AssertionError("Leak detected in test case");
+	private static AssertionError createLeakError(DataBuffer delegate) {
+		String message = String.format("DataBuffer leak detected: {%s} has not been released.%n" +
+				"Stack trace of buffer allocation statement follows:",
+				delegate);
+		AssertionError result = new AssertionError(message);
 		// remove first four irrelevant stack trace elements
 		StackTraceElement[] oldTrace = result.getStackTrace();
 		StackTraceElement[] newTrace = new StackTraceElement[oldTrace.length - 4];

spring-core/src/test/java/org/springframework/core/io/buffer/LeakAwareDataBufferFactory.java

@@ -20,6 +20,7 @@ import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.jetbrains.annotations.NotNull;
 import org.junit.After;
 
 import org.springframework.util.Assert;
@@ -74,17 +75,18 @@ public class LeakAwareDataBufferFactory implements DataBufferFactory {
 	}
 
 	@Override
-	public LeakAwareDataBuffer allocateBuffer() {
-		LeakAwareDataBuffer dataBuffer =
-				new LeakAwareDataBuffer(this.delegate.allocateBuffer(), this);
-		this.created.add(dataBuffer);
-		return dataBuffer;
+	public DataBuffer allocateBuffer() {
+		return allocateBufferInternal(this.delegate.allocateBuffer());
 	}
 
 	@Override
-	public LeakAwareDataBuffer allocateBuffer(int initialCapacity) {
-		LeakAwareDataBuffer dataBuffer =
-				new LeakAwareDataBuffer(this.delegate.allocateBuffer(initialCapacity), this);
+	public DataBuffer allocateBuffer(int initialCapacity) {
+		return allocateBufferInternal(this.delegate.allocateBuffer(initialCapacity));
+	}
+
+	@NotNull
+	private DataBuffer allocateBufferInternal(DataBuffer delegateBuffer) {
+		LeakAwareDataBuffer dataBuffer = new LeakAwareDataBuffer(delegateBuffer, this);
 		this.created.add(dataBuffer);
 		return dataBuffer;
 	}

spring-core/src/test/java/org/springframework/core/io/buffer/LeakAwareDataBufferFactoryTests.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2002-2018 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
+ *
+ *      http://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.core.io.buffer;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+import static org.springframework.core.io.buffer.DataBufferUtils.release;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class LeakAwareDataBufferFactoryTests {
+
+	private final LeakAwareDataBufferFactory bufferFactory = new LeakAwareDataBufferFactory();
+
+
+	@Test
+	public void leak() {
+		DataBuffer dataBuffer = this.bufferFactory.allocateBuffer();
+		try {
+			this.bufferFactory.checkForLeaks();
+			fail("AssertionError expected");
+		}
+		catch (AssertionError expected) {
+			// ignore
+		}
+		finally {
+			release(dataBuffer);
+		}
+	}
+
+	@Test
+	public void noLeak() {
+		DataBuffer dataBuffer = this.bufferFactory.allocateBuffer();
+		release(dataBuffer);
+		this.bufferFactory.checkForLeaks();
+	}
+
+}