Angular 测角仪试验台的正确使用

在一个基于Angular 8.1.2和Ionic 4的应用程序项目中，我用typescript为一个简单的类编写了单元测试。“npm测试”很好。为了准备更复杂的类和所需的模拟，我改变了代码，以这种方式使用beforeach方法和TestBed对象：

import { CryptHelper, CryptCodeTyp, CryptIOStringTyp } from './cryptHelper';
import { TestBed } from '@angular/core/testing';

describe('CryptHelper', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      declarations: [ CryptHelper ],
      imports: [ ],
      providers: [ CryptHelper ],
    }).compileComponents();
  });

  it('should be created', () => {
    let fixture = TestBed.createComponent(CryptHelper);
    let app = fixture.debugElement.componentInstance;
    expect(app).toBeDefined();
  });
});

这样，我就可以在测试输出中得到错误消息

error properties: Object({ ngSyntaxError: true })
Error: Unexpected value 'CryptHelper' declared by the module 'DynamicTestModule'. Please add a @Pipe/@Directive/@Component annotation.
    at syntaxError (http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:2175:1)
    at http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:19889:1
    at <Jasmine>
    at CompileMetadataResolver.getNgModuleMetadata (http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:19871:1)
    at JitCompiler._loadModules (http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:25582:1)
    at JitCompiler._compileModuleAndAllComponents (http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:25571:1)
    at JitCompiler.compileModuleAndAllComponentsAsync (http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:25533:1)
    at CompilerImpl.compileModuleAndAllComponentsAsync (http://localhost:9876/_karma_webpack_/node_modules/@angular/platform-browser-dynamic/fesm2015/platform-browser-dynamic.js:237:1)
    at TestingCompilerImpl.compileModuleAndAllComponentsAsync (http://localhost:9876/_karma_webpack_/node_modules/@angular/platform-browser-dynamic/fesm2015/testing.js:140:1)
    at TestBedViewEngine.compileComponents (http://localhost:9876/_karma_webpack_/node_modules/@angular/core/fesm2015/testing.js:3118:1)

但这让我想到了这个错误信息：

error properties: Object({ ngSyntaxError: true })
Error: Illegal state: Could not load the summary for directive CryptHelper.
    at syntaxError (http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:2175:1)
    at CompileMetadataResolver.getDirectiveSummary (http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:19729:1)
    at JitCompiler.getComponentFactory (http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:25536:1)
    at CompilerImpl.getComponentFactory (http://localhost:9876/_karma_webpack_/node_modules/@angular/platform-browser-dynamic/fesm2015/platform-browser-dynamic.js:263:30)
    at TestingCompilerImpl.getComponentFactory (http://localhost:9876/_karma_webpack_/node_modules/@angular/platform-browser-dynamic/fesm2015/testing.js:148:1)
    at TestBedViewEngine.createComponent (http://localhost:9876/_karma_webpack_/node_modules/@angular/core/fesm2015/testing.js:3418:1)
    at Function.createComponent (http://localhost:9876/_karma_webpack_/node_modules/@angular/core/fesm2015/testing.js:3000:1)
    at UserContext.<anonymous> (http://localhost:9876/_karma_webpack_/src/app/core/services/cryptHelper.spec.ts:15:27)
    at <Jasmine>

错误属性：对象（{ngSyntaxError:true}）
错误：非法状态：无法加载指令CryptHelper的摘要。
在syntaxError(http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:2175:1）
在CompileMetadataResolver.getDirectiveSummary(http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:19729:1）
在JitCompiler.getComponentFactory(http://localhost:9876/_karma_webpack_/node_modules/@angular/compiler/fesm2015/compiler.js:25536:1）
在CompilerImpl.getComponentFactory(http://localhost:9876/_karma_webpack_/node_modules/@angular/platform browser dynamic/fesm2015/platform browser dynamic.js:263:30）
在TestingCompilerImpl.getComponentFactory中(http://localhost:9876/_karma_webpack_/node_modules/@angular/platform browser dynamic/fesm2015/testing.js:148:1）
在TestBedViewEngine.createComponent上(http://localhost:9876/_karma_webpack_/node_modules/@角度/核心/fesm2015/testing.js:3418:1）
在Function.createComponent(http://localhost:9876/_karma_webpack_/node_modules/@角度/核心/fesm2015/testing.js:3000:1）
在UserContext。(http://localhost:9876/_karma_webpack_/src/app/core/services/cryptHelper.spec.ts:15:27)
在

---

我找到了在声明中写类名的建议。但这让我想到了上面的错误消息。那我错了什么？欢迎提供任何帮助。

假设CryptHelper是一个组件：

    TestBed.configureTestingModule({
        declarations: [ CryptHelper], // Your testing component goes here
        providers: [ // Your component's providers goes here, for example a mocked service
            {
                provide: MyService, useValue: mockMyService
            }
        ],
        imports: [
            // imports from your component, for example MatDialogModule, MatInputModule, MyComponentModule, ...
        ]
    })
    .compileComponents();

---

假设CryptHelper是一个服务：

let cryptHelper: CryptHelper;

beforeEach(() => {
    TestBed.configureTestingModule({
        providers: [CryptHelper],
        imports: [] 
    });

    cryptHelper = TestBed.get(CryptHelper);
});

describe('CryptHelper Service creation', () => {
    it('should be created', inject([CryptHelper], (service: CryptHelper) => {
        expect(service).toBeTruthy();
    }));
});

---

正如您的日志所说，CryptHelper不是一个组件。所以正确的测试方法是将其作为服务使用（如果您希望将其作为DI元素使用）。 下面是一个工作示例：

describe('CryptHelper', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [ CryptHelper ],
    });
  });

  it('should be created', () => {
    let fixture = TestBed.get(CryptHelper);
    let app = fixture.debugElement.componentInstance;
    expect(app).toBeDefined();
  });
});

---

你可以注意到，

TestBed.get

被用来代替

TestBed.createComponent

是一个角度

@组件（{…}）

？是的，它是一个服务。所以你的第二个建议是有效的。：-）还有一个问题。什么时候使用inject有用或需要？由于直接使用

it（'应该创建'，（）=>{…}）也可以。很好：）。关于你的问题，嗯。。。这是我在测试服务时使用的语法，但是您可以这样做（'should be created'，（）=>{const service:MyService=TestBed.get（MyService）；expect（service.toBeTruthy（）}）；我想可能还有其他方法。。。希望有帮助^^^谢谢，我明白了，但与Pedro B的另一个答案相比。测试后，对象夹具已经包含对象。因此，
let app=…
不起作用，因此我将另一个解决方案标记为正确的解决方案。
describe('CryptHelper', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [ CryptHelper ],
    });
  });

  it('should be created', () => {
    let fixture = TestBed.get(CryptHelper);
    let app = fixture.debugElement.componentInstance;
    expect(app).toBeDefined();
  });
});