Your example is fine, should work without any problem.
Tests Passed: 1 passed in 0,226 s
I have tested it with
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
</dependency>
<dependency>
<groupId>org.powermock</groupId>
<artifactId>powermock-module-junit4</artifactId>
<version>1.5.2</version>
</dependency>