Union & HCEs excluded for Safe Harbor

The plan excludes Union employees for the employer contribution including safe harbor. The plan is opted for safe harbor non elective and HCEs are excluded for the SH Non Elective. The plan has totally 4 HCEs (2 union and 2 non union employees) and 2 NHCEs and both are Union employees. 

None of the employees received the SHNE contribution. Whether the plan is subjected to ADP for union employees and ADP ACP for non union employees if the additional employer match is allocated.

My understanding is the plan is deemed to pass since the exclusion is not discriminate in nature against NHCEs and both of them are not received the contribution. Is there any other opinion on this.

The Union portion of the Plan does have ADP testing first of all.  The Union is not covered by the safe harbor so ADP testing is required.  Union plans are exempt from ACP testing altogether (the collective bargaining process is the protection for the NHCE's on the match).

For the non-union, you have no NHCEs and so all testing is passed by default.  You can go hog wild, 415 max for everyone, and there's not a darn thing in the Internal Revenue Code to stop you.