Added tests for HystrixConcurrencyStrategy

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/hystrix/SleuthHystrixConcurrencyStrategy.java

@@ -79,13 +79,13 @@ public class SleuthHystrixConcurrencyStrategy extends HystrixConcurrencyStrategy
 	private void logCurrentStateOfHysrixPlugins(HystrixEventNotifier eventNotifier,
 			HystrixMetricsPublisher metricsPublisher,
 			HystrixPropertiesStrategy propertiesStrategy) {
-		log.info("Current Hystrix plugins configuration is ["
+		log.debug("Current Hystrix plugins configuration is ["
 				+ "concurrencyStrategy [" + this.delegate + "],"
 				+ "eventNotifier [" + eventNotifier + "],"
 				+ "metricPublisher [" + metricsPublisher + "],"
 				+ "propertiesStrategy [" + propertiesStrategy + "],"
 				+ "]");
-		log.info("Resetting Hystrix custom strategies and registering Sleuth Hystrix Concurrency Strategy.");
+		log.debug("Registering Sleuth Hystrix Concurrency Strategy.");
 	}
 
 	@Override
@@ -95,7 +95,8 @@ public class SleuthHystrixConcurrencyStrategy extends HystrixConcurrencyStrategy
 		return new HystrixTraceCallable<>(this.tracer, this.traceKeys, wrappedCallable);
 	}
 
-	private static class HystrixTraceCallable<S> implements Callable<S> {
+	// Visible for testing
+	static class HystrixTraceCallable<S> implements Callable<S> {
 
 		private Tracer tracer;
 		private TraceKeys traceKeys;

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/hystrix/SleuthHystrixConcurrencyStrategyTest.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2013-2016 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.instrument.hystrix;
+
+import java.util.concurrent.Callable;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+import org.springframework.cloud.sleuth.TraceKeys;
+import org.springframework.cloud.sleuth.Tracer;
+
+import com.netflix.hystrix.strategy.HystrixPlugins;
+import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategy;
+import com.netflix.hystrix.strategy.eventnotifier.HystrixEventNotifier;
+import com.netflix.hystrix.strategy.executionhook.HystrixCommandExecutionHook;
+import com.netflix.hystrix.strategy.metrics.HystrixMetricsPublisher;
+import com.netflix.hystrix.strategy.properties.HystrixPropertiesStrategy;
+
+import static org.assertj.core.api.BDDAssertions.then;
+
+/**
+ * @author Marcin Grzejszczak
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class SleuthHystrixConcurrencyStrategyTest {
+
+	@Mock Tracer tracer;
+	TraceKeys traceKeys = new TraceKeys();
+
+	@Before
+	@After
+	public void setup() {
+		HystrixPlugins.reset();
+	}
+
+	@Test
+	public void should_not_override_existing_custom_strategies() {
+		HystrixPlugins.getInstance().registerCommandExecutionHook(new MyHystrixCommandExecutionHook());
+		HystrixPlugins.getInstance().registerEventNotifier(new MyHystrixEventNotifier());
+		HystrixPlugins.getInstance().registerMetricsPublisher(new MyHystrixMetricsPublisher());
+		HystrixPlugins.getInstance().registerPropertiesStrategy(new MyHystrixPropertiesStrategy());
+
+		new SleuthHystrixConcurrencyStrategy(this.tracer, this.traceKeys);
+
+		then(HystrixPlugins
+				.getInstance().getCommandExecutionHook()).isExactlyInstanceOf(MyHystrixCommandExecutionHook.class);
+		then(HystrixPlugins.getInstance()
+				.getEventNotifier()).isExactlyInstanceOf(MyHystrixEventNotifier.class);
+		then(HystrixPlugins.getInstance()
+				.getMetricsPublisher()).isExactlyInstanceOf(MyHystrixMetricsPublisher.class);
+		then(HystrixPlugins.getInstance()
+				.getPropertiesStrategy()).isExactlyInstanceOf(MyHystrixPropertiesStrategy.class);
+	}
+
+	@Test
+	public void should_wrap_delegates_callable_in_trace_callable_when_delegate_is_present()
+			throws Exception {
+		HystrixPlugins.getInstance().registerConcurrencyStrategy(new MyHystrixConcurrencyStrategy());
+		SleuthHystrixConcurrencyStrategy strategy = new SleuthHystrixConcurrencyStrategy(
+				this.tracer, this.traceKeys);
+
+		Callable<String> callable = strategy.wrapCallable(() -> "hello");
+
+		then(callable).isInstanceOf(SleuthHystrixConcurrencyStrategy.HystrixTraceCallable.class);
+		then(callable.call()).isEqualTo("executed_custom_callable");
+	}
+
+	@Test
+	public void should_wrap_callable_in_trace_callable_when_delegate_is_present()
+			throws Exception {
+		SleuthHystrixConcurrencyStrategy strategy = new SleuthHystrixConcurrencyStrategy(
+				this.tracer, this.traceKeys);
+
+		Callable<String> callable = strategy.wrapCallable(() -> "hello");
+
+		then(callable).isInstanceOf(SleuthHystrixConcurrencyStrategy.HystrixTraceCallable.class);
+	}
+
+	static class MyHystrixCommandExecutionHook extends HystrixCommandExecutionHook {}
+	@SuppressWarnings("unchecked")
+	static class MyHystrixConcurrencyStrategy extends HystrixConcurrencyStrategy {
+		@Override public <T> Callable<T> wrapCallable(Callable<T> callable) {
+			return () -> (T) "executed_custom_callable";
+		}
+	}
+	static class MyHystrixEventNotifier extends HystrixEventNotifier {}
+	static class MyHystrixMetricsPublisher extends HystrixMetricsPublisher {}
+	static class MyHystrixPropertiesStrategy extends HystrixPropertiesStrategy {}
+}