ContentDocument ID: id value of incorrect type: 06AP0000001OoEsMAK: [ContentDocumentId] error in test class

Question

When making a test class I've ran into this assertion failure error. FIELD_INTEGRITY_EXCEPTION, ContentDocument ID: id value of incorrect type: 06AP0000001OoEsMAK: [ContentDocumentId]

Here is my test class code:

@isTest
public class LifeLargeCaseReviewCtrlTest {
public static testmethod void NewLLCRCase() {
            
    Account Acc = new Account();
    Acc.Name = 'Test New LLCR Case';
    upsert Acc;
    
    Contact C = new Contact();
    C.AccountId = Acc.id;
    C.FirstName = 'Test First1';
    C.MiddleName = 'Test Middle1';
    C.LastName = 'Test Last1';  
    upsert C;
    
    Lead leadObj = new Lead();
    leadObj.LastName = 'New Claims Lead';
    upsert leadObj;
    
    Case caseObj = new Case();
    caseObj.ContactId = C.id;
    caseObj.Lead__c = leadObj.id;
        
    Case caseObj1 = new Case();
    caseObj1.ContactId = C.id;
    caseObj1.Lead__c = leadObj.id;
    upsert caseObj1;
    
    List<String> policyList = new List<String>();
    Policy__c pol = new Policy__c();
    upsert pol;
    policyList.add(pol.id);
            
    Master_Product__c mp = new Master_Product__c();
    mp.Name = 'Test';
    mp.Active__c = TRUE;
    upsert mp;
    
    Proposed_Purchase__c propObj = new Proposed_Purchase__c();
    propObj.Case__c = caseObj1.id;
    propObj.Add_to_Contract__c = pol.id;
    upsert propObj;  
    
    ContentVersion contentVersion = new ContentVersion();
    contentVersion.Title = 'Test';
    contentVersion.PathOnClient = 'Test.jpg';
    contentVersion.VersionData = Blob.valueOf('Test Content Data');
    contentVersion.IsMajorVersion = true;
    upsert contentVersion;
    List<ContentDocument> documents = [SELECT Id, Title, LatestPublishedVersionId FROM ContentDocument];
    ContentDocumentLink cdl = new ContentDocumentLink();
    cdl.ContentDocumentId = documents[0].Id;
    cdl.LinkedEntityId = caseObj1.id;
    upsert cdl;
    
    Test.startTest();
    LifeLargeCaseReviewCtrl.getInfo(C.id);
    String returnData = LifeLargeCaseReviewCtrl.createLLCRCase(caseObj, policyList, propObj, cdl.Id);
    Test.stopTest();     
    System.assertEquals('Success', returnData, 'Case was not able to be created.');
  }
}

I'm confused how my Id is of the wrong type, or how to fix this error. Any ideas?

Any help is greatly appreciated, thanks!

edit-

here is picture showing the code coverage:

Answer 1

From your screenshot, looks like the fourth argument to the LifeLargeCaseReviewCtrl.createLLCRCase method should be a ContentDocumentid. Instead you are passing in ContentDocumentLink Id. Change LifeLargeCaseReviewCtrl.createLLCRCase(caseObj, policyList, propObj, cdl.Id); to LifeLargeCaseReviewCtrl.createLLCRCase(caseObj, policyList, propObj, documents[0].Id); in your test class

Answer 2

I'm not sure that inserting a ContentVersion implicitly creates a ContentDocument that has an id that can be used in a cdl's ContentDocumentId field. Try creating one explicitly.

Also, to see what type of object that id is actually of, try calling

 documents[0].Id.getSobjectType().getDescribe().getName()