#40: Extract RunnerExecutor from JUnit4TestEngine

------------------------------------------------------------------------
On behalf of the community, the JUnit Lambda Team thanks
msg systems ag (http://www.msg-systems.com) for supporting
the JUnit crowdfunding campaign!
------------------------------------------------------------------------

junit4-engine/src/main/java/org/junit/gen5/engine/junit4/JUnit4TestEngine.java

@@ -10,7 +10,7 @@
 
 package org.junit.gen5.engine.junit4;
 
-import static org.junit.gen5.engine.TestExecutionResult.*;
+import static org.junit.gen5.engine.TestExecutionResult.successful;
 
 import org.junit.gen5.engine.EngineAwareTestDescriptor;
 import org.junit.gen5.engine.EngineDescriptor;
@@ -21,9 +21,7 @@
 import org.junit.gen5.engine.TestPlanSpecification;
 import org.junit.gen5.engine.junit4.descriptor.RunnerTestDescriptor;
 import org.junit.gen5.engine.junit4.discovery.JUnit4TestPlanSpecificationResolver;
-import org.junit.gen5.engine.junit4.execution.RunListenerAdapter;
-import org.junit.gen5.engine.junit4.execution.TestRun;
-import org.junit.runner.JUnitCore;
+import org.junit.gen5.engine.junit4.execution.RunnerExecutor;
 
 public class JUnit4TestEngine implements TestEngine {
 
@@ -49,28 +47,13 @@ public void execute(ExecutionRequest request) {
 	}
 
 	private void executeAllChildren(ExecutionRequest request) {
+		RunnerExecutor runnerExecutor = new RunnerExecutor(request.getEngineExecutionListener());
 		// @formatter:off
 		request.getRootTestDescriptor()
 			.getChildren()
 			.stream()
 			.map(RunnerTestDescriptor.class::cast)
-			.forEach(runnerTestDescriptor -> executeSingleRunner(runnerTestDescriptor, request.getEngineExecutionListener()));
+			.forEach(runnerExecutor::execute);
 		// @formatter:on
 	}
-
-	private void executeSingleRunner(RunnerTestDescriptor runnerTestDescriptor,
-			EngineExecutionListener engineExecutionListener) {
-		TestRun testRun = new TestRun(runnerTestDescriptor);
-		JUnitCore core = new JUnitCore();
-		core.addListener(new RunListenerAdapter(testRun, engineExecutionListener));
-		try {
-			core.run(runnerTestDescriptor.getRunner());
-		}
-		catch (Throwable t) {
-			if (testRun.isNotStarted(runnerTestDescriptor)) {
-				engineExecutionListener.executionStarted(runnerTestDescriptor);
-			}
-			engineExecutionListener.executionFinished(runnerTestDescriptor, failed(t));
-		}
-	}
 }

junit4-engine/src/main/java/org/junit/gen5/engine/junit4/execution/RunnerExecutor.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2015-2016 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v1.0 which
+ * accompanies this distribution and is available at
+ *
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+
+package org.junit.gen5.engine.junit4.execution;
+
+import static org.junit.gen5.engine.TestExecutionResult.failed;
+
+import org.junit.gen5.engine.EngineExecutionListener;
+import org.junit.gen5.engine.TestExecutionResult;
+import org.junit.gen5.engine.junit4.descriptor.RunnerTestDescriptor;
+import org.junit.runner.JUnitCore;
+
+public class RunnerExecutor {
+
+	private final EngineExecutionListener engineExecutionListener;
+
+	public RunnerExecutor(EngineExecutionListener engineExecutionListener) {
+		this.engineExecutionListener = engineExecutionListener;
+	}
+
+	public void execute(RunnerTestDescriptor runnerTestDescriptor) {
+		TestRun testRun = new TestRun(runnerTestDescriptor);
+		JUnitCore core = new JUnitCore();
+		core.addListener(new RunListenerAdapter(testRun, engineExecutionListener));
+		try {
+			core.run(runnerTestDescriptor.getRunner());
+		}
+		catch (Throwable t) {
+			reportUnexpectedFailure(testRun, runnerTestDescriptor, failed(t));
+		}
+	}
+
+	private void reportUnexpectedFailure(TestRun testRun, RunnerTestDescriptor runnerTestDescriptor,
+			TestExecutionResult result) {
+		if (testRun.isNotStarted(runnerTestDescriptor)) {
+			engineExecutionListener.executionStarted(runnerTestDescriptor);
+		}
+		engineExecutionListener.executionFinished(runnerTestDescriptor, result);
+	}
+
+}