Add an example of unit testing with Jest (pulumi#1233)

* Add an example of unit testing with Jest
* Update testing-unit-ts-mocks-jest/README.md
* Un-export the untested

Co-authored-by: Laura Santamaria <[email protected]>

testing-unit-ts-mocks-jest/.gitignore

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+/bin/
+/node_modules/

testing-unit-ts-mocks-jest/Pulumi.yaml

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+name: testing-unit-ts-mocks-jest
+runtime: nodejs
+description: An example of using Jest with Pulumi to write test-driven code that mocks AWS infrastructure.
+template:
+ config:
+ aws:region:
+ description: The AWS region to deploy into
+ default: us-east-2

testing-unit-ts-mocks-jest/README.md

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+# Unit Testing AWS Infrastructure with Jest
+
+An example of using [Pulumi](https://pulumi.com/) with [Jest](https://jestjs.io/), the JavaScript testing framework, to write in-memory unit tests that mock AWS infrastructure. The program under test deploys a single [AWS Lambda function](https://aws.amazon.com/lambda/) and an associated [Lambda Function URL](https://docs.aws.amazon.com/lambda/latest/dg/lambda-urls.html).
+
+[![Deploy with Pulumi](https://get.pulumi.com/new/button.svg)](https://app.pulumi.com/new?template=https://github.com/pulumi/examples/tree/master/testing-unit-ts-mocks-jest)
+
+## Prerequisites
+
+1. [Install Pulumi](https://www.pulumi.com/docs/get-started/install/).
+1. [Install Node.js](https://www.pulumi.com/docs/intro/languages/javascript/).
+1. Configure your [AWS credentials](https://www.pulumi.com/docs/intro/cloud-providers/aws/setup/).
+
+### Deploying the App
+
+1. Clone this repo, change to this directory, then create a new [stack](https://www.pulumi.com/docs/intro/concepts/stack/) for the project:
+
+ ```bash
+ pulumi stack init
+ ```
+
+1. Specify an AWS region to deploy into:
+
+ ```bash
+ pulumi config set aws:region us-west-2
+ ```
+
+1. Install Node dependencies and run the tests:
+
+ ```bash
+ npm install
+ npm test
+ ```
+
+ In a few moments, the tests should pass.
+
+1. If you'd like to deploy the program as well, run `pulumi up`. In a few moments, the `FunctionUrl` of the `timeURL` Lambda will be emitted as a Pulumi [stack output](https://www.pulumi.com/docs/intro/concepts/stack/#outputs) called `audioURL`:
+
+ ```bash
+ ...
+ Outputs:
+ audioURL: "https://o3vbc73qd2vxrhtaao5v53yeaa0sricr.lambda-url.us-west-2.on.aws/"
+ ```
+
+1. When you're ready, destroy your stack and remove it:
+
+ ```bash
+ pulumi destroy --yes
+ pulumi stack rm --yes
+ ```

testing-unit-ts-mocks-jest/index.spec.ts

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+// Copyright 2016-2022, Pulumi Corporation. All rights reserved.
+
+import * as pulumi from "@pulumi/pulumi";
+import "jest";
+
+function promiseOf<T>(output: pulumi.Output<T>): Promise<T> {
+ return new Promise(resolve => output.apply(resolve));
+}
+
+describe("My speaking clock", () => {
+
+ // Define the infra variable as a type whose shape matches the that of the
+ // to-be-defined resources module.
+ // https://www.typescriptlang.org/docs/handbook/2/typeof-types.html
+ let infra: typeof import("./resources");
+
+ beforeAll(() => {
+
+ // Put Pulumi in unit-test mode, mocking all calls to cloud-provider APIs.
+ pulumi.runtime.setMocks({
+
+ // Mock calls to create new resources and return a canned response.
+ newResource: (args: pulumi.runtime.MockResourceArgs): {id: string, state: any} => {
+
+ // Here, we're returning a same-shaped object for all resource types.
+ // We could, however, use the arguments passed into this function to
+ // customize the mocked-out properties of a particular resource.
+ // See the unit-testing docs for details:
+ // https://www.pulumi.com/docs/guides/testing/unit
+ return {
+ id: `${args.name}-id`,
+ state: args.inputs,
+ };
+ },
+
+ // Mock function calls and return whatever input properties were provided.
+ call: (args: pulumi.runtime.MockCallArgs) => {
+ return args.inputs;
+ },
+ });
+ });
+
+ beforeEach(async () => {
+
+ // Dynamically import the resources module.
+ infra = await import("./resources");
+ });
+
+ describe("function URL", () => {
+
+ it("is publicly accessible", async () => {
+ const authType = await promiseOf(infra.timeURL.authorizationType);
+ expect(authType).toBe("NONE");
+ });
+
+ it("is CORS-friendly", async () => {
+ const authType = await promiseOf(infra.timeURL.cors);
+ expect(authType).toEqual({
+ allowOrigins: ["*"],
+ allowMethods: ["GET"],
+ });
+ });
+
+ it("is bound to the right Lambda function", async () => {
+ const timeFuncName = await promiseOf(infra.timeFunction.name);
+ const timeURLFunc = await promiseOf(infra.timeURL.functionName);
+ expect(timeFuncName).toEqual(timeURLFunc);
+ });
+ });
+});

testing-unit-ts-mocks-jest/index.ts

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+// Copyright 2016-2022, Pulumi Corporation. All rights reserved.
+
+import "./resources";
+
+export { audioURL } from "./resources";

testing-unit-ts-mocks-jest/jest.config.ts

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+// Copyright 2016-2022, Pulumi Corporation. All rights reserved.
+
+import type { Config } from "@jest/types";
+
+const config: Config.InitialOptions = {
+ preset: "ts-jest",
+};
+
+export default config;

testing-unit-ts-mocks-jest/package.json

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+{
+ "name": "testing-unit-ts-mocks-jest",
+ "devDependencies": {
+ "@types/jest": "^28.1.1",
+ "@types/node": "^14",
+ "ts-jest": "^28.0.5"
+ },
+ "dependencies": {
+ "@pulumi/aws": "^5.0.0",
+ "@pulumi/awsx": "^0.40.0",
+ "@pulumi/pulumi": "^3.0.0",
+ "node-fetch": "^2.6.7"
+ },
+ "scripts": {
+ "test": "jest"
+ }
+}

testing-unit-ts-mocks-jest/resources.ts

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+// Copyright 2016-2022, Pulumi Corporation. All rights reserved.
+
+import * as pulumi from "@pulumi/pulumi";
+import * as aws from "@pulumi/aws";
+
+const fetch = require("node-fetch");
+
+// Convert the current time into a speech-friendly string.
+function getSpeechText() {
+ const now = new Date();
+ now.setSeconds(now.getSeconds() + 6);
+
+ const local = new Date(now.toLocaleString("en-US", { timeZone: "America/Los_Angeles" }));
+ const localHour = local.getHours();
+ const localMinute = local.getMinutes();
+ const h = localHour > 12 ? localHour - 12 : localHour;
+ const m = localMinute < 10 ? `oh ${localMinute}` : localMinute; // So 2:03 -> "two-oh-three"
+ const s = local.getSeconds();
+
+ return `At the tone, the time will be ${h} ${m}. And ${s} seconds.`;
+}
+
+export const timeFunction = new aws.lambda.CallbackFunction("time-function", {
+
+ // Update the Lambda callback body to convert the current time into an MP3 file.
+ callback: async () => {
+ const text = getSpeechText();
+ const speechURL = `https://translate.google.com/translate_tts?ie=UTF-8&q=${encodeURIComponent(text)}&textLen=${text.length}&tl=en&client=tw-ob`;
+ const beepURL = "https://www.pulumi.com/uploads/beep.mp3";
+ const ttsResponse = await fetch(speechURL);
+ const beepResponse = await fetch(beepURL);
+ const speech = await ttsResponse.arrayBuffer();
+ const beep = await beepResponse.arrayBuffer();
+
+ // Tack a beep onto the end of the audio returned from Google Translate, then
+ // render the whole thing as a base-64 encoded string.
+ const body = Buffer.concat([Buffer.from(speech), Buffer.from(beep)]).toString("base64");
+
+ // Return an appropriately shaped HTTP response.
+ return {
+ body,
+ headers: { "Content-Type": "audio/mpeg" },
+ isBase64Encoded: true,
+ statusCode: 200,
+ };
+ },
+});
+
+export const timeURL = new aws.lambda.FunctionUrl("time-url", {
+ functionName: timeFunction.name,
+ authorizationType: "NONE",
+ cors: {
+ allowOrigins: ["*"],
+ allowMethods: ["GET"],
+ },
+});
+
+// Export the public URL of our shiny new service.
+export const audioURL = timeURL.functionUrl;

testing-unit-ts-mocks-jest/tsconfig.json

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+{
+ "compilerOptions": {
+ "strict": true,
+ "outDir": "bin",
+ "target": "es2016",
+ "module": "commonjs",
+ "moduleResolution": "node",
+ "sourceMap": true,
+ "experimentalDecorators": true,
+ "pretty": true,
+ "noFallthroughCasesInSwitch": true,
+ "noImplicitReturns": true,
+ "forceConsistentCasingInFileNames": true
+ },
+ "files": [
+ "index.ts"
+ ]
+}