ashwanth1109 / jest-generator

Deno script to auto generate jest UT starter for lambda handlers

Jest Generator

Repo consists of:

• Deno script to auto generate jest UT starter
• CDK code to deploy script into S3 bucket

Current Features:

• Currently, only mocks jest dependencies based on imports and sets up describe function

Planned Features:

• Generate a basic template of success-failure tests for lambda
• Deep mocking of dependencies used (if possible)

Instructions for use:

1. Create your deployment env if you want to use your own S3 bucket to store your Deno script object

• Run aws configure
• Add user's ACCESS KEY ID and SECRET KEY to create default profile
• Run cdk bootstrap aws://<account>/<region> in deploy folder if deploying env for the first time
• Run deploy from root (or deploy) folder to deploy your CDK stack

Note: Alternatively, the object url for the script can be shared between multiple people

2. Install deno on your machine

Follow the instructions here

3. Run the deno run command as follows:

Command syntax:

deno run --allow-read --allow-write <s3-url-to-script> <input-file-name> <output-file-name>

Command example:

• deno run --allow-read --allow-write https://jest-generator.s3.ap-south-1.amazonaws.com/index.bundle.js handler.ts handler.spec.ts

4. You can create an alias to run this command without typing the whole thing

In your powershell profile, you can add the following alias

Function SpecGen($readFile, $writeFile) {
    deno run --allow-read --allow-write https://jest-generator.s3.ap-south-1.amazonaws.com/index.bundle.js $readFile $writeFile;
}

Set-Alias spec-gen SpecGen

5. You can now run the command with your alias

Example usage:

spec-gen handler.ts handler.spec.ts

Deploying changes to deno script to S3 bucket

Run build (also cleans up previous dist):

• npm run build

Run deploy:

• npm run deploy

You should now be able to see your new deno script in your S3 bucket

Important Notes:

• Meant to be a starting point for the generated test setup, you will then need to add on top of that
• May generate incorrectly or fail but any output will only be added to end of existing files and not overwrite them
• You can remove the generated code if it doesn't and raise an issue with input and expected output (if possible), and I can work on improving the script