Umbraco单元测试指南：使用@open-wc/testing测试后台扩展与Lit元素

umbraco-unit-testing by umbraco/umbraco-cms-backoffice-skills

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安装命令

npx skills add https://github.com/umbraco/umbraco-cms-backoffice-skills --skill umbraco-unit-testing

内容管理系统 JavaScript 框架测试

🇨🇳中文介绍

Umbraco 单元测试

概述

使用 @open-wc/testing 对 Umbraco 后台扩展进行单元测试 - 这是一个专为 Web Components 和 Lit 元素设计的测试框架。这是最快且最隔离的测试方法。

使用场景

测试上下文逻辑和状态管理
测试 Lit 元素渲染和 shadow DOM
测试可观察订阅和状态变更
测试控制器和工具函数
开发过程中的快速反馈

文档

@open-wc/testing : https://open-wc.org/docs/testing/testing-package/
Web Test Runner : https://modern-web.dev/docs/test-runner/overview/

设置

依赖项

添加到 package.json：

{
  "devDependencies": {
    "@open-wc/testing": "^4.0.0",
    "@web/dev-server-esbuild": "^1.0.0",
    "@web/dev-server-import-maps": "^0.2.0",
    "@web/test-runner": "^0.18.0",
    "@web/test-runner-playwright": "^0.11.0"
  },
  "scripts": {
    "test": "web-test-runner",
    "test:watch": "web-test-runner --watch"
  }
}

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类型	位置	示例
Libs (底层 API)	`dist-cms/libs/`	`element-api`, `observable-api`
Packages (功能模块)	`dist-cms/packages/`	`core/lit-element`, `core/class-api`

备选方案：基于模拟的方法（更简单）

对于不需要完整 Umbraco 上下文系统的更简单的单元测试，可以完全模拟 Umbraco 导入。这种方法：

避免复杂的导入映射配置
运行更快（无需加载 Umbraco 包）
在真正的隔离环境中测试逻辑
非常适合测试类型、常量和可观察模式

// web-test-runner.config.mjs
import { esbuildPlugin } from '@web/dev-server-esbuild';
import { importMapsPlugin } from '@web/dev-server-import-maps';
import { playwrightLauncher } from '@web/test-runner-playwright';

export default {
  files: 'src/**/*.test.ts',
  nodeResolve: true,
  browsers: [playwrightLauncher({ product: 'chromium' })],
  plugins: [
    esbuildPlugin({ ts: true }),
    importMapsPlugin({
      inject: {
        importMap: {
          imports: {
            // 将 Umbraco 导入映射到本地模拟
            '@umbraco-cms/backoffice/external/lit': '/src/__mocks__/lit.js',
            '@umbraco-cms/backoffice/observable-api': '/src/__mocks__/observable-api.js',
            '@umbraco-cms/backoffice/class-api': '/src/__mocks__/class-api.js',
            // 根据需要添加其他映射
          },
        },
      },
    }),
  ],
};

创建 src/__mocks__/observable-api.js：

export class UmbStringState {
  #value;
  #subscribers = [];

  constructor(initialValue) {
    this.#value = initialValue;
  }

  getValue() { return this.#value; }

  setValue(value) {
    this.#value = value;
    this.#subscribers.forEach(cb => cb(value));
  }

  asObservable() {
    return {
      subscribe: (callback) => {
        this.#subscribers.push(callback);
        callback(this.#value);
        return { unsubscribe: () => {
          const idx = this.#subscribers.indexOf(callback);
          if (idx > -1) this.#subscribers.splice(idx, 1);
        }};
      }
    };
  }

  destroy() { this.#subscribers = []; }
}

创建 src/__mocks__/lit.js：

export const html = (strings, ...values) => ({ strings, values });
export const css = (strings, ...values) => ({ strings, values });
export const nothing = Symbol('nothing');
export const customElement = (name) => (target) => target;
export const state = () => (target, propertyKey) => {};

使用模拟进行测试

import { expect } from '@open-wc/testing';
import { OUR_ENTITY_TYPE } from './types.js';

describe('Entity Types', () => {
  it('should define entity type', () => {
    expect(OUR_ENTITY_TYPE).to.equal('our-entity');
  });
});

每种方法的适用场景

场景	方法
测试类型、常量、纯函数	基于模拟（更简单）
测试可观察状态模式	基于模拟（更简单）
测试带有 shadow DOM 的 Lit 元素	完整的 Umbraco 导入
测试元素间的上下文消费	完整的 Umbraco 导入
测试 UUI 组件	完整的 Umbraco 导入

查看 umbraco-backoffice/examples/tree-example/Client/ 中的 tree-example：

web-test-runner.config.mjs - 基于模拟的配置
src/__mocks__/ - 模拟实现
src/**/*.test.ts - 使用模拟的单元测试

my-extension/
├── src/
│   ├── my-context.ts
│   ├── my-context.test.ts      # 与源代码一起测试
│   ├── my-element.ts
│   └── my-element.test.ts
├── web-test-runner.config.mjs
├── package.json
└── tsconfig.json

import { expect, fixture, defineCE } from '@open-wc/testing';
import { html } from 'lit';

describe('MyFeature', () => {
  beforeEach(async () => {
    // 每个测试前的设置
  });

  afterEach(() => {
    // 每个测试后的清理
  });

  it('should do something', async () => {
    // 准备，执行，断言
  });
});

fixture() - 创建并等待元素：

const element = await fixture(html`<my-element></my-element>`);

// 带有父节点（用于上下文消费）
const element = await fixture(html`<my-element></my-element>`, {
  parentNode: hostElement,
});

defineCE() - 使用唯一标签定义自定义元素：

import { UmbLitElement } from '@umbraco-cms/backoffice/lit-element';

class TestHostElement extends UmbLitElement {}
const testHostTag = defineCE(TestHostElement);

const host = await fixture(`<${testHostTag}></${testHostTag}>`);

expect() - Chai 断言：

expect(value).to.equal(5);
expect(value).to.be.true;
expect(array).to.have.length(3);
expect(element.shadowRoot?.textContent).to.include('Hello');

import { expect, fixture, defineCE } from '@open-wc/testing';
import { UmbLitElement } from '@umbraco-cms/backoffice/lit-element';
import { MyContext } from './my-context.js';

class TestHostElement extends UmbLitElement {}
const testHostTag = defineCE(TestHostElement);

describe('MyContext', () => {
  let hostElement: UmbLitElement;
  let context: MyContext;

  beforeEach(async () => {
    hostElement = await fixture(`<${testHostTag}></${testHostTag}>`);
    context = new MyContext(hostElement);
  });

  it('initializes with default value', (done) => {
    context.value.subscribe((value) => {
      expect(value).to.equal(0);
      done();
    });
  });

  it('increments value', (done) => {
    let callCount = 0;
    context.value.subscribe((value) => {
      callCount++;
      if (callCount === 1) {
        expect(value).to.equal(0);
        context.increment();
      } else if (callCount === 2) {
        expect(value).to.equal(1);
        done();
      }
    });
  });
});

import { expect, fixture } from '@open-wc/testing';
import { html } from 'lit';
import './my-element.js';
import type { MyElement } from './my-element.js';

describe('MyElement', () => {
  let element: MyElement;

  beforeEach(async () => {
    element = await fixture(html`<my-element></my-element>`);
  });

  it('renders with default content', async () => {
    expect(element.shadowRoot?.textContent).to.include('Default Value');
  });

  it('updates display when property changes', async () => {
    element.value = 'New Value';
    await element.updateComplete;
    expect(element.shadowRoot?.textContent).to.include('New Value');
  });
});

测试带有上下文的元素

import { expect, fixture, defineCE } from '@open-wc/testing';
import { html } from 'lit';
import { UmbLitElement } from '@umbraco-cms/backoffice/lit-element';
import { MyContext } from './my-context.js';
import './my-view.js';

class TestHostElement extends UmbLitElement {}
const testHostTag = defineCE(TestHostElement);

describe('MyView', () => {
  let element: MyViewElement;
  let context: MyContext;
  let hostElement: UmbLitElement;

  beforeEach(async () => {
    // 1. 创建宿主元素
    hostElement = await fixture(`<${testHostTag}></${testHostTag}>`);

    // 2. 在宿主上创建上下文
    context = new MyContext(hostElement);

    // 3. 创建元素作为宿主的子元素
    element = await fixture(html`<my-view></my-view>`, {
      parentNode: hostElement,
    });
    await element.updateComplete;
  });

  it('displays value from context', async () => {
    expect(element.shadowRoot?.textContent).to.include('Value: 0');
  });

  it('updates when context changes', async () => {
    context.increment();
    await element.updateComplete;
    expect(element.shadowRoot?.textContent).to.include('Value: 1');
  });
});

UUI 组件使用 shadow DOM，因此事件需要 composed: true：

// 点击按钮
it('button click triggers action', async () => {
  const button = element.shadowRoot?.querySelector('uui-button') as HTMLElement;
  button.dispatchEvent(new MouseEvent('click', { bubbles: true, composed: true }));
  await element.updateComplete;
  expect(element.shadowRoot?.textContent).to.include('clicked');
});

// 切换 uui-toggle
it('toggle changes state', async () => {
  const toggle = element.shadowRoot?.querySelector('uui-toggle') as HTMLElement;
  toggle.dispatchEvent(new Event('change', { bubbles: true }));
  await element.updateComplete;
  expect(element.shadowRoot?.textContent).to.include('toggled');
});

可观察状态行为

重要：状态对象仅在值发生变化时发出：

// 这将发出两次（值不同）
state.setValue(0);
state.setValue(1);

// 这发出一次（相同值 - 无第二次发出）
state.setValue(0);
state.setValue(0);

it('does not go below 0', (done) => {
  let callCount = 0;
  context.count.subscribe((value) => {
    callCount++;
    if (callCount === 1) {
      expect(value).to.equal(0);
      context.decrement(); // 尝试低于 0
      setTimeout(() => {
        expect(callCount).to.equal(1); // 无第二次发出
        done();
      }, 50);
    }
  });
});

完整的上下文测试

import { expect, fixture, defineCE } from '@open-wc/testing';
import { UmbLitElement } from '@umbraco-cms/backoffice/lit-element';
import { html } from '@umbraco-cms/backoffice/external/lit';
import { CounterContext } from './counter-context.js';
import './counter-view.js';

class TestHostElement extends UmbLitElement {}
const testHostTag = defineCE(TestHostElement);

describe('CounterContext', () => {
  let element: UmbLitElement;
  let context: CounterContext;

  beforeEach(async () => {
    element = await fixture(`<${testHostTag}></${testHostTag}>`);
    context = new CounterContext(element);
  });

  it('initializes with 0', (done) => {
    context.counter.subscribe((value) => {
      expect(value).to.equal(0);
      done();
    });
  });

  it('increments', (done) => {
    let callCount = 0;
    context.counter.subscribe((value) => {
      callCount++;
      if (callCount === 1) {
        context.increment();
      } else if (callCount === 2) {
        expect(value).to.equal(1);
        done();
      }
    });
  });

  it('resets to 0', (done) => {
    let callCount = 0;
    context.counter.subscribe((value) => {
      callCount++;
      if (callCount === 1) {
        context.increment();
        context.increment();
      } else if (callCount === 3) {
        context.reset();
      } else if (callCount === 4) {
        expect(value).to.equal(0);
        done();
      }
    });
  });
});

describe('CounterView', () => {
  let element: CounterViewElement;
  let context: CounterContext;
  let hostElement: UmbLitElement;

  beforeEach(async () => {
    hostElement = await fixture(`<${testHostTag}></${testHostTag}>`);
    context = new CounterContext(hostElement);
    element = await fixture(html`<counter-view></counter-view>`, {
      parentNode: hostElement,
    });
    await element.updateComplete;
  });

  it('shows initial value', async () => {
    expect(element.shadowRoot?.textContent).to.include('Count: 0');
  });

  it('reflects changes', async () => {
    context.increment();
    await element.updateComplete;
    expect(element.shadowRoot?.textContent).to.include('Count: 1');
  });
});

# 运行所有单元测试
npm test

# 在监视模式下运行
npm run test:watch

# 运行特定文件
npx web-test-runner src/my-element.test.ts

# 运行覆盖率测试
npx web-test-runner --coverage

导入出现 404 错误

检查导入映射路径。对于 API 使用 dist-cms/libs/，对于功能模块使用 dist-cms/packages/。

确保在测试中使用元素之前导入元素文件：

import './my-element.js'; // 副作用导入会注册元素

元素必须是具有上下文的宿主的子元素：

element = await fixture(html`<my-element></my-element>`, {
  parentNode: hostElement, // 宿主必须具有上下文
});

可观察测试挂起

对异步订阅使用 done() 回调：

it('test', (done) => {
  observable.subscribe((value) => {
    expect(value).to.equal(expected);
    done(); // 发出完成信号
  });
});

updateComplete 未等待

element.value = 'new';
await element.updateComplete; // 必须等待
expect(element.shadowRoot?.textContent).to.include('new');

🇺🇸English

Umbraco Unit Testing

What is it?

Unit testing for Umbraco backoffice extensions using @open-wc/testing - a testing framework designed for Web Components and Lit elements. This is the fastest and most isolated testing approach.

When to Use

Testing context logic and state management
Testing Lit element rendering and shadow DOM
Testing observable subscriptions and state changes
Testing controllers and utility functions
Fast feedback during development

Related Skills

umbraco-testing - Master skill for testing overview
umbraco-msw-testing - Add API mocking to unit tests

Documentation

@open-wc/testing : https://open-wc.org/docs/testing/testing-package/
Web Test Runner : https://modern-web.dev/docs/test-runner/overview/

Setup

Dependencies

Add to package.json:

{
  "devDependencies": {
    "@open-wc/testing": "^4.0.0",
    "@web/dev-server-esbuild": "^1.0.0",
    "@web/dev-server-import-maps": "^0.2.0",
    "@web/test-runner": "^0.18.0",
    "@web/test-runner-playwright": "^0.11.0"
  },
  "scripts": {
    "test": "web-test-runner",
    "test:watch": "web-test-runner --watch"
  }
}

Then run:

npm install
npx playwright install chromium

Configuration

Create web-test-runner.config.mjs in the project root:

import { esbuildPlugin } from '@web/dev-server-esbuild';
import { playwrightLauncher } from '@web/test-runner-playwright';
import { importMapsPlugin } from '@web/dev-server-import-maps';

export default {
  rootDir: '.',
  files: ['./src/**/*.test.ts', '!**/node_modules/**'],
  nodeResolve: {
    exportConditions: ['development'],
    preferBuiltins: false,
    browser: false,
  },
  browsers: [playwrightLauncher({ product: 'chromium' })],
  plugins: [
    importMapsPlugin({
      inject: {
        importMap: {
          imports: {
            '@umbraco-cms/backoffice/external/lit': '/node_modules/lit/index.js',
            // CRITICAL: Use dist-cms, NOT dist/packages
            '@umbraco-cms/backoffice/lit-element':
              '/node_modules/@umbraco-cms/backoffice/dist-cms/packages/core/lit-element/index.js',
            // CRITICAL: libs are at dist-cms/libs/, NOT dist-cms/packages/
            '@umbraco-cms/backoffice/element-api':
              '/node_modules/@umbraco-cms/backoffice/dist-cms/libs/element-api/index.js',
            '@umbraco-cms/backoffice/observable-api':
              '/node_modules/@umbraco-cms/backoffice/dist-cms/libs/observable-api/index.js',
            '@umbraco-cms/backoffice/context-api':
              '/node_modules/@umbraco-cms/backoffice/dist-cms/libs/context-api/index.js',
            '@umbraco-cms/backoffice/controller-api':
              '/node_modules/@umbraco-cms/backoffice/dist-cms/libs/controller-api/index.js',
            '@umbraco-cms/backoffice/class-api':
              '/node_modules/@umbraco-cms/backoffice/dist-cms/packages/core/class-api/index.js',
            // Add other imports as needed
          },
        },
      },
    }),
    esbuildPlugin({
      ts: true,
      tsconfig: './tsconfig.json',
      target: 'auto',
      json: true,
    }),
  ],
  testRunnerHtml: (testFramework) =>
    `<html lang="en-us">
      <head>
        <meta charset="UTF-8" />
      </head>
      <body>
        <script type="module" src="${testFramework}"></script>
      </body>
    </html>`,
};

Import Path Reference

Type	Location	Example
Libs (low-level APIs)	`dist-cms/libs/`	`element-api`, `observable-api`
Packages (features)	`dist-cms/packages/`	`core/lit-element`, `core/class-api`

Common mistake : Using dist/packages instead of dist-cms causes 404 errors.

Alternative: Mock-Based Approach (Simpler)

For simpler unit tests that don't need the full Umbraco context system, mock the Umbraco imports entirely. This approach:

Avoids complex import map configuration
Runs faster (no loading Umbraco packages)
Tests logic in true isolation
Works well for testing types, constants, and observable patterns

Simplified Configuration

// web-test-runner.config.mjs
import { esbuildPlugin } from '@web/dev-server-esbuild';
import { importMapsPlugin } from '@web/dev-server-import-maps';
import { playwrightLauncher } from '@web/test-runner-playwright';

export default {
  files: 'src/**/*.test.ts',
  nodeResolve: true,
  browsers: [playwrightLauncher({ product: 'chromium' })],
  plugins: [
    esbuildPlugin({ ts: true }),
    importMapsPlugin({
      inject: {
        importMap: {
          imports: {
            // Map Umbraco imports to local mocks
            '@umbraco-cms/backoffice/external/lit': '/src/__mocks__/lit.js',
            '@umbraco-cms/backoffice/observable-api': '/src/__mocks__/observable-api.js',
            '@umbraco-cms/backoffice/class-api': '/src/__mocks__/class-api.js',
            // Add others as needed
          },
        },
      },
    }),
  ],
};

Mock Files

Create src/__mocks__/observable-api.js:

export class UmbStringState {
  #value;
  #subscribers = [];

  constructor(initialValue) {
    this.#value = initialValue;
  }

  getValue() { return this.#value; }

  setValue(value) {
    this.#value = value;
    this.#subscribers.forEach(cb => cb(value));
  }

  asObservable() {
    return {
      subscribe: (callback) => {
        this.#subscribers.push(callback);
        callback(this.#value);
        return { unsubscribe: () => {
          const idx = this.#subscribers.indexOf(callback);
          if (idx > -1) this.#subscribers.splice(idx, 1);
        }};
      }
    };
  }

  destroy() { this.#subscribers = []; }
}

Create src/__mocks__/lit.js:

export const html = (strings, ...values) => ({ strings, values });
export const css = (strings, ...values) => ({ strings, values });
export const nothing = Symbol('nothing');
export const customElement = (name) => (target) => target;
export const state = () => (target, propertyKey) => {};

Testing with Mocks

import { expect } from '@open-wc/testing';
import { OUR_ENTITY_TYPE } from './types.js';

describe('Entity Types', () => {
  it('should define entity type', () => {
    expect(OUR_ENTITY_TYPE).to.equal('our-entity');
  });
});

When to Use Each Approach

Scenario	Approach
Testing types, constants, pure functions	Mock-based (simpler)
Testing observable state patterns	Mock-based (simpler)
Testing Lit elements with shadow DOM	Full Umbraco imports
Testing context consumption between elements	Full Umbraco imports
Testing with UUI components	Full Umbraco imports

Working Example

See tree-example in umbraco-backoffice/examples/tree-example/Client/:

web-test-runner.config.mjs - Mock-based configuration
src/__mocks__/ - Mock implementations
src/**/*.test.ts - Unit tests using mocks

Directory Structure

my-extension/
├── src/
│   ├── my-context.ts
│   ├── my-context.test.ts      # Test alongside source
│   ├── my-element.ts
│   └── my-element.test.ts
├── web-test-runner.config.mjs
├── package.json
└── tsconfig.json

Patterns

Basic Test Structure

import { expect, fixture, defineCE } from '@open-wc/testing';
import { html } from 'lit';

describe('MyFeature', () => {
  beforeEach(async () => {
    // Setup for each test
  });

  afterEach(() => {
    // Cleanup after each test
  });

  it('should do something', async () => {
    // Arrange, Act, Assert
  });
});

Key Utilities

fixture() - Create and wait for element:

const element = await fixture(html`<my-element></my-element>`);

// With parent node (for context consumption)
const element = await fixture(html`<my-element></my-element>`, {
  parentNode: hostElement,
});

defineCE() - Define custom element with unique tag:

import { UmbLitElement } from '@umbraco-cms/backoffice/lit-element';

class TestHostElement extends UmbLitElement {}
const testHostTag = defineCE(TestHostElement);

const host = await fixture(`<${testHostTag}></${testHostTag}>`);

expect() - Chai assertions:

expect(value).to.equal(5);
expect(value).to.be.true;
expect(array).to.have.length(3);
expect(element.shadowRoot?.textContent).to.include('Hello');

Testing Contexts

import { expect, fixture, defineCE } from '@open-wc/testing';
import { UmbLitElement } from '@umbraco-cms/backoffice/lit-element';
import { MyContext } from './my-context.js';

class TestHostElement extends UmbLitElement {}
const testHostTag = defineCE(TestHostElement);

describe('MyContext', () => {
  let hostElement: UmbLitElement;
  let context: MyContext;

  beforeEach(async () => {
    hostElement = await fixture(`<${testHostTag}></${testHostTag}>`);
    context = new MyContext(hostElement);
  });

  it('initializes with default value', (done) => {
    context.value.subscribe((value) => {
      expect(value).to.equal(0);
      done();
    });
  });

  it('increments value', (done) => {
    let callCount = 0;
    context.value.subscribe((value) => {
      callCount++;
      if (callCount === 1) {
        expect(value).to.equal(0);
        context.increment();
      } else if (callCount === 2) {
        expect(value).to.equal(1);
        done();
      }
    });
  });
});

Testing Lit Elements

import { expect, fixture } from '@open-wc/testing';
import { html } from 'lit';
import './my-element.js';
import type { MyElement } from './my-element.js';

describe('MyElement', () => {
  let element: MyElement;

  beforeEach(async () => {
    element = await fixture(html`<my-element></my-element>`);
  });

  it('renders with default content', async () => {
    expect(element.shadowRoot?.textContent).to.include('Default Value');
  });

  it('updates display when property changes', async () => {
    element.value = 'New Value';
    await element.updateComplete;
    expect(element.shadowRoot?.textContent).to.include('New Value');
  });
});

Testing Elements with Context

import { expect, fixture, defineCE } from '@open-wc/testing';
import { html } from 'lit';
import { UmbLitElement } from '@umbraco-cms/backoffice/lit-element';
import { MyContext } from './my-context.js';
import './my-view.js';

class TestHostElement extends UmbLitElement {}
const testHostTag = defineCE(TestHostElement);

describe('MyView', () => {
  let element: MyViewElement;
  let context: MyContext;
  let hostElement: UmbLitElement;

  beforeEach(async () => {
    // 1. Create host element
    hostElement = await fixture(`<${testHostTag}></${testHostTag}>`);

    // 2. Create context on host
    context = new MyContext(hostElement);

    // 3. Create element as child of host
    element = await fixture(html`<my-view></my-view>`, {
      parentNode: hostElement,
    });
    await element.updateComplete;
  });

  it('displays value from context', async () => {
    expect(element.shadowRoot?.textContent).to.include('Value: 0');
  });

  it('updates when context changes', async () => {
    context.increment();
    await element.updateComplete;
    expect(element.shadowRoot?.textContent).to.include('Value: 1');
  });
});

Testing UI Interactions

UUI components use shadow DOM, so events need composed: true:

// Clicking buttons
it('button click triggers action', async () => {
  const button = element.shadowRoot?.querySelector('uui-button') as HTMLElement;
  button.dispatchEvent(new MouseEvent('click', { bubbles: true, composed: true }));
  await element.updateComplete;
  expect(element.shadowRoot?.textContent).to.include('clicked');
});

// Toggling uui-toggle
it('toggle changes state', async () => {
  const toggle = element.shadowRoot?.querySelector('uui-toggle') as HTMLElement;
  toggle.dispatchEvent(new Event('change', { bubbles: true }));
  await element.updateComplete;
  expect(element.shadowRoot?.textContent).to.include('toggled');
});

Observable State Behavior

Important : State objects only emit when values change:

// This WILL emit twice (values different)
state.setValue(0);
state.setValue(1);

// This emits ONCE (same value - no second emission)
state.setValue(0);
state.setValue(0);

Testing no-op operations:

it('does not go below 0', (done) => {
  let callCount = 0;
  context.count.subscribe((value) => {
    callCount++;
    if (callCount === 1) {
      expect(value).to.equal(0);
      context.decrement(); // Try to go below 0
      setTimeout(() => {
        expect(callCount).to.equal(1); // No second emission
        done();
      }, 50);
    }
  });
});

Examples

Complete Context Test

import { expect, fixture, defineCE } from '@open-wc/testing';
import { UmbLitElement } from '@umbraco-cms/backoffice/lit-element';
import { html } from '@umbraco-cms/backoffice/external/lit';
import { CounterContext } from './counter-context.js';
import './counter-view.js';

class TestHostElement extends UmbLitElement {}
const testHostTag = defineCE(TestHostElement);

describe('CounterContext', () => {
  let element: UmbLitElement;
  let context: CounterContext;

  beforeEach(async () => {
    element = await fixture(`<${testHostTag}></${testHostTag}>`);
    context = new CounterContext(element);
  });

  it('initializes with 0', (done) => {
    context.counter.subscribe((value) => {
      expect(value).to.equal(0);
      done();
    });
  });

  it('increments', (done) => {
    let callCount = 0;
    context.counter.subscribe((value) => {
      callCount++;
      if (callCount === 1) {
        context.increment();
      } else if (callCount === 2) {
        expect(value).to.equal(1);
        done();
      }
    });
  });

  it('resets to 0', (done) => {
    let callCount = 0;
    context.counter.subscribe((value) => {
      callCount++;
      if (callCount === 1) {
        context.increment();
        context.increment();
      } else if (callCount === 3) {
        context.reset();
      } else if (callCount === 4) {
        expect(value).to.equal(0);
        done();
      }
    });
  });
});

describe('CounterView', () => {
  let element: CounterViewElement;
  let context: CounterContext;
  let hostElement: UmbLitElement;

  beforeEach(async () => {
    hostElement = await fixture(`<${testHostTag}></${testHostTag}>`);
    context = new CounterContext(hostElement);
    element = await fixture(html`<counter-view></counter-view>`, {
      parentNode: hostElement,
    });
    await element.updateComplete;
  });

  it('shows initial value', async () => {
    expect(element.shadowRoot?.textContent).to.include('Count: 0');
  });

  it('reflects changes', async () => {
    context.increment();
    await element.updateComplete;
    expect(element.shadowRoot?.textContent).to.include('Count: 1');
  });
});

Running Tests

# Run all unit tests
npm test

# Run in watch mode
npm run test:watch

# Run specific file
npx web-test-runner src/my-element.test.ts

# Run with coverage
npx web-test-runner --coverage

Troubleshooting

404 errors for imports

Check import map paths. Use dist-cms/libs/ for APIs and dist-cms/packages/ for features.

Element not defined

Ensure you import the element file before using it in tests:

import './my-element.js'; // Side effect import registers element

Context not available

Element must be child of host with context:

element = await fixture(html`<my-element></my-element>`, {
  parentNode: hostElement, // Host must have context
});

Observable tests hang

Use done() callback for async subscriptions:

it('test', (done) => {
  observable.subscribe((value) => {
    expect(value).to.equal(expected);
    done(); // Signal completion
  });
});

updateComplete not waiting

Ensure you await it:

element.value = 'new';
await element.updateComplete; // Must await
expect(element.shadowRoot?.textContent).to.include('new');

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