I have an  api class and have to wite test class but test class  is not covering :

class;
public class fileViewController { 
ApexPages.StandardController controller; 
public Boolean httpErrorReceived {get; set;} 
public String respFileString {get; set;} 
public String contentType {get;set;} 

public fileViewController(ApexPages.StandardController controller){ 
this.controller = controller; 
httpErrorReceived = false; 
} 

public void viewFile(){ 
try{ 
Case req = getPortfolioUrl(); 
if(null !=req.Portfolio_Analysis_Report__c && req.View_checkbox_c){ 
String authorizationHeader = 'Bearer ' + PortfolioAnalysisCallouts.getAuthToken(); 

Http http = new Http(); 
HttpRequest request = new HttpRequest(); 
request.setMethod('GET'); 
request.setHeader('Authorization', authorizationHeader); 
request.setEndpoint(req.Portfolio_Analysis_Report__c); 
system.debug('Request==='+request); 

HttpResponse response = http.send(request); 
system.debug('Response==='+response); 
if(response.getStatusCode()==200 || response.getStatusCode()==202){ 
//respFileString = response.getBody(); 
respFileString = EncodingUtil.Base64Encode(response.getBodyAsBlob()); 
contentType = 'application/pdf'; 
}else{ 
respFileString = 'Connection Failed '; 
contentType = 'text/plain'; 
httpErrorReceived = true; 
} 
}else{ 
respFileString = '\"Analysis Report\" is not available'; 
contentType = 'text/plain'; 
httpErrorReceived = true; 
} 
}catch(Exception e){ 
respFileString = 'Connection Failed:"; 
contentType = 'text/plain'; 
httpErrorReceived = true; 
} 
System.debug('respFileString=='+respFileString); 
} 

private Case getPortfolioUrl() { 
return [select 
Id, 
Portfolio_Analysis_Report__c, 
View_checkbox_c 
from Case 
where Id =: ApexPages.currentPage().getParameters().get('id')]; 
} 
private static String getUrl(){ 
URLParameters__c urls = URLParameters__c.getOrgDefaults();//custom setting 
String url = urls.newVal__c; 
return url; 
} 
} 

Mock class:
@isTest 

global class MockHttpResponseGenerator implements HttpCalloutMock { 

global HTTPResponse respond(HTTPRequest req) { 

System.assertEquals('https://example.com', req.getEndpoint()); 
System.assertEquals('GET', req.getMethod()); 


HttpResponse res = new HttpResponse(); 
res.setHeader('Content-Type', 'application/json'); 
res.setBody('{"test":"test1"}'); 
res.setStatusCode(200); 
return res; 
} 
} 

test class: 
@isTest 
public class ViewPortfolioPDFControllerTest { 
public static testMethod void method1() { 


case con = new case(); 
con.Subject = 'Test Subject'; 
con.Initial_Status__c ='Takeovers'; 
con.status='In Progress'; 
con.Total_Assets__c = 0; 
con.Portfolio_Analysis_Report__c= '/services/apexrest/claimApi'; 
con.View_checkbox_c=true; 
insert con; 

Test.setMock(HttpCalloutMock.class, new MockHttpResponseGenerator()); 
Test.startTest(); 

apexpages.currentpage().getparameters().put('Cid' , con.Id); 
ApexPages.StandardController sc = new ApexPages.standardController(con); 
ViewPortfolioPDFController vpc= new ViewPortfolioPDFController(sc); 
vpc.viewPortfolioPDF(); 

Test.stopTest(); 
}

can anyone please help