I've attempted to create a before delete trigger on the Contact object that will disallow deletion if an Activity (Event or Task) exists for that Contact. If there are no Activities, the Contact will be deleted, along with any associated Production Memberships (custom object). The trigger works on an individual basis using the UI, but I'm not returning the expected amount of rows after deletion in my test class. Unfortunately, I'm too green to know if the error lies in my trigger or my test. Any help would be appreciated. Thanks!

Here's my trigger:

trigger beforeContactDelete on Contact (before delete) {

	//Create Set of Contacts from trigger
	
	Set<ID> contactIDs = new Set<ID>();
	
	for (Contact c : Trigger.old) {
		
		contactIDs.add(c.ID);

	}

	//All activities tied to a Contact in the trigger
	
	Set<ID> allActivities = new Set<ID>();
	
	for (Event e : [SELECT WhoId FROM Event WHERE WhoId IN : contactIDs]) {
		
		allActivities.add(e.WhoId);
		
	}
	
	for (Task t : [SELECT WhoId FROM Task WHERE WhoId IN : contactIDs]) {
		
		allActivities.add(t.WhoId);
		
	}
	
	//All Contacts with activities
	
	Set<ID> dirtyContacts = new Set<ID>();

	for (Contact c : [SELECT ID FROM Contact WHERE ID IN : allActivities]) {
		
		dirtyContacts.add(c.ID);
			
	}
	
	//Create set of Contacts from trigger without activities
	
	Set<ID> cleanContacts = new Set<ID>();
	
	cleanContacts.addAll(contactIDs);
	cleanContacts.removeAll(dirtyContacts);
	
	//Create List of Production Memberships tied to a clean Contact
	
	List<Production_Member__c> productionMemberships = [SELECT ID FROM Production_Member__c WHERE Contact__c IN : cleanContacts];
	
	//Delete the contact and the Production Member
	
 	for (Contact c : Trigger.old) {
 		
 		if(Trigger.isBefore) {
 		
	 		if(Trigger.isDelete) {
	 			
	 			if(dirtyContacts.containsAll(Trigger.oldMap.keySet())) {
	 				
	 				c.addError('This contact has an activity and therefore cannot be deleted');
	 				
	 			} else if(cleanContacts.containsAll(Trigger.oldMap.keySet())) {
	 				
	 				if(productionMemberships != null) {
	 					
	 					delete productionMemberships;
	 					
	 				}
	 				
	 			}

	 		}
 		
 		}
 		
 	}

}

Here's the test class:

@isTest
private class testBeforeContactDelete {

    static testMethod void bulkContactDeleteTest() {

		//Create the list of contacts to test delete
		
		List<Contact> testContacts = [SELECT ID FROM Contact WHERE Account.Name = 'contactTest'];
		
		//Start Contact Delete Trigger
		
		Test.startTest();
		
		delete testContacts;
		
		Test.stopTest();
		
		//Check for desired results
		
		List<Contact> deletedContacts = [SELECT ID FROM Contact WHERE Account.Name = 'contactTest'];

		List<Production_Member__c> deletedPMs = [SELECT ID FROM Production_Member__c WHERE Contact__r.Account.Name = 'contactTest'];

    }
}