No forking observed with surefire 2.16 despite forkCount being > 1 - maven

Question

Here is my setting:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.18.1</version>
<configuration>
<forkCount>1C</forkCount>
<redirectTestOutputToFile>true</redirectTestOutputToFile>
<reuseForks>true</reuseForks>
<argLine>-Xmx256m</argLine>
</configuration>
</plugin>
And I'm using junit 4.12:
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
<version>4.12</version>
</dependency>
But when launching my tests I can't see any forking going on?
I'm using maven 3.2.5 on linux with JDK 8.

Answer 1

I ran a little debug (mvn -X test) and it turns out that despite using version 4.12 surefire isn't using the junit47 provider, but the junit4 provider. Unfortunately the junit4 provider does not seem to handle forkCount.
Crawling through the documentation I could find the following algo that selects the provider : https://maven.apache.org/surefire/maven-surefire-plugin/examples/junit.html
The parallel attribute must be set in order to activate the junit47 provider (a little counter-intuitive...).
I've created a JIRA for that: https://issues.apache.org/jira/browse/SUREFIRE-1171
Now my config looks like this:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.18.1</version>
<configuration>
<parallel>classes</parallel>
<threadCount>1</threadCount>
<forkCount>1C</forkCount>
<redirectTestOutputToFile>true</redirectTestOutputToFile>
<reuseForks>true</reuseForks>
<argLine>-Xmx256m</argLine>
</configuration>
</plugin>
Edit
Turns out, redirectTestOutputToFile is now rendered useless... I've added a comment to an existing issue : https://issues.apache.org/jira/browse/SUREFIRE-703?focusedCommentId=14653289&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14653289
I came up with the following to have both forks and redirectTestOutputToFile work:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.18.1</version>
<dependencies>
<dependency>
<groupId>org.apache.maven.surefire</groupId>
<artifactId>surefire-junit47</artifactId>
<version>2.18.1</version>
</dependency>
</dependencies>
<configuration>
<forkCount>1C</forkCount>
<redirectTestOutputToFile>true</redirectTestOutputToFile>
<reuseForks>true</reuseForks>
<argLine>-Xmx512m</argLine>
</configuration>
</plugin>