ant and junit 5 – outputting test duration and failure to the log

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ant and junit 5 – outputting test duration and failure to the log

July 28th, 2018 by Jeanne Boyarsky

In JUnit 5, you use the junitlauncher Ant task rather than the junit Ant task. Unfortunately, this isn’t a drop in replacement. In addition to needing a workaround to set system properties, you also need a workaround to write the test results to the console log.

JUnit 4

With JUnit 4 and Ant, you got output that looked list this for each test run. In the console. Real time while the build was running. This was really useful.

[junit] Running com.javaranch.jforum.MissingHeadTagTest
[junit] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 1.685 sec

The problem

JUnit 5 itself provides a number of built in options for this. However, Ant integration renders this “not very useful” for a few reasons.

    1. I want to use the legacy listeners. For example:
      <listener type="legacy-xml" sendSysOut="true" sendSysErr="true" />
      <listener type="legacy-plain"sendSysOut="true"sendSysErr="true"/>

      However, if I enabled sendSysOut and sendSysErr to them, all the listeners present redirect away from System.out. This means if I try to use the built it LoggingListener, it also redirects to the file and I don’t see it in the console. This means, I have to chose between the legacy listeners and seeing real time data.

    2. Ant seems to pass a fileset as individual tests. This means that running this code, prints a summary for each test rather than the whole thing at the end.
      <junitlauncher haltOnFailure="true" printsummary="true">
           <classpath refid="test.classpath" />
           <testclasses outputdir="build/test-report">
      	<fileset dir="build/test">
      	  <include name="**/*Tests.class" />

      It looks like this. The summary tells me about each run, but not with the test names so not useful anyway.

      [junitlauncher] Test run finished after 117 ms
      [junitlauncher] [         3 containers found      ]
      [junitlauncher] [         0 containers skipped    ]
      [junitlauncher] [         3 containers started    ]
      [junitlauncher] [         0 containers aborted    ]
      [junitlauncher] [         3 containers successful ]
      [junitlauncher] [         0 containers failed     ]
      [junitlauncher] [        15 tests found           ]
      [junitlauncher] [         0 tests skipped         ]
      [junitlauncher] [        15 tests started         ]
      [junitlauncher] [         0 tests aborted         ]
      [junitlauncher] [        15 tests successful      ]
      [junitlauncher] [         0 tests failed          ]
      [junitlauncher] Test run finished after 14 ms
      [junitlauncher] [         2 containers found      ]
      [junitlauncher] [         0 containers skipped    ]
      [junitlauncher] [         2 containers started    ]
      [junitlauncher] [         0 containers aborted    ]
      [junitlauncher] [         2 containers successful ]
      [junitlauncher] [         0 containers failed     ]
      [junitlauncher] [        10 tests found           ]
      [junitlauncher] [         0 tests skipped         ]
      [junitlauncher] [        10 tests started         ]
      [junitlauncher] [         0 tests aborted         ]
      [junitlauncher] [        10 tests successful      ]
      [junitlauncher] [         0 tests failed          ]
    3. If I use JUnit Launcher’s fail on error property, it fails on the first test rather than telling me about all of them. (I don’t use this feature anyway.)
    4. Custom extensions also have their system out/err redirected to the legacy listeners.

The solution

This feels like a hacky workaround. But I only have one project that uses Ant so I don’t have to worry about duplicate code. The legacy listeners are useful so I don’t want to get rid of them.

I wrote a custom listener that stores the results in memory for each test and writes it to disk after each test class runs. That way it gets all the data, not just the last one. And then Ant writes it out.

<target name="test.junit.launcher" depends="compile">
		<junitlauncher haltOnFailure="false" printsummary="false">
			<classpath refid="test.classpath" />
			<testclasses outputdir="build/test-report">
				<fileset dir="build/test">
					<include name="**/*Tests.class" />
				<listener type="legacy-xml" sendSysOut="true" sendSysErr="true" />
				<listener type="legacy-plain" sendSysOut="true" sendSysErr="true" />
				<listener classname="com.example.project.CodeRanchListener" />
		<loadfile property="summary" srcFile="build/status-as-tests-run.txt" />

And the listener

package com.example.project;

import java.time.*;

import org.junit.platform.engine.*;
import org.junit.platform.engine.TestDescriptor.*;
import org.junit.platform.engine.TestExecutionResult.*;
import org.junit.platform.launcher.*;

public class MyListener implements TestExecutionListener {
	private StringWriter inMemoryWriter = new StringWriter();

	private int numSkippedInCurrentClass;
	private int numAbortedInCurrentClass;
	private int numSucceededInCurrentClass;
	private int numFailedInCurrentClass;
	private Instant startCurrentClass;

	private void resetCountsForNewClass() {
		numSkippedInCurrentClass = 0;
		numAbortedInCurrentClass = 0;
		numSucceededInCurrentClass = 0;
		numFailedInCurrentClass = 0;
		startCurrentClass =;

	public void executionStarted(TestIdentifier testIdentifier) {
		if ("[engine:junit-jupiter]".equals(testIdentifier.getParentId().orElse(""))) {
			println("Ran " + testIdentifier.getLegacyReportingName());

	public void executionSkipped(TestIdentifier testIdentifier, String reason) {

	public void executionFinished(TestIdentifier testIdentifier, TestExecutionResult testExecutionResult) {
		if ("[engine:junit-jupiter]".equals(testIdentifier.getParentId().orElse(""))) {
			int totalTestsInClass = numSucceededInCurrentClass + numAbortedInCurrentClass
					+ numFailedInCurrentClass + numSkippedInCurrentClass;
			Duration duration = Duration.between(startCurrentClass,;
			double numSeconds = duration.getNano() / (double) 1_000_000_000;
			String output = String.format("Tests run: %d, Failures: %d, Aborted: %d, Skipped: %d, Time elapsed: %f sec",
					totalTestsInClass, numFailedInCurrentClass, numAbortedInCurrentClass,
					numSkippedInCurrentClass, numSeconds);

		// don't count containers since looking for legacy JUnit 4 counting style
		if (testIdentifier.getType() == Type.TEST) {
			if (testExecutionResult.getStatus() == Status.SUCCESSFUL) {
			} else if (testExecutionResult.getStatus() == Status.ABORTED) {
				println("  ABORTED: " + testIdentifier.getDisplayName());
			} else if (testExecutionResult.getStatus() == Status.FAILED) {
				println("  FAILED: " + testIdentifier.getDisplayName());
	private void println(String str) {
		inMemoryWriter.write(str + "\n");
	 * Append to file on disk since listener can't write to System.out (becuase legacy listeners enabled)
	private void flushToDisk() {
		try (FileWriter writer = new FileWriter("build/status-as-tests-run.txt", true)) {
		} catch (IOException e) {
			throw new UncheckedIOException(e);

	public void testPlanExecutionFinished(TestPlan testPlan) {


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