Angular Karma/Jesmine spyOn创建类型‘“x”“不能赋值给'never’类型的参数

Question

我在下面有一个常量类。当我尝试使用spyOn返回一个不同的值以测试错误情况时，ng测试返回类型为'"retryCount"' is not assignable to parameter of type 'never'.‘的编译时错误参数

有没有办法绕过这个问题？

 export class NConstants {
  public static retryCount: number = 2;
  public static readonly retryDelayInMilliseconds: number = 10000; // ms
  public static readonly retryNotificationDelayInSeconds: number = 50;
}


spyOn(NetworkConstants, 'retryCount').and.returnValue(0);

所有包

    "jasmine-auto-spies": "^4.1.0",
    "jasmine-core": "~3.3.0",
    "jasmine-marbles": "^0.6.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "^3.1.3",
    "karma-chrome-launcher": "~2.2.0",
    "karma-cli": "^2.0.0",
    "karma-coverage-istanbul-reporter": "^2.0.4",
    "karma-firefox-launcher": "^1.1.0",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.0",
    "karma-trx-reporter": "^0.3.0",

Answer 1

您只能对类的方法/函数执行spyOn操作，而不能对实例变量执行操作。

要将其更改为返回0，只需直接修改即可。

NConstants.retryCount = 0;
// do what you want.
// further down the line, you can reset it
NConstants.retryCounter = 2;