Unit Testing a method that uses REST calls in Swift

Question

Let me start out by stating I'm still unfamiliar with what I'm trying to do, but striving to get better!

I'm working on a project that I'm writing unit tests for and I'm having some trouble with how to approach the problem.

The method I'm testing utilizes a RESTAPI call to verify a users credentials. I'm not sure what the best way to unit test would be.

Here is the method I'm looking to make the Unit test for:

@IBAction func loginBtnActivate(sender: UIButton) {
    let enteredEmail: String = emailField.text!
    let enteredPassword: String = passwordField.text!
    let testInfo:[String: AnyObject] = ["User": enteredEmail, "Password": enteredPassword]
    RestApiManager.sharedInstance.postLogin(testInfo) { (json, statusCode) in
        if statusCode == 200 {
            let AuthToken: TokenObject = (TokenObject(json: json))
            try! self.keychain.set(AuthToken.Authorization, key:"Authorization")
            try! self.keychain.set(AuthToken.LifeTime, key: "LifeTime")
            try! self.keychain.set(AuthToken.UUID, key: "UUID")
             NSOperationQueue.mainQueue().addOperationWithBlock {
                self.performSegueWithIdentifier("loginToMyHealth", sender: nil)
            }
        } else if statusCode == 401 {
            self.incorrectLoginAlert()
        } else if statusCode == 503 {
            print("Service Unavailable Please Try Again Later")
        }
    }
}

This is currently the approach I'm taking:

 func testLoginInfoMatchesDataOnServer(){
    let enteredEmail: String = "user"
    let enteredPassword: String = "password"
    let testInfo:[String: AnyObject] = ["User": enteredEmail, "Password": enteredPassword]
    RestApiManager.sharedInstance.postLogin(testInfo) { (json, statusCode) in
    XCTAssert(statusCode == 200, "statusCode is not matching the server data")
}

I'm simply verifying that the Rest call is successful and that the credentials are matching the JSON. The XCTAssert call doesn't appear to be working correctly. No matter what I put as the first parameter, XCTAssert doesn't affect whether the test is successful or not.

Example, if I put:

XCTAssert(false, "statusCode is not matching the server data")

The test will still pass regardless of what I put. If I place the Assert function outside the brackets then it appears the variable "statusCode" is out of scope so I'm stuck with a

Use of unresolved identifier 'statusCode'.

   func testLoginInfoMatchesDataOnServer(){
let enteredEmail: String = "user"
let enteredPassword: String = "password"
let testInfo:[String: AnyObject] = ["User": enteredEmail, "Password": enteredPassword]
RestApiManager.sharedInstance.postLogin(testInfo) { (json, statusCode) in
}
XCTAssert(statusCode == 200, "statusCode is not matching the server data")
}

I was looking at this guide for help.. Would this be a better approach for what I'm trying to do?

http://roadfiresoftware.com/2016/06/how-do-you-unit-test-rest-calls-in-swift/

Again my understanding of some core concepts might be entirely off so I really appreciate your advice here!

Thanks in advance!

Sean W.

Answer 1

First Few problems with your code

function test(){    
    RestApiManager.sharedInstance.postLogin(testInfo) { (json, statusCode) in

    }//PostLogin call ends
    XCTAssert(statusCode == 200, "statusCode is not matching the server data") // Here StatusCode is not accessible as outside the block
}// end function

If you want to use Status Code you should do

function test(){    
    RestApiManager.sharedInstance.postLogin(testInfo) { (json, statusCode) in
        XCTAssert(statusCode == 200, "statusCode is not matching the server data") // Here StatusCode is accessible inside the block
    }//PostLogin call ends
}// end function

But this will fail since you need to wait for the response. That can be done using

waitForExpectationsWithTimeout(5)

So proper way to call this would be --

function test(){    
    let URL = NSURL(string: "http://google.com/")!
    let expectation = expectationWithDescription("GET \(URL)")
    RestApiManager.sharedInstance.postLogin(testInfo) { (json, statusCode) in
        XCTAssert(statusCode == 200, "statusCode is not matching the server data") // Here StatusCode is accessible inside the block
        expectation.fulfill()
    }//PostLogin call ends
    waitForExpectationsWithTimeout(5){ error in 
        if let error = error {
            print("Error: \(error.localizedDescription)")
        }
    }//Wait block end
}// end function

Important lines here are

expectation.fulfill() // tells process is complete

and

waitForExpectationsWithTimeout(5){} //tells wait for 5secs or throw error

For more info