I am writing a test class feed item trigger ,iam getting this error can anyone help me
my trigger is
error:System.DmlException: Insert failed. First exception on row 0; first error: CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY, ChatterPostTrigger: execution of BeforeInsert

caused by: System.QueryException: List has no rows for assignment to SObject

Trigger.ChatterPostTrigger: line 11, column 1: []


@isTest
Public with sharing class ChatterPostTriggerTest {
 static testmethod void testChatterPostTrigger(){ 
Profile pr = [Select Id from Profile where Name='Standard User'];
User u = new User();
        u.Username  ='kiranp@test.com';
        u.LastName  ='John jane';      
        u.Alias     = 'jjhan';
        u.CommunityNickname = 'jhane';    
        u.Email ='kumarp@test.com';
        u.EmailEncodingKey = 'UTF-8';
        u.LanguageLocaleKey = 'en_US';
        u.LocaleSidKey = 'en_US';
        u.TimeZoneSidKey = 'America/Los_Angeles';
        u.ProfileId = pr.Id;
        insert u;
        
        // Inserting  feedItems list
        List<FeedItem> feedItems = new List<FeedItem>();
        FeedItem f = new FeedItem();
        f.Body = 'This is test class';
        f.ParentId = u.Id;
        f.ContentDescription = 'this is test class for feed item';
        f.ContentFileName ='test file';
        f.Title ='test class';
        f.Type = 'PollPost';
        feedItems.add(f);
        insert feedItems;
        
        //Collabaration Group Insertion
        List<CollaborationGroup> collabarationgroup = new List<CollaborationGroup>();
         CollaborationGroup   CG = new CollaborationGroup();
         CG.Description = 'This is Collabarationgroup' ;
         CG.Name ='MYGroup';
         
         collabarationgroup.add(CG);
         insert collabarationgroup;
         
         // Collabaration Group Member Insertion
          List<CollaborationGroupMember> cgm = new  List<CollaborationGroupMember>();
          CollaborationGroupMember CGMember = new CollaborationGroupMember();
          //CGMember.CollaborationGroupId = CollaborationGroup.Id;
         // CGMember.MemberId = CollaborationGroup.Id;
         CGMember.CollaborationRole ='Standard';
          cgm.add(CGMember);
          insert cgm;  
         
        }
        }