I new to writing unit test and need to test a visualforce page that implements an extended controller. The visualforce page is called from a custom button on a parent object (Audit__c) that passes an ID for the extended controller. The ID is used to query values on the parent used to render fields on the VF page of the child (Auto_Audit_Sample_Policy__c. )

How do I pass ID's into the unit test ? Also, the parent object (Audit__c) contains several checkbox fields that the child object (Auto_Audit_Sample_Policy__c) queries thru the extended controller. For unit testing do I preset these checkbox values in the test utility class or the actual unit test ? 

This is the error message I am getting:
Error Message    System.QueryException: List has no rows for assignment to SObject
Stack Trace    Class.ParentChildExtensionAUTOsample.<init>: line 27, column 1
Class.UnitTest_Audit.testNewSample: line 37, column 1

The URL for the custom button is:
/apex/PROD_Audit_Auto_PolicySample?AccId={!Audit__c.Id}

The VF page uses the following controller extension:
<apex:page standardController="Auto_Audit_Sample_Policy__c"  extensions="ParentChildExtensionAUTOsample" > 

The extended controller code :

public with sharing class ParentChildExtensionAUTOsample {

/*
This code supports the PROD_Audiit_Auto_PolicySample visualforce page.
FUNCTION:
Receives parent ID (accID) passed via commandbutton or custom button on parent related list.
AccId must be passed via URL since we are instantiating a new object reccord which is not saved.
accID is needed to query parent fields that are used on the visualforce page for rendering.
A non list object is used for the SOQL query to the parent. The result set is used in the visualforce page for setting control variables for rendering. 
* we are always passing the parent ID to this query and using LIMIT=1 per salesforce best practices. 
The parent ID is loaded into the related list field on the instanitated object to establish relationship when saved. 
*/

public Audit__c audit{get;set;}
Auto_Audit_Sample_Policy__c record;

String accId;
@TestVisible private Apexpages.StandardController controller; 

public ParentChildExtensionAUTOsample(ApexPages.StandardController standardController)
{
//set sample to current record.
this.record = (Auto_Audit_Sample_Policy__c)standardController.getrecord();
//grab AccID passed in from URL
accID=ApexPages.currentPage().getParameters().get('AccId');
  
 audit= [SELECT Id, Name, Policy_Information__c, Policy_Number__c, Prior_Carrier__c, Expiring_Premium__c, Reinstatement_Information__c, Insured_Location__c, Agent_Information__c, Agent_City__c, Agent_Name__c, 
    Driver_Information__c, Age__c, Gender__c, Marital_Status__c, Named_Insured_Add_Driver__c, Occupation__c, Business_Use__c, Vehicle_Information__c, Model_Year__c, Vehicle_Type__c, ISO_Symbol__c, 
    Annual_Miles__c, Limit_Information__c, Liability_Limits__c, UM_Limits__c, UIM_Limits__c, UM_UIM_Limits__c, PIP_Limits__c, PIP_Deductible__c, APD_Deductible_Vehicle__c, Premium__c, Rating_Information__c, 
    MVR_Violations__c, Policy_Discounts__c, Rating_Tier__c, Credit_Scoring__c, Telematics_UBI__c, Loss_Information__c, CLUE_Report__c, Prior_Carrier_Loss_Experience__c, Company_Loss_Experience__c, Individual_Loss_Detail__c, 
    General_Information__c, Signed_Application__c, Vehicle_Photo_Information__c, Proof_of_Ownership__c, Other_Policies__c, UW_Guidelines_Followed__c, Risk_Management_Standards__c, Personal_Auto_Product__c      
    FROM Audit__c WHERE Id = :ApexPages.currentPage().getParameters().get('AccId') LIMIT 1];

//Load the parent Name (ID) into the Audit field. 
record.Audit__c = audit.Id;
}
}

Heres my unit test:
 

@isTest
private class UnitTest_Audit {
  //Test coverage for Account Creation
  static testmethod void testGetAccount() {
    Account acct = UtilityAudit.getAccount();
    insert acct;
  }

  //Test coverage for Audit Creation
  static testmethod void testGetAudit() {
    Account acct = UtilityAudit.getAccount();
    insert acct;
    Test.startTest();    
    Audit__c audit = UtilityAudit.getAudit(acct.Id);
    insert audit;
    Test.stopTest();
  }

  //Test coverage for New Audit Sample Creation (VF page) 
  static testmethod void testNewSample() {
    //initiate the VF page
    PageReference pageRef = Page.prod_audit_auto_policysample;
    Test.setcurrentPage(pageref);
      
    Account acct = UtilityAudit.getAccount();
    insert acct;
    Audit__c audit = UtilityAudit.getAudit(acct.Id);
    insert audit; 
    Auto_Audit_Sample_Policy__c sample = UtilityAudit.getAuto_Audit_Sample_Policy(audit.Id);
    insert sample;
		//set required fields
        sample.Policy_Number__c = 'sampleTest';
        sample.Insured_ZipCode__c = '99999';
		
    Test.startTest();    
 
    //create standard controller and extended controller instance    
    ApexPages.StandardController sc = new ApexPages.standardController(sample);
    ParentChildExtensionAUTOsample testPage = new ParentChildExtensionAUTOsample(sc);
    
    Test.stopTest();
  }
}

Heres my utility class for testing:

@isTest
public class UtilityAudit {
    
    //build the Account object
    public static Account getAccount() {
        Account acct = new Account();
        acct.Name = 'Unit Test Account';

        return acct;
    }

    //build the Audit object
    public static Audit__c getAudit(Id accountId) {
        Audit__c audit = new Audit__c();
        audit.Cedent_Account_CCA_PS__c = accountId;
        //set grid checkbox values. Used by Auto Sample to render VF page fields
        audit.Policy_Information__c = true;
        audit.Policy_Number__c = true;
                
        return audit;
    }

    //build the Auto Sample object
    public static Auto_Audit_Sample_Policy__c getAuto_Audit_Sample_Policy(Id AccId) {
        Auto_Audit_Sample_Policy__c samplePolicy = new Auto_Audit_Sample_Policy__c();
        samplePolicy.Audit__c = AccId;
        samplePolicy.Policy_Number__c = 'sampleTest';
        samplePolicy.Insured_ZipCode__c = '99999';
        
        return samplePolicy;
    }    
   
    
}