Mocha's test code using ts-mockito does not work - node.js

Question

mocha + chai + ts-mockito is executing unit-test of the node.js application.
In order to test the Service class, we mock the method of the Repository class which is called in the Service class.
Running will not work as expected.
I expect ErrorDto, but the string "TypeError: Can not read property 'then' of null" will be returned.
Please tell me something is wrong.
Test code.
let mockedRepository: MyRepository = tsmockito.mock(MyRepository);
describe("MyService Test", () => {
it("getAll() test", async () => {
const errorDto = new ErrorDto();
errorDto.addMessage("test message");
tsmockito.when(mockedRepository.getAll()).thenCall(() => {
return new Promise((resolve, reject) => {
reject(errorDto);
});
});
let mockedRepositoryInstance: MyRepository = tsmockito.instance(mockedRepository);
Container.set(MyRepository, mockedRepositoryInstance);
let service = new MyService();
let res = await service.getAll();
// I expect ErrorDto for res,
// but "TypeError: Can not read property 'then' of null" is returned.
if (res instanceof ErrorDto) {
// Do not reach below
let msg = res.getMessages();
expect(msg[0]).to.eql("test message");
} else {
// Test failure
expect(true).to.false;
}
});
});
Service class to be tested
#Service()
export default class MyService {
#Log()
public getAll() {
const repository = Container.get(MyRepository);
return new Promise<MyServiceTreeDto[]>((resolve, reject) => {
repository.getAll()
.then((res: MyTreeDomain[]) => {
const resDto = new Array<MyServiceTreeDto>();
//do something...
resolve(resDto);
}).catch((err) => {
reject(err);
});
});
}
}
Repository class to be mocked
#Service()
export default class MyRepository {
public async getAll(domain: MyDomain): Promise<MyTreeDomain[]> {
try {
let res: MyTreeDomain[] = new Array<MyTreeDomain>();
//do async process
return res;
} catch (err) {
if (err instanceof ErrorDto) {
throw err;
} else {
const errorDto = new ErrorDto();
errorDto.addMessage("error!");
throw errorDto;
}
}
}
}