有一些依赖项单元测试的模拟服务

Question

我有一个服务MetaDataService

@Injectable()
export class MetaDataService {
  constructor(private dataService: DataService, private storageService: StorageService, private platform: Platform, private router: Router) {
    console.log("MetaData Service initialized..");
  }

我想用jest框架在单元测试中模拟这个服务，我得到了以下错误:无法解析MetaDataService的所有参数：(?，?)；

下面是我的jest配置：

module.exports = {
  "preset": "jest-preset-angular",
  moduleFileExtensions: ["ts", "html", "js", "json", "mjs"],
  extensionsToTreatAsEsm: [".ts"],
  "setupFilesAfterEnv": ["<rootDir>/src/setupJest.ts"],
  "testPathIgnorePatterns": [
    "<rootDir>/node_modules/",
    "<rootDir>/node_modules/(?!@ionic)",
    "<rootDir>/node_modules/(?!@ionic/angular)",
    "<rootDir>/node_modules/(?!@ionic|ngx-socket-io/).+\\.js$",
    "<rootDir>/dist/"
  ],
  "globals": {
    "ts-jest": {
      "tsconfig": "<rootDir>/src/tsconfig.spec.json",
      "stringifyContentPathRegex": "\\.html$",
      astTransformers: {
        before: [
          'jest-preset-angular/build/InlineFilesTransformer',
          'jest-preset-angular/build/StripStylesTransformer',
        ]
      }
    }
  },
  "transform": {
    "^.+\\.(ts|js|mjs|html|svg)$": "babel-jest"
  },
  "moduleNameMapper": {
    "^src/(.*)$": "<rootDir>/src/$1",
    "^app/(.*)$": "<rootDir>/src/app/$1",
    "^assets/(.*)$": "<rootDir>/src/assets/$1",
    "^environments/(.*)$": "<rootDir>/src/environments/$1"
  },
  snapshotSerializers: [
    "jest-preset-angular/build/serializers/no-ng-attributes",
    "jest-preset-angular/build/serializers/ng-snapshot",
    "jest-preset-angular/build/serializers/html-comment"
  ]
};

Answer 1

根据您问题中的评论，MockProvider(MetaDataService)为MetaDataService做了一件事。

但是，它在AccessResourceValidatorPipe上失败了，因为它的依赖项不存在于TestBed中。因此，您需要在TestBed.configureTestingModule调用中添加它们。

或者，为了避免这种依赖问题，您可以使用MockBuilder。它模拟所有依赖项。

beforeEach(() => {
  return MockBuilder(
    TestingComponent,
    [
      ItsModule,

      // only if those two aren't imported in the ItsModule
      ModuleOfMetaDataService,
      ModuleOfAccessResourceValidatorPipe,
    ],
  );
});