Fix issue #1218: Arrange, Act, Assert pattern (#1221)

* add AAA pattern

* reformat comment

* use Testing in readme tags in stead of Unit Test

pom.xml

@@ -184,6 +184,7 @@
         <module>combinator</module>
         <module>update-method</module>
         <module>leader-followers</module>
+        <module>arrange-act-assert</module>
     </modules>
 
     <repositories>