Sample iOS Unit Tests: Testing Model Class methods

Sample iOS Unit Tests: Testing Model Class methods

// 

// TEST CODE

import XCTest
@testable import to

class JSONReaderTest: XCTestCase {
    
    let systemUnderTest = JSONReader()
    
    override func setUp() {
        
        super.setUp()
    }
    
    func testSUT_CanInstantiateJSONReader() {

        XCTAssertNotNil(systemUnderTest)
    }
  
    func testSUT_CanFetchJSONFileFromMainBundleAsString() {
        
        let dataAsString = systemUnderTest.fetchJSONAsStringFromMainBundleWithFileName("results")
        let numberOfCharacters = dataAsString.characters.count
        XCTAssertGreaterThan(numberOfCharacters, 0)
    }
    
    func testSUT_CanHandleFileNotFoundWhenFetchingString() {
        
        let nameOfFileNotInBundle = "nofile"
        let dataAsString = systemUnderTest.fetchJSONAsStringFromMainBundleWithFileName(nameOfFileNotInBundle)
        let numberOfCharacters = dataAsString.characters.count
        XCTAssertEqual(numberOfCharacters, 0)
    }
}

// PRODUCTION CODE

import Foundation

struct JSONReader {
    
    /**
     For fetching a JSON file stored in the main bundle and returning it as a String.
     
     - Parameters: 
        - fileName: The name of the file to fetch.
     
     - Returns: A string representation of the JSON file.
    */
    func fetchJSONAsStringFromMainBundleWithFileName(fileName: String) -> String {

        if let filepath = NSBundle.mainBundle().pathForResource(fileName, ofType: "json") {
            
            do {
            
                return try NSString(contentsOfFile: filepath, usedEncoding: nil) as String
            }
            catch let error as NSError {
                
                print(error.localizedDescription)
                return String()
            }
        }
        else {
            
            return String()
        }
    }
}