随机脚本错误。在 Angular 单元/集成测试中

Question

我有以下问题： 当我使用 Karma 为我的 Angular 项目运行单元/集成测试时，我的测试成功/失败的可能性是 50:50。大多数情况下它可以在我的机器 (:D) 上运行，但不能在我们的构建服务器上运行，这使得它根本不可靠。

当它失败时，它总是一个神秘的错误信息，上面写着

脚本错误。

...仅此而已。现在奇怪的是，它总是另一个失败的测试。

这是我已经做过或看过的：

• https://github.com/karma-runner/karma/issues/1268
• https://github.com/karma-runner/karma/issues/543
• 我没有循环依赖（至少 ng build/serve 没有抱怨）
• 我发现它可能与跨域策略违规有关，但我实际上并没有触发 XHR 或延迟加载其他东西（至少我是这么认为的）

这些是我的依赖项：

"dependencies": {
    "@angular/animations": "^6.0.9",
    "@angular/cdk": "^6.4.0",
    "@angular/common": "^6.0.9",
    "@angular/compiler": "^6.0.9",
    "@angular/core": "^6.0.9",
    "@angular/flex-layout": "^6.0.0-beta.16",
    "@angular/forms": "^6.0.9",
    "@angular/http": "^6.0.9",
    "@angular/material": "^6.4.0",
    "@angular/platform-browser": "^6.0.9",
    "@angular/platform-browser-dynamic": "^6.0.9",
    "@angular/platform-server": "^6.0.9",
    "@angular/router": "^6.0.9",
    "@ngrx/effects": "^6.0.1",
    "@ngrx/router-store": "^6.0.1",
    "@ngrx/store": "^6.0.1",
    "@ngrx/store-devtools": "^6.0.1",
    "core-js": "^2.5.7",
    "devextreme": "^18.1.4",
    "devextreme-angular": "^18.1.4",
    "i": "^0.3.6",
    "jquery": "^3.3.1",
    "ngx-scrollbar": "^2.1.0",
    "node-sass": "^4.9.0",
    "npm": "^6.2.0",
    "rxjs": "^6.2.2",
    "stream": "0.0.2",
    "web-animations-js": "^2.3.1",
    "zone.js": "^0.8.26"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.6.3",
    "@angular/cli": "^6.0.8",
    "@angular/compiler-cli": "^6.0.9",
    "@angular/language-service": "^6.0.9",
    "@types/jasmine": "^2.8.8",
    "@types/jasminewd2": "^2.0.3",
    "@types/node": "^10.5.2",
    "codelyzer": "^4.4.2",
    "fs-extra": "^6.0.1",
    "git-describe": "^4.0.3",
    "gulp": "^4.0.0",
    "gulp-param": "^1.0.3",
    "gulp-run": "^1.7.1",
    "hogan.js": "^3.0.2",
    "husky": "^0.14.3",
    "jasmine-core": "^3.1.0",
    "jasmine-spec-reporter": "^4.2.1",
    "jszip": "^3.1.5",
    "karma": "^2.0.4",
    "karma-chrome-launcher": "~2.2.0",
    "karma-cli": "~1.0.1",
    "karma-coverage-istanbul-reporter": "^2.0.1",
    "karma-jasmine": "^1.1.2",
    "karma-jasmine-html-reporter": "^1.2.0",
    "license-checker": "^20.1.0",
    "lint-staged": "^7.2.0",
    "markdown-include": "^0.4.3",
    "prettier": "^1.13.7",
    "protractor": "^5.3.2",
    "readline-sync": "^1.4.9",
    "run-sequence": "^2.2.1",
    "stylelint": "^9.3.0",
    "stylelint-config-recommended-scss": "^3.2.0",
    "stylelint-config-standard": "^18.2.0",
    "stylelint-scss": "^3.1.3",
    "ts-node": "^6.2.0",
    "tslint": "^5.11.0",
    "tslint-config-prettier": "^1.13.0",
    "typescript": "2.7.2",
    "yargs": "^11.1.0"
  }

接下来我该怎么办？？

感谢每一个提示...谢谢

Answer 1

根据我的经验，很多时候这种随机错误是由于测试留下的脏状态导致其他测试失败。 AFAIK 没有预期或定义 Karma 的默认顺序。 我会尝试注释掉测试的前半部分（二进制搜索样式），看看它是否始终如一地通过。

Answer 2

我终于解决了这个问题。

我不知何故走上了正确的道路并弄清楚了，哪个测试失败了，或者更确切地说是导致其他测试失败。

// causing part in the tests
beforeEach(() => {
   fixture = TestBed.createComponent(FilterSidebarComponent);
   component = fixture.componentInstance;
   component.data = {} as DataClass;
   fixture.detectChanges();
 });

现在的问题是，在组件的订阅中，我调用了 DataClass 类的特定方法：

this.attributeXY.subscribe(event => {
    this.data.reset(); <-- reset() was undefined
    if (event) {
     // do something 
     ...
    }
  })

现在剩下的问题是，为什么空对象的转换在这种情况下不起作用？ 我的期望是，reset() 方法也会被推断出来