unit testing - Spock - @Subject annotation and util | helper class that's being tested -

i got question regarding convention of tests in spock.

let got a class test, util class static methods. classic way test it, a.method() in each test method.

however, in spock got @subject annotation (and groovy let that, if said class has private constructor) , began wondering.

@subject util = new a() 

and later in tests call methods util.method().

by doing that, achieve cleaner test. instantly see what's being tested. in ides highlighted , so. @subject verbose annotation.

do see cons of doing tests such way? or there better way clealny test util classes in spock?

i see advantage of having verbose @subject, instantiating utility class can cause more confusion.

there check intellij instantiation of utility class:

reports new expressions instantiate utility classes. utility classes have fields , methods declared static, , presence may indicate lack of object-oriented design. instantiation of such classes indicates programmer error.

• it's unnatural , might considered programming mistake other developers
• disobeying private keyword bad practice
• sonar, codenarc , intellij complain

i go classic approach or avoiding utility classes @ all. it's convention though.