Try to add this.

    <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-surefire-plugin</artifactId>
       <version>3.5.2</version>
       <configuration>
          <useModulePath>false</useModulePath>
          <includes>
             <include>**/*.java</include>
          </includes>
       </configuration>
    </plugin>