surefire 3.0.0-M4 problem

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.teamtter.fake</groupId>
	<artifactId>test-fake-module</artifactId>
	<version>2.0.0-SNAPSHOT</version>

	<properties>
		<java.source.target.version>1.8</java.source.target.version>
		<surefire.version>3.0.0-M3</surefire.version>
	</properties>

	<build>

		<plugins>

			<plugin>
				<groupId>ru.yaal.maven</groupId>
				<artifactId>write-text-files-maven-plugin</artifactId>
				<version>1.1</version>
				<configuration>
					<charset>UTF-8</charset>
					<files>
						<file>
							<path>src/test/java/com/teamtter/AppTest.java</path>
							<lines>
								<line>package com.teamtter;			</line>
								<line>import org.junit.Assert;      </line>
								<line>import org.junit.Test;		</line>
								<line>public class AppTest {		</line>
								<line>	@Test						</line>
								<line>	public void toto() {		</line>
								<line>		String envPath = System.getenv("PATH");</line>
								<line>		System.out.println("envPath = " + envPath);</line>
								<line>		String envLDPath = System.getenv("LD_LIBRARY_PATH");</line>
								<line>		System.out.println("envLDPath = " + envLDPath);    </line>
								<line>		Assert.assertTrue(envPath.contains("TEST"));       </line>
								<line>	}</line>
								<line>}</line>
							</lines>
						</file>
					</files>
				</configuration>
				<executions>
					<execution>
						<id>write-text-files</id>
						<phase>validate</phase>
						<goals>
							<goal>write-text-files</goal>
						</goals>
					</execution>
				</executions>
			</plugin>

			<plugin>
				<artifactId>maven-surefire-plugin</artifactId>
				<version>${surefire.version}</version>
<!-- 				<version>3.0.0-M4</version> -->
				<!-- <version>3.0.0-M3</version> -->
				<!-- <version>2.22.0</version> -->
				<configuration>
					<environmentVariables>
						<LD_LIBRARY_PATH>MY_REDEFINED_LD_PATH</LD_LIBRARY_PATH>
						<PATH>TEST;${PATH}</PATH>
					</environmentVariables>
					<!-- <argLine>@{argLine} -Dfile.encoding=UTF-8</argLine> -->
					<argLine>-Dfile.encoding=UTF-8</argLine>
					<includes>
						<include>**/*.java</include>
					</includes>
				</configuration>
			</plugin>

		</plugins>
	</build>

	<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.11</version>
			<scope>test</scope>
		</dependency>
	</dependencies>

</project>

This pom.xml demonstrates that surefire 3.0.0-M4 has a problem: it does not redefines environment variable if they are already defined. PATH is always defined and shows the problem. It works with 3.0.0-M3
This command first succeeds but then fails with 3.0.0-M4:
mvn test -Dsurefire.version=3.0.0-M3 && mvn test -Dsurefire.version=3.0.0-M4