I'm getting this message on my test method for a custom lookup.  It's also commented in the code above line 56.

It appears to me that I'm using the same concept a the call to save Contact that works.  The code test out fine interactively.

Any clues?  Thanks.

THE TEST METHOD IS:

/* Purpose : This class contains unit tests for the Custom Lookup.
*/
@isTest(seeAllData=true)
private class test_CustomContactLkpCntl {

public static testMethod void test_CustomContactLkpCntl() {

//Use the PageReference Apex class to instantiate a page

PageReference pageRef = Page.CustomContactLookup;

//In this case, the Visualforce page named Custom...Lookup is the starting point of this test method.

Test.setCurrentPage(pageRef);

//Instantiate and construct the controller class.

customContactLookupController controller = new customContactLookupController();

//Instantiate a new controller with all parameters in the page
controller = new customContactLookupController();

contact c = new Contact();

//calling an Action method. Same as calling any other Apex method.
//Normally this is executed by a user clicking a button or a link from the Visualforce
//page, but in the test method, just test the action method the same as any
//other method by calling it directly.

//get parameters to page URL
ApexPages.currentPage().getParameters();

//The .getURL will return the page url the Search method returns.

controller.searchString = null;
// String srchPage = controller.search().getUrl();
// System.assertEquals('/apex/customcontactlookup', srchPage);

//Example of calling the 'setter' method for several properties.
//but in a test method, just call the setter method directly.

controller.Contact.LastName = 'Test Last Name';
controller.Contact.FirstName = 'Test First Name';

String newPage = controller.saveContact().getUrl();

//Verify that the success page displays
System.assertEquals('/apex/customcontactlookup', newPage);

controller.contact.Description = 'Test Desc';
String editPage = controller.saveContact().getUrl();

//Verify that the success page displays
System.assertEquals('/apex/customcontactlookup', editPage);
// Next line ERROR - System.NullPointerException: Attempt to de-reference a null object
String srchPage = controller.search().getUrl();
System.assertEquals('/apex/customcontactlookup', srchPage);

}
}

THE CONTROLLER IS:

public with sharing class CustomContactLookupController {

public CustomContactLookupController(ApexPages.StandardController controller) {

}

public Contact contact {get;set;} // new account to create
public List<Contact> results{get;set;} // search results
public string searchString{get;set;} // search keyword
public Boolean IsNew { get; set; }
public String NewTitle { get; set; }

public CustomContactLookupController() {
contact = new Contact();

IsNew = true;
NewTitle = 'Add';

results = new List<Contact>();
// get the current search string
// chgd to below searchString = System.currentPageReference().getParameters().get('lksrch');
searchString = '';
runSearch();
}

// performs the keyword search
public PageReference search() {
runSearch();
return null;
}

// prepare the query and issue the search command
private void runSearch() {
// TODO prepare query string for complex serarches & prevent injections
results = new List<Contact>();
results = performSearch(searchString);
}

// run the search and return the records found.
private List<Contact> performSearch(string searchString) {

String soql = 'select id, Name, Account.Id, Account.Name, Title, Email from contact';
if(searchString != '' && searchString != null)
soql = soql + ' where name LIKE \'%' + searchString +'%\'';
soql = soql + ' limit 25'; // 100';
System.debug(soql);
return database.query(soql);

}

// save the new contact record
public PageReference saveContact() {
if (IsNew == true)
{
insert contact;
IsNew = false;
NewTitle = '* EDIT New Contact *';
}
else
{
upsert contact;
}

searchString = Contact.FirstName = ' ' + Contact.LastName;
runSearch();
return Page.CustomContactLookup;
}

// used by the visualforce page to send the link to the right dom element
public string getFormTag() {
return System.currentPageReference().getParameters().get('frm');
}

// used by the visualforce page to send the link to the right dom element for the text box
public string getTextBox() {
return System.currentPageReference().getParameters().get('txt');
}


}