How to override log4j.properties during testing?

I'm trying to log all DEBUG messages to console during testing in maven. For this purpose I created a file src/test/resources/log4j.properties, which is going to override the configuration I already have in src/main/resources/log4j.properties. Unfortunately such an overriding is not happening. Why and how to fix i开发者_运维问答t?

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Rename your test configuration file to e.g. log4j-surefire.properties and configure log4j to pick it up during surefire execution:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.6</version>
    <configuration>
        <systemPropertyVariables>
            <log4j.configuration>file:${project.build.testOutputDirectory}/log4j-surefire.properties</log4j.configuration>
        </systemPropertyVariables>
    </configuration>
</plugin>

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It should work as it is, and it works. The problem is somewhere else.

ps. I had a mess with loggers in my classpath: jog4j, slf4j, logback (from other dependencies). As I understand, all of them are in conflict. I didn't clean this mess yet, and I still don't know how to make all packages to use one logging facility and one configuration.

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Beware of changed version for that, with 2.17.1 of log4j at least, you'll have to change it from log4j.configuration to log4j.configurationFile to avoid having

ERROR StatusLogger Reconfiguration failed: No configuration found for '18b4aac2' at 'null' in 'null'

Here an example

        <plugin>
            <!--            DOC http://maven.apache.org/surefire/maven-surefire-plugin/test-mojo.html -->
            <artifactId>maven-surefire-plugin</artifactId>
            <version>${maven.surefire.version}</version>
            <!-- enables java assertions for tests -->
            <configuration>
                <enableAssertions>true</enableAssertions>
                <systemPropertyVariables>
                    <log4j.configurationFile>src/test/resources/log4j2_for_surefire.xml</log4j.configurationFile>
                </systemPropertyVariables>
            </configuration>
        </plugin>