Jest testing with Resium

CesiumJS
1

There is no Resium category so I’m adding this here, but please let me know if I should post this elsewhere…

Anyone managed to implement jest unit tests for a Resium app?

Here’s what I tried:


import React, { FC } from "react";
import { Viewer } from "resium";
import getWebGLStub from "../getWebGLStub";

interface TestViewerWrapperProps {
	componentToTest: React.ReactNode;
}

const TestViewerWrapper: FC<TestViewerWrapperProps> = (props) => {
	return (
		<div>
			<Viewer
				full
				timeline={false}
				animation={false}
				homeButton={false}
				navigationHelpButton={false}
				baseLayerPicker={false}
				projectionPicker={false}
				skyBox={false}
				sceneModePicker={false}
				skyAtmosphere={false}
				fullscreenButton={false}
				contextOptions={{ getWebGLStub: getWebGLStub }}
			>
				{props.componentToTest}
			</Viewer>
		</div>
	);
};

export default TestViewerWrapper;

import React from "react";
import { render, screen } from "@testing-library/react";
import "@testing-library/jest-dom/extend-expect";
import TestViewerWrapper from "../../testing/TestViewerWrapper/TestViewerWrapper";
import { useCesium } from "resium";

interface WrapperProps {}
function Wrapper(props: WrapperProps) {
	const { viewer } = useCesium();
	return (
		<div>
			{viewer ? (
				<DemoButton
					viewer={viewer}
				></DemoButton>
			) : null}
			;
		</div>
	);
}

describe("<DemoButton />", () => {
	test("it should mount", () => {
		render(<TestViewerWrapper componentToTest={<Wrapper></Wrapper>} />);
		const demoButton = screen.getByTestId("DemoButton");
		expect(demoButton).toBeInTheDocument();
	});
});

I added getWebGLStub.js based on Testing Cesium in Jest - #8 by shane_benlolo, I simply copied the file from the github repo mentioned in the last May 10 post on that link.

This is the error I get:

Jest encountered an unexpected token

Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.

Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.

By default "node_modules" folder is ignored by transformers.

Here's what you can do:
 • If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
 • If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
 • To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
 • If you need a custom transformation specify a "transform" option in your config.
 • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/configuration
For information about custom transformations, see:
https://jestjs.io/docs/code-transformation

Details:

/Users/eli.leblanc/Documents/Repos/cmor-resium-app/node_modules/@cesium/engine/index.js:2
export { default as AutomaticUniforms } from './Source/Renderer/AutomaticUniforms.js';
^^^^^^

SyntaxError: Unexpected token 'export'

> 1 | import { clone, defaultValue, defined, DeveloperError, WebGLConstants } from "@cesium/engine";
    | ^
  2 |
  3 | function getWebGLStub(canvas, options) {
  4 |       const stub = clone(WebGLConstants);

  at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1728:14)
  at Object.<anonymous> (src/testing/getWebGLStub.js:1:1)
  at Object.<anonymous> (src/testing/TestViewerWrapper/TestViewerWrapper.tsx:2:1)
  at Object.<anonymous> (src/components/DemoButton/DemoButton.test.tsx:8:1)
  at TestScheduler.scheduleTests (node_modules/@jest/core/build/TestScheduler.js:333:13)
  at runJest (node_modules/@jest/core/build/runJest.js:404:19)

So clearly there is something wrong with the way I’m trying to use getWebGLStub.js. It is indeed a weird way to do it, but does anyone have suggestions?

1 Like
2

Any update on this? Is the only testing framework compatible with Cesium Karma and Jasmine? Karma is now deprecated and no longer updated with features. It would be nice to know what other alternatives might be available to work with Resium/Cesium.js.

3

Hi @ztatman1 ,
Thanks for your post and welcome to the Cesium community.

There is a more detailed discussion on using Jest to test Cesium in this thread Testing Cesium in Jest - #10 by naftali123 with some additional information
on making use of getWebGLStub.js if you are testing in an environment without access to webGL, such as the command line.

Please let us know if that thread is not helpful and if you do so please include more details and sample code showing your use case.

Thanks,
Luke