no not needed but it is used by maven per default. if you have a better plugin you can change it. but i would prefer the defaults.
the maven-surfire-plugin is bound to the test phase of the default lifecycle. the maven-surfire-plugins runs all Tests matches the filename pattern Test*.java, *Test.java und *TestCase.java reside in the directory src/test/java.
for more information have a look at http://maven.apache.org/surefire/maven-surefire-plugin/test-mojo.html
you can verify this on the console output... here is the tailed output of mvn test...:
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ rechnungsverwaltung ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ rechnungsverwaltung ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.447 s
[INFO] Finished at: 2015-10-17T22:36:59+02:00
[INFO] Final Memory: 18M/304M
[INFO] ------------------------------------------------------------------------
Hava a look at the line. there you can see that the maven-surefire-plugin is used
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @
mvn help:effective-pom
to the the plugins which are inherited from the standard pom parent. – eckes