Unit Testing in iOS using swift (Part 2)

Kunal Prasad

26 October 2021

Network Call Check

In the previous part, we have already know how to set up the unit testing in Xcode project & some basic functionality.

Refer: https://mobikul.com/unit-testing-in-ios-using-swift-part-1/

In this blog, we will discuss how to test the Network Call (Asynchronous function).

In-Network call we have to wait until the data will come to its totally Asynchronous function so that we have to wait in method until the result will come for that swift provide “expectation”

With the help of this, we can handle Network call.

Example:

let promise = expectation(description: "Completion handler invoked")

wait(for: [promise], timeout: 5) // it helps to wait in thread.

promise.fulfill() // it completes the overall thread.

let promise = expectation(description: "Completion handler invoked")

wait(for: [promise], timeout: 5) // it helps to wait in thread.

promise.fulfill() // it completes the overall thread.

Here are Some Steps you need to follow this

1: Set up Class.

import XCTest

class CICDAPPTNetworkCall: XCTestCase {
var sut: URLSession!
    
    
    
    override func setUp() {
        super.setUp()
        sut = URLSession(configuration: .default)
    }

    override func tearDown() {
        sut = nil
        super.tearDown()
    }
}

import XCTest

class CICDAPPTNetworkCall: XCTestCase {

var sut: URLSession!

override func setUp() {

super.setUp()

sut = URLSession(configuration: .default)

}

override func tearDown() {

sut = nil

super.tearDown()

}

here we have taken the example through “URLSession”

2: Now Start writing the network class checking method.

Valid URL: https://itunes.apple.com/search?media=music&entity=song&term=abba

here we are checking the URL response is valid or not.

 func testCallToiTunesCompletes() {
        // given
        let url =
            URL(string: "https://itunes.apple.com/search?media=music&entity=song&term=abba")
        let promise = expectation(description: "Completion handler invoked")
        var statusCode: Int?
        var responseError: Error?
        
        // when
        let dataTask = sut.dataTask(with: url!) { data, response, error in
            statusCode = (response as? HTTPURLResponse)?.statusCode
            responseError = error
            promise.fulfill()
        }
        dataTask.resume()
        wait(for: [promise], timeout: 5)
        
        // then
        XCTAssertNil(responseError,"Any String Value")  // it will pass when he get nil value    nil == no issue
        XCTAssertEqual(statusCode, 200)   // it compare the value if equal then no issue.
        
        
        
    }

func testCallToiTunesCompletes() {

// given

let url =

URL(string: "https://itunes.apple.com/search?media=music&entity=song&term=abba")

let promise = expectation(description: "Completion handler invoked")

var statusCode: Int?

var responseError: Error?

// when

let dataTask = sut.dataTask(with: url!) { data, response, error in

statusCode = (response as? HTTPURLResponse)?.statusCode

responseError = error

promise.fulfill()

}

dataTask.resume()

wait(for: [promise], timeout: 5)

// then

XCTAssertNil(responseError,"Any String Value") // it will pass when he get nil value nil == no issue

XCTAssertEqual(statusCode, 200) // it compare the value if equal then no issue.

}

Here we have taken the “expectation” class to hold the network call response.

We have taken two Test checking method

1: XCTAssertNil(responseError,”Any String Value”) . if responseError returns nil then there is no issue.

2: XCTAssertEqual(statusCode, 200) if statusCode == 200 then no issue

if any matches fail then you will get the test fail result.

For checking the error case you just change the URL’s string or Invalid URL & check.

This Is The Introduction Of The Async Network Call & Some Other Tips To Test Valid URL , In next Blog we will talk about the Network request through Alamofire .