[英]How to mock a decorator function used on method that is used in SUT in JEST
I have a typescript class:我有一个打字稿类:
export class SystemUnderTest {
@LogThisAction('sth was done')
public doSomething() {}
}
As you can see it uses a reflection to execute some decoration function:如您所见,它使用反射来执行一些装饰功能:
export declare function LogThisAction(action: string): (target: any) =>
void;
When I run test in I do not care about the actual impl.当我运行测试时,我不关心实际的实现。 of this decorator function, so I try to mock it like this:这个装饰器函数,所以我尝试像这样模拟它:
myModule = require(./DecoratorFunctions);
myModule.LogThisAction = jest.fn();
But that does not seem to work.但这似乎不起作用。 When I run tests I get:当我运行测试时,我得到:
● Test suite failed to run
TypeError: decorator is not a function
at DecorateProperty (node_modules/reflect-metadata/Reflect.js:553:33)
How to achieve my goal in JEST framework ?如何在 JEST 框架中实现我的目标?
Your decorator is technically a function which is returning another function.从技术上讲,您的装饰器是一个返回另一个函数的函数。
So your mock is not correct and it should return a function, try it with:所以你的模拟不正确,它应该返回一个函数,试试:
myModule = require(./DecoratorFunctions);
myModule.LogThisAction = () => jest.fn();
You can use the您可以使用
jest.mock笑话
to mock the module and the underlying implementation模拟模块和底层实现
jest.mock('./DecoratorFunctions', () => ({ LogThisAction: (item: any) => {
return (target, propertyKey, descriptor) => {
// save a reference to the original method
const originalMethod = descriptor.value as () => Promise<any>;
descriptor.value = async function(...args) {
originalMethod.apply(this, args);
return response;
};
return descriptor;
}; }}));
This will mock the implementation of LogThisAction这将模拟LogThisAction的实现
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