Linking error in unit test using URLRequestConvertible - ios

Question

I have a weird problem writing a simple unit test (Xcode 7.2) for a very simple function which makes sure a parameter is added to a URL:
func appendToken(token: String, toRequest request: URLRequestConvertible) throws -> URLRequestConvertible {
var error: NSError?
let modifiedRequest: NSMutableURLRequest
(modifiedRequest, error) = Alamofire.ParameterEncoding.URL.encode(request, parameters: ["token": self.token])
guard error == nil else {
// TODO: handle error
throw error!
}
return modifiedRequest
}
The unit test is like this:
func testTokenAddition() {
let token = "ABCD12345"
let client = MyClass(token: token)
let originalRequest = NSURLRequest(URL: NSURL(string:"http://localhost")!)
do {
let modifiedRequest = try client.appendToken(token, toRequest: originalRequest).URLRequest
XCTAssertTrue(modifiedRequest.URLRequest.URLString.hasSuffix("token=\(token)"))
} catch {
XCTFail()
print(error)
}
}
Obviously this is a very simple test on which I want to build upon (so please don't focus on the actual assertion). But when I try to run the test, I get this linking error:
Undefined symbols for architecture x86_64:
"protocol witness table for __ObjC.NSURLRequest : Alamofire.URLRequestConvertible in Alamofire", referenced from:
SDKitTests.SDKitTests.testTokenAddition (SDKitTests.SDKitTests)() -> () in SDKitTests.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
The function works when I run it from a normal target, so the problem is in the test function, but I'm not clear on how I should be calling it, I run the same code in a non-test class and there was no problem, so I'm a bit puzzled by this. Also the error message is a bit cryptic, from what I've Googled, a witness table is kind of like a vtable for protocols. But I haven't messed with that, the extension to NSMutableURLRequest is implemented in Alamofire, and I'm just using it.
What am I doing wrong? What do I need to do to fix it?

Answer 1

Ensure the Alamofire library is linked with your test target.
You may also need to remove inherit! :search_paths from the test target.