如何确保Jasmine测试时Three.js Geometry已完成异步加载？

Ah, I’ve run into this exact timing issue before—async dependencies throwing off test execution is such a common gotcha in Jasmine! The key here is to leverage Jasmine’s built-in support for asynchronous operations in your beforeAll hook, so it waits until Geometry is fully loaded before running any test cases.

Here are the most reliable approaches depending on how your Geometry loading is implemented:

1. Using the done Callback (for callback-based loading) #

If your Geometry loading uses a traditional callback pattern, pass the done parameter to beforeAll and call it once the Geometry is ready. This tells Jasmine to pause execution until done() is invoked.

describe("Model Class", function() {
  var geometry;

  beforeAll(function(done) {
    // Replace with your actual Geometry loading logic
    loadGeometry(function(loadedGeometry) {
      geometry = loadedGeometry;
      // Signal Jasmine the async operation is complete
      done();
    });

    // Add error handling to avoid hanging tests
    // Example: if loadGeometry has an error callback
    // loadGeometry(geo => { ... }, error => done.fail(error));
  });

  it("should have Geometry loaded successfully", function() {
    expect(geometry).toBeDefined();
    // Your other test assertions here
  });
});

2. Returning a Promise (for promise-based loading) #

If your Geometry loading returns a Promise (modern approach), simply return that Promise from beforeAll. Jasmine will automatically wait for it to resolve before running tests. You can also use async/await for cleaner code (supported in Jasmine 2.7+).

Promise.then() version: #

describe("Model Class", function() {
  var geometry;

  beforeAll(function() {
    // Return the promise so Jasmine waits for it
    return loadGeometry()
      .then(function(loadedGeometry) {
        geometry = loadedGeometry;
      })
      .catch(function(error) {
        throw new Error(`Failed to load Geometry: ${error}`);
      });
  });

  it("should access Geometry methods correctly", function() {
    expect(geometry.calculateArea).toBeInstanceOf(Function);
  });
});

Async/Await version (cleaner syntax): #

describe("Model Class", function() {
  var geometry;

  beforeAll(async function() {
    try {
      geometry = await loadGeometry();
    } catch (error) {
      throw new Error(`Geometry loading failed: ${error}`);
    }
  });

  it("should initialize Model with valid Geometry", function() {
    const model = new Model(geometry);
    expect(model.geometry).toBe(geometry);
  });
});

3. For AMD/Require.js Scenarios #

If you’re using AMD modules (like Require.js), use the require callback with done:

describe("Model Class", function() {
  var geometry;

  beforeAll(function(done) {
    require(['path/to/Geometry'], function(GeometryModule) {
      geometry = GeometryModule;
      done();
    });
  });

  // Your test cases here
});

Key Notes: #

• Always handle errors in your async setup—otherwise, if loading fails, your tests will hang or fail silently.
• beforeAll runs once before all tests in the describe block, which is ideal for loading heavy dependencies like Geometry once instead of before each test.
• Ensure your Jasmine version supports the features you’re using (async/await requires Jasmine 2.7 or later).

内容的提问来源于stack exchange，提问作者TomFree