advance

advance is a method on NgtTestBed that allows us to advance frame to run animations in the scene graph.

advance(frames, delta)

advance accepts two arguments:

• frames is the number of frames to advance
• delta is the delta time to use for the animations. It can be a number or an array of numbers.

const { fixture, advance } = NgtTestBed.create(SceneGraph);

await advance(1);
// assert the scene graph state after 1 frame

Example Scenario

For this example, we will use advance to test the animations.

import { NgtTestBed } from 'angular-three/testing';

describe('SceneGraph', () => {
  it('should render', async () => {
    const { scene, fireEvent, advance } = NgtTestBed.create(SceneGraph);
    fireEvent.setAutoDetectChanges(true);

    expect(scene.children.length).toEqual(1);
    const mesh = scene.children[0] as Mesh;
    expect(mesh.isMesh).toEqual(true);

    expect(material.color.getHexString()).toEqual('ffa500');

    await fireEvent(mesh, 'pointerover');
    expect(material.color.getHexString()).toEqual('ff69b4');

    await fireEvent(mesh, 'pointerout');
    expect(material.color.getHexString()).toEqual('ffa500');

    await fireEvent(mesh, 'click');
    expect(mesh.scale.toArray()).toEqual([1.5, 1.5, 1.5]);

    expect(mesh.rotation.x).toEqual(0);
    await advance(1);

    // the cube should have rotated by 0.01 on the X axis since we advanced 1 frame
    expect(mesh.rotation.x).toEqual(0.01);
  });
});