fix: Constructor Injection fail in vitest/jest

[zhangfisher]

Description

Constructor Injection fail in vitest/jest
Injected with instance ContainerInstance

import 'reflect-metadata';
//import {expect, test} from "vitest"
import {expect, test} from '@jest/globals';
import { Container, Inject, Service,  ServiceOptions, Token } from 'typedi';
import { FlexEvent } from 'flex-tools'; 
    
@Service({
    id:"app",
    global:true,
    eager:true
})
class App extends FlexEvent{    
    constructor(
        @Inject(WORKSHOP)
        public workshop:Workshop 
    ){
        super()
}
        

@Service({
    id:"app",
    global:true,
    eager:true
})
class App extends FlexEvent{    
    constructor(
        @Inject(WORKSHOP)
        public workshop:Workshop 
    ){
        super()
 //     workshop === Injected with instance ContainerInstance
        
    }
}

test("构造注入", () => {  
    let app = Container.get("app")  as App
    expect(app.workshop).toBeInstanceOf(Workshop)
})

Expected behavior

Injected with instance Workshop

Actual behavior

Injected with instance Workshop ContainerInstance

[abhayshiravanthe]

We found out that when you are using Jest and TypeDI, using @Inject tag doesn't actually inject dependencies into the class during test execution. A workaround would be to manually add dependency resolution in the class constructor, for example:

class SomeClass {

  constructor() {
    // Why - for resolvers or classes where Jest can't resolve the injected services
    this.emailService = Container.get(EmailService);
  }

}

[zhangfisher]

This is not a solution
Due to the inability to inject through construction, if unit testing is required, construction injection can only be abandoned.

[mt3o]

The microsofts DI for typescript, tsyringe, can prepare a separate constructor that hides injections within it and wraps the actual constructor.