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Testing with TypeScript and TS-Jest #519
Description
Hi there,
I was following the TypeScript and Testing guides but I had to work a lot in order to get the tests run with ts-jest.
Setup
This is my setup:
index.ts defines the handler
import { Request, Response, http } from "@google-cloud/functions-framework";
// Register an HTTP function with the Functions Framework
export async function helloHTTPFunction(req: Request, res: Response) {
// Your code here
// Send an HTTP response
res.send("OK");
}
http("helloHTTPFunction", helloHTTPFunction);index.test.ts defines the handler's test
import {
HttpFunction,
Request,
Response,
} from "@google-cloud/functions-framework";
// @ts-ignore
import { getFunction } from "@google-cloud/functions-framework/testing";
describe("HelloTests", () => {
beforeAll(async () => {
// load the module that defines HelloTests
await import("./index");
});
it("is testable", () => {
// get the function using the name it was registered with
const helloHTTPFunction = getFunction(
"helloHTTPFunction"
) as HttpFunction;
// a Request stub with a simple JSON payload
const req = {
body: { foo: "bar" },
} as Request;
// a Response stub that captures the sent response
const res = {
send: (result) => {
// assert the response matches the expected value
expect(result).toBe("OK");
},
} as Response;
// invoke the function
helloHTTPFunction(req, res);
});
});jest.config.ts ts-jest config file
import type { JestConfigWithTsJest } from "ts-jest";
const config: JestConfigWithTsJest = {
preset: "ts-jest",
slowTestThreshold: 5000,
testEnvironment: "node",
silent: true,
modulePathIgnorePatterns: ["<rootDir>/dist/", "/node_modules/"],
testPathIgnorePatterns: [
"<rootDir>/src/fixtures/",
"<rootDir>/dist/",
"/node_modules/",
],
coveragePathIgnorePatterns: [
"<rootDir>/src/fixtures/",
"<rootDir>/dist/",
"/node_modules/",
],
};
export default config;tsconfig.json defines TS settings
{
"compilerOptions": {
"target": "ES2020",
"module": "CommonJS",
"moduleResolution": "nodenext",
"outDir": "dist",
"esModuleInterop": true,
"strict": true,
"skipLibCheck": true
}
}Environment
Node 18.12.1
TypeScript 4.9.5
jest 29.4.3
ts-jest 29.0.5
@google-cloud/functions-framework 3.1.3
OS: macOS Ventura on M1 Pro processor
Error
I get this error when I try to import the testing submodule without the // @ts-ignore in the test file
I think it's related to this TypeScript issue and the way the package.json is declared in @google-cloud/functions-framework module.
The test will also fail if not using the --experimental-vm-modules whith jest, but that's because of the await import("./index") statement in the hook.
So you need to add this to the package.json scripts
"test": "NODE_OPTIONS=--experimental-vm-modules jest"
and then launch npm test.
Workaround
Adding the // @ts-ignore does the trick. However, if I am not messing up with the TS settings too much, wouldn't it be nice to have a more TS-friendly testing module package declaration?
And if you think (and I might agree with you) that this issue is more a TS problem than your library's, then could you please extend the documentation by adding a "testing with typescript" section in the docs (feel free to add my workaround if deemed good enough)?
Activity
cblodgett-sauce commentedon Mar 8, 2023
Goes without saying this is weird because the method exist if you import this way
import functionsFramework from '@google-cloud/functions-framework/build/src/testing';But does not function properly after being ran actively, needs to be reverted and ignored to be useful. I'm sure I'm missing a setting somewhere, but this is ridiculous in the year 2023.
Livshitz commentedon Dec 12, 2023
Something is wrong in the way the types are exported.
As a workaround you should be able to use this instead:
const {getFunction} = require('@google-cloud/functions-framework/testing');