Added a test for tracing the tracer

spring-cloud-sleuth-stream/pom.xml

@@ -59,6 +59,11 @@
 			<artifactId>spring-boot-starter-test</artifactId>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.aspectj</groupId>
+			<artifactId>aspectjweaver</artifactId>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 
 </project>

spring-cloud-sleuth-stream/src/test/java/org/springframework/cloud/sleuth/stream/StreamSpanListenerTests.java

@@ -84,8 +84,10 @@ public class StreamSpanListenerTests {
 	@Test
 	public void acquireAndRelease() {
 		Span context = this.tracer.createSpan("http:foo");
+
 		this.tracer.close(context);
-		assertEquals(1, this.test.spans.size());
+
+		assertThat(this.test.spans).hasSize(1);
 	}
 
 	@Test
@@ -96,8 +98,10 @@ public class StreamSpanListenerTests {
 		context.logEvent(Span.CLIENT_SEND);
 		logServerReceived(parent);
 		logServerSent(this.spanReporter, parent);
+
 		this.tracer.close(context);
-		assertEquals(2, this.test.spans.size());
+
+		assertThat(this.test.spans).hasSize(2);
 	}
 
 	void logServerReceived(Span parent) {

spring-cloud-sleuth-stream/src/test/java/org/springframework/cloud/sleuth/stream/TraceIgnoringChannelInterceptorTests.java

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2013-2015 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.cloud.sleuth.stream;
+
+import javax.annotation.PostConstruct;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.cloud.sleuth.Sampler;
+import org.springframework.cloud.sleuth.Span;
+import org.springframework.cloud.sleuth.Tracer;
+import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
+import org.springframework.cloud.sleuth.util.ExceptionUtils;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.integration.core.MessagingTemplate;
+import org.springframework.integration.support.MessageBuilder;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import static org.assertj.core.api.BDDAssertions.then;
+
+/**
+ * @author Dave Syer
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = TraceIgnoringChannelInterceptorTests.App.class)
+@DirtiesContext
+public class TraceIgnoringChannelInterceptorTests {
+
+	@Autowired Tracer tracer;
+	@Autowired App app;
+	@Autowired MessagingTemplate messagingTemplate;
+
+	@Before
+	public void init() {
+		this.app.clear();
+	}
+
+	@After
+	public void close() {
+		then(ExceptionUtils.getLastException()).isNull();
+		this.app.clear();
+	}
+
+	@Test
+	public void shouldNotTraceTheTracer() {
+		this.messagingTemplate.send(MessageBuilder.withPayload("hi").build());
+
+		Spans spans = this.app.listener.poll();
+
+		then(spans).isNull();
+		then(this.tracer.getCurrentSpan()).isNull();
+	}
+
+	@Configuration
+	@EnableAutoConfiguration
+	static class App {
+
+		private final BlockingQueue<Span> spans = new LinkedBlockingQueue<>();
+
+		@Autowired StreamSpanReporter listener;
+
+		@Bean MessagingTemplate messagingTemplate(SleuthSource sleuthSource) {
+			return new MessagingTemplate(sleuthSource.output());
+		}
+
+		@Bean Sampler alwaysSampler() {
+			return new AlwaysSampler();
+		}
+
+
+		@PostConstruct
+		public void init() {
+			this.listener.setQueue(this.spans);
+		}
+
+		public void clear() {
+			this.spans.clear();
+		}
+	}
+}