Vmeda.Online/src/core/utils/tests/async-instance.test.ts
2024-03-07 16:25:07 +01:00

151 lines
5.3 KiB
TypeScript

// (C) Copyright 2015 Moodle Pty Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import { AsyncInstance, LazyMethodsGuard, asyncInstance } from '@/core/utils/async-instance';
import { expectAnyType, expectSameTypes } from '@/testing/utils';
describe('AsyncInstance', () => {
it('initializes instances lazily', async () => {
const asyncService = asyncInstance(() => new LazyService());
expect(asyncService.instance).toBe(undefined);
expect(await asyncService.hello()).toEqual('Hi there!');
expect(asyncService.instance).toBeInstanceOf(LazyService);
});
it('does not initialize instance for eager properties', async () => {
const asyncService = asyncInstance(() => new LazyService());
asyncService.setEagerInstance(new EagerService());
expect(asyncService.instance).toBeUndefined();
expect(asyncService.answer).toEqual(42);
expect(asyncService.instance).toBeUndefined();
expect(await asyncService.isEager()).toBe(true);
expect(await asyncService.hello()).toEqual('Hi there!');
expect(asyncService.instance).toBeInstanceOf(LazyService);
expect(await asyncService.isEager()).toBe(false);
});
it('initialize instance for forced eager properties', async () => {
const asyncService = asyncInstance(() => new LazyService());
asyncService.setEagerInstance(new EagerService());
asyncService.setLazyOverrides(['isEager']);
expect(await asyncService.isEager()).toBe(false);
});
it('does not return undefined methods when they are declared', async () => {
const asyncService = asyncInstance<LazyService, EagerService>(() => new LazyService());
asyncService.setEagerInstance(new EagerService());
asyncService.setLazyMethods(['hello', 'goodbye']);
expect(asyncService.hello).not.toBeUndefined();
expect(asyncService.goodbye).not.toBeUndefined();
expect(asyncService.isEager).not.toBeUndefined();
expect(asyncService.notImplemented).toBeUndefined();
});
it('guards against missing or invalid instance methods', () => {
// Define interfaces.
interface Eager {
lorem(): void;
ipsum(): void;
}
interface Lazy extends Eager {
foo(): void;
bar(): void;
}
// Test valid method tuples.
expectSameTypes<LazyMethodsGuard<['foo', 'bar'], Lazy, Eager>, ['foo', 'bar']>(true);
expectSameTypes<LazyMethodsGuard<['bar', 'foo'], Lazy, Eager>, ['bar', 'foo']>(true);
expectSameTypes<LazyMethodsGuard<['foo', 'foo', 'bar'], Lazy, Eager>, ['foo', 'foo', 'bar']>(true);
// Test invalid method tuples.
expectSameTypes<LazyMethodsGuard<['foo'], Lazy, Eager>, never>(true);
expectSameTypes<LazyMethodsGuard<['foo', 'bar', 'lorem'], Lazy, Eager>, never>(true);
expectSameTypes<LazyMethodsGuard<['foo', 'bar', 'baz'], Lazy, Eager>, never>(true);
});
it('preserves undefined properties after initialization', async () => {
const asyncService = asyncInstance(() => new LazyService()) as { thisDoesNotExist?: () => Promise<void>};
await expect(asyncService.thisDoesNotExist?.()).rejects.toBeInstanceOf(Error);
expect(asyncService.thisDoesNotExist).toBeUndefined();
});
it('restricts types hierarchy', () => {
type GetInstances<T> = T extends AsyncInstance<infer TLazyInstance, infer TEagerInstance>
? { eager: TEagerInstance; lazy: TLazyInstance }
: never;
type GetEagerInstance<T> = GetInstances<T>['eager'];
type GetLazyInstance<T> = GetInstances<T>['lazy'];
expectSameTypes<GetLazyInstance<AsyncInstance<LazyService>>, LazyService>(true);
expectSameTypes<GetEagerInstance<AsyncInstance<LazyService>>, Partial<LazyService>>(true);
expectSameTypes<GetLazyInstance<AsyncInstance<LazyService, EagerService>>, LazyService>(true);
expectSameTypes<GetEagerInstance<AsyncInstance<LazyService, EagerService>>, EagerService>(true);
// @ts-expect-error LazyService should extend FakeEagerService.
expectAnyType<AsyncInstance<LazyService, FakeEagerService>>();
});
it('makes methods asynchronous', () => {
expectSameTypes<AsyncInstance<LazyService>['hello'], () => Promise<string>>(true);
expectSameTypes<AsyncInstance<LazyService>['goodbye'], () => Promise<string>>(true);
});
});
class EagerService {
answer = 42;
notImplemented?(): void;
async isEager(): Promise<boolean> {
return true;
}
}
class FakeEagerService {
answer = '42';
}
class LazyService extends EagerService {
async isEager(): Promise<boolean> {
return false;
}
hello(): string {
return 'Hi there!';
}
async goodbye(): Promise<string> {
return 'Sayonara!';
}
}