[LOG4J2-495] As a unit test developer, I want a JUnit rule to handle specific external configuration files.

• Type: Story
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0-rc1
• Component/s: API, Core

Environment

Inside any JUnit test that relies on a specific log4j2.xml file. For example, FileConfigTest in core.

• Assignee: Matt Sicker
• Reporter: Matt Sicker
• Created: 12/Jan/14 01:11
• Updated: 09/Mar/16 17:42
• Resolved: 21/Oct/15 05:21

Description

There are many unit tests that have the same boilerplate code over and over again:

    private static final String CONFIG = "...";
    private static LoggerContext ctx;

    @BeforeClass
    public static void setupClass() {
        System.setProperty(ConfigurationFactory.CONFIGURATION_FILE_PROPERTY, CONFIG);
        ctx = (LoggerContext) LogManager.getContext(false);
    }

    @AfterClass
    public static void cleanupClass() {
        System.clearProperty(ConfigurationFactory.CONFIGURATION_FILE_PROPERTY);
        ctx.reconfigure();
        StatusLogger.getLogger().reset();
    }

This sort of pattern can be replaced with a quick implementation of org.junit.rules.ExternalResource like so:

package org.apache.logging.log4j.test.rule;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.config.ConfigurationFactory;
import org.apache.logging.log4j.status.StatusLogger;
import org.junit.rules.ExternalResource;

public class ExternalConfig extends ExternalResource {
    private final String configFileName;
    private LoggerContext ctx;

    public ExternalConfig(String configFileName) {
        this.configFileName = configFileName;
    }

    @Override
    protected void before() throws Throwable {
        System.setProperty(ConfigurationFactory.CONFIGURATION_FILE_PROPERTY, this.configFileName);
        this.ctx = (LoggerContext) LogManager.getContext(false);
    }

    @Override
    protected void after() {
        System.clearProperty(ConfigurationFactory.CONFIGURATION_FILE_PROPERTY);
        this.ctx.reconfigure();
        StatusLogger.getLogger().reset();
    }

    public LoggerContext getContext() {
        return this.ctx;
    }
}

Now, instead of a class using the same @BeforeClass and @AfterClass template, it can use something like the following:

    private static final String CONFIG = "...";

    @ClassRule
    public static ExternalConfig config = new ExternalConfig(CONFIG);

This helps reduce a lot of repeated code. I'll submit a patch that cleans up the unit tests with this in a little while.

Sub-Tasks

• Create Log4j config JUnit rule.: Closed
• Update unit tests to use LoggerContextRule.: Closed