Apex Invocable Class with multiple variables/parameters

InvocableMethod.cls

global class InvocableMethodcls {

    /*An invocable variable used as input or output variables in the process builder*/
    global class ActionRequest {
        @InvocableVariable(required = true)
        public ID leadId;

        @InvocableVariable
        public String phone;

        @InvocableVariable
        public String email;

        @InvocableVariable
        public Lead leadObj;

        @InvocableVariable
        public String firstName;

        @InvocableVariable
        public String lastName;
    }
    //This invocable method is used for processing the business by taking the input from process builder
    @InvocableMethod(label = 'Invoke Business Logic')
        global static void invokeService(List < ActionRequest > requests) {
          for (ActionRequest requestObj: requests) {
              //Accessing the values from process builder when record is inserted
              System.debug('requestObj.leadId@@:' + requestObj.leadId);
              System.debug('requestObj.firstname@@:' + requestObj.firstname);
              System.debug('requestObj.lastname@@:' + requestObj.lastname);
          }
          //We can write our own business logic herer.
    }
}

InvocableMethod_Test.cls

@isTest
public class UpdateFieldActionTests {

    @isTest
    public static void InvocableMethod_Success(){
        
        // arrange
        final String firstName = 'John';
        final String lastName = 'Wick';
        final String phone = '1112223333';
        final String email = '[email protected]';
        Lead lead = new Lead();
        lead.lastName = lastName;
        lead.email = email;
        insert lead;
                
        InvocableMethodcls.ActionRequest request = new InvocableMethodcls.ActionRequest();
        
        request.leadId = lead.Id;
        request.phone = phone;
        request.firstName = firstName;
        request.lastName = lastName;
        request.email = email;
        request.leadObj = lead;
        
        // act
        InvocableMethodcls.updateFields(new List<InvocableMethodcls.ActionRequest> {request});
        // Your Logic 
        /*
          Lead updatedLead = [SELECT Id, lastName FROM Lead WHERE Id = :lead.Id];

          // assert
          System.assertEquals(lead.lastName, updatedLead.lastName);
        */
    }    
}