junit-team/junit5 · error · JUnitException

Failed to create XML events file

Error message

Failed to create XML events file

What it means

Thrown as a JUnitException by OpenTestReportGeneratingListener.createDocumentWriter() (orElseGet branch) when Events.createDocumentWriter() fails to create or write the open-test-report.xml file under the root output directory. This is the DEFAULT transport — it fires only when junit.platform.reporting.open.xml.socket is NOT set. The output directory comes from TestPlan.getOutputDirectoryCreator().getRootDirectory(), which honors junit.platform.reporting.output.dir. Normally surfaces wrapped as error 145.

Solutions

1. Set junit.platform.reporting.output.dir to a writable absolute path, e.g. -Djunit.platform.reporting.output.dir=/tmp/junit-reports.
2. Confirm Files.isWritable(root) on the directory returned by the OutputDirectoryCreator before the run.
3. Free disk space on the volume hosting the output directory.
4. Disable any process that locks files in the output directory (search indexers, AV) or move the output off a network mount.

Example fix

// before
-Djunit.platform.reporting.output.dir=/readonly/build/reports

// after
-Djunit.platform.reporting.output.dir=/var/tmp/junit-reports

// Preflight: confirm the creator's root directory is writable before launch.
Path root = testPlan.getOutputDirectoryCreator().getRootDirectory();
if (!Files.isDirectory(root) || !Files.isWritable(root)) {
    throw new IllegalStateException(
        "XML events root directory not writable: " + root);
}

try {
    launcher.execute(request);
} catch (JUnitException e) {
    if ("Failed to create XML events file".equals(e.getMessage())) {
        Throwable cause = e.getCause();
        // Resolve output dir and either fix permissions or switch junit.platform.reporting.output.dir.
    } else {
        throw e;
    }
}

When it happens

Trigger: The root output directory is read-only, has been deleted, or lives on a full volume at testPlanExecutionStarted time; Events.createDocumentWriter() cannot open the XML file for writing because a file lock is held by another process; the path is on a network mount that dropped; the directory creation succeeded earlier but the volume became unwritable.

Common situations: Read-only container layer for the default build/target dir; CI workspace cleaned between phases; antivirus locking the new XML file on Windows; NFS outage; junit.platform.reporting.output.dir pointing at a path whose parent is not writable.

Related errors

• Failed to create output dir
• Failed to create output file
• Failed to close XML events file
• Error redirecting stderr to file
• Error redirecting stdout and stderr to file

AI-assisted analysis of junit-team/junit5@f070c699a0 (2026-08-11). Data as JSON: /api/errors/55c2760bc913d776. Report an issue: GitHub.

Appendix: source

Thrown at junit-platform-reporting/src/main/java/org/junit/platform/reporting/open/xml/OpenTestReportGeneratingListener.java:167

			NamespaceRegistry namespaceRegistry) throws Exception {
		return config.get(SOCKET_PROPERTY_NAME, Integer::valueOf) //
				.map(port -> {
					try {
						Socket socket = new Socket(InetAddress.getLoopbackAddress(), port);
						Writer writer = new OutputStreamWriter(socket.getOutputStream(), StandardCharsets.UTF_8);
						return Events.createDocumentWriter(namespaceRegistry, writer);
					}
					catch (Exception e) {
						throw new JUnitException("Failed to connect to socket on port " + port, e);
					}
				}) //
				.orElseGet(() -> {
					try {
						Path eventsXml = requireNonNull(outputDir).resolve("open-test-report.xml");
						return Events.createDocumentWriter(namespaceRegistry, eventsXml);
					}
					catch (Exception e) {
						throw new JUnitException("Failed to create XML events file", e);
					}
				});
	}

	private boolean isEnabled(ConfigurationParameters config) {
		return config.getBoolean(ENABLED_PROPERTY_NAME).orElse(false);
	}

	private boolean isGitEnabled(ConfigurationParameters config) {
		return config.getBoolean(GIT_ENABLED_PROPERTY_NAME).orElse(false);
	}

	@SuppressWarnings("EmptyCatch")
	private void reportInfrastructure(ConfigurationParameters config) {
		eventsFileWriter.append(infrastructure(), infrastructure -> {
			try {
				String hostName = InetAddress.getLocalHost().getHostName();
				infrastructure.append(hostName(hostName));

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