2019独角兽企业重金招聘Python工程师标准>>> 
##8.1数字格式设置（storyboard） 
##8.1.2可选类型拆封
import Cocoa
extension Double{var dollars : String{let formatter : NumberFormatter = NumberFormatter()//NSNumberFormatter弃用var result : String?//将result的类型声明为可选类型formatter.numberStyle = .currencyresult = formatter.string(from: NSNumber(value:self))
// .string(from: NSNumber)返回为可选类型，因为如果转换失败会返回nilif (result == nil){return "FORMAT FAILURE!"}return result!//拆封可选变量，拆封指的是将变量转换为值不能为nil的变量}}
class ViewController: NSViewController {//"!"为隐式封拆的可选类型，相当于告诉编译器，在该变量为nil时绝不会访问它@IBOutlet weak var loanAmountField :NSTextField!@IBOutlet weak var interestRateField : NSTextField!@IBOutlet weak var yearsField : NSTextField!@IBOutlet weak var resultsField : NSTextField!var simpleInterestCalculator : SimpInterest = SimpInterest()var compoundInterestCalculator : CompoundInterest = CompoundInterest()override func viewDidLoad() {super.viewDidLoad()}override var representedObject: Any? {didSet {}}[@IBAction](https://my.oschina.net/u/866341) func buttonClicked(sender : NSButton){var result : Doubleresult = simpleInterestCalculator.calculate(loanAmount: loanAmountField.doubleValue, interestRate: interestRateField.doubleValue , years: yearsField.integerValue)
// self.resultsField.stringValue = result.description//description让类能够返回其数据的String表示self.resultsField.stringValue = result.dollars}@IBAction func compoundbuttonClicked(_ sender: NSButton) {var result : Doubleresult = compoundInterestCalculator.calculate(loanAmount: loanAmountField.doubleValue, interestRate: interestRateField.doubleValue , years: yearsField.integerValue)// self.resultsField.stringValue = result.description//description让类能够返回其数据的String表示self.resultsField.stringValue = result.dollars}
}8.2单元测试 if Use of undeclared type 'SimpInterest' take class Target Membership choose
import XCTestclass MACSwiftTeststwo: XCTestCase {var mySimpInterestCalculator : SimpInterest = SimpInterest()var myCompoundInterestCalculator : CompoundInterest = CompoundInterest()override func setUp() {super.setUp()// Put setup code here. This method is called before the invocation of each test method in the class.//在这里插入设置代码，调用这个类中的每个测试方法前，都将调用这个方法}override func tearDown() {// Put teardown code here. This method is called after the invocation of each test method in the class.//在这里插入清理代码，调用这个类中的每个测试方法后，都将调用这个方法super.tearDown()}//功能测试用例func testSimpleInterest(){var result : Doubleresult = mySimpInterestCalculator.calculate(loanAmount: 25_000, interestRate: 0.08, years: 10)XCTAssertEqualWithAccuracy(result,45000,accuracy:0.1 ,"Unexpected result \(result)")//1.要评估的变量 2.该变量应包含的值 3准确因子 4.未通过测试时显示的String//传入的变量和预期结果相差不超过0.1}func testCompoundInterest(){var result : Doubleresult = myCompoundInterestCalculator.calculate(loanAmount: 25_000, interestRate: 0.08, years: 10)XCTAssertEqualWithAccuracy(result, 25002+0.1, accuracy: 0.1,"Unexpected result \(result)")}//示例测试方法
// func testExample() {
// // This is an example of a functional test case.
// // Use XCTAssert and related functions to verify your tests produce the correct results.
// }
//
// func testPerformanceExample() {
// // This is an example of a performance test case.
// self.measure {
// // Put the code you want to measure the time of here.
// }
// }}
