Load files in xcode unit tests

When running tests the application bundle is still the main bundle. You need to use unit tests bundle.

Objective C:

NSBundle *bundle = [NSBundle bundleForClass:[self class]];
NSString *path = [bundle pathForResource:@"TestData" ofType:@"xml"];
NSData *xmlData = [NSData dataWithContentsOfFile:path];

Swift 2:

let bundle = NSBundle(forClass: self.dynamicType)
let path = bundle.pathForResource("TestData", ofType: "xml")!
let xmlData = NSData(contentsOfFile: path)

Swift 3 and up:

let bundle = Bundle(for: type(of: self))
let path = bundle.path(forResource: "TestData", ofType: "xml")!
let xmlData = NSData(contentsOfFile: path)