DEV Community: Bristo Biju

How I Generate Unit Tests in 30 Seconds With One ChatGPT Prompt

Bristo Biju — Tue, 26 May 2026 22:38:27 +0000

Writing unit tests is one of those tasks every developer knows they should do more of — and almost nobody enjoys doing.
It's repetitive, it's tedious, and it always feels like the least exciting part of shipping a feature. So I started using AI to do the boring parts for me.
Here's the prompt that generates a complete test suite in under a minute:
The Prompt
Write comprehensive unit tests for this function using [JEST / PYTEST / MOCHA — pick yours].

Cover all of these cases:

Happy path (expected inputs, expected outputs)
Edge cases (empty strings, zero values, max values)
Error conditions (what should throw or return an error)
Boundary values (min/max limits)
Null and undefined inputs

Add descriptive test names so each test reads like documentation.

Function: [PASTE YOUR FUNCTION HERE]
What You Get Back
Running this on a simple input validation function gave me 14 tests covering cases I would have never written manually — including a Unicode character edge case I genuinely hadn't thought about.
The test names alone are worth it. Instead of test('works correctly') you get test('returns false when email is missing @ symbol'). Your test suite becomes documentation.
The Secret Ingredient
The key is asking for named cases explicitly. When you say "write unit tests for this," AI writes 3-4 obvious tests and stops. When you list the specific types of tests you want, it's thorough.
Same principle applies to most AI prompts — specificity is the difference between mediocre and excellent output.
Pair It With This
After generating tests, run this follow-up prompt:
Look at these tests and identify any scenarios that are still missing.
Focus on: concurrency issues, integration points, and security-related inputs.

Tests: [PASTE GENERATED TESTS]
Nine times out of ten it finds at least one thing.
The Bigger Picture
I've built up a collection of 40 prompts like these — for code review, debugging, documentation, system design, DevOps, and AI engineering. If you want them all in one place: [b4m.gumroad.com/l/wehfa]
What's your least favorite part of writing tests? Happy path, mocks, or async testing? Let me know in the comments.

The AI Prompt That Replaced My Senior Engineer Code Reviews

Bristo Biju — Thu, 21 May 2026 22:25:38 +0000

I used to dread code reviews.
Not because of the feedback — because of the wait. You open a PR, ping your team, and sometimes sit idle for hours or days waiting for a review that takes 10 minutes to read.
Then I found a prompt that changed how I work.
The Prompt
Review this code as a senior engineer at a top tech company. Evaluate:

Correctness — does it do what it's supposed to?
Security vulnerabilities — SQL injection, XSS, exposed secrets, improper auth
Performance — bottlenecks, memory leaks, unnecessary loops
Readability — naming, structure, complexity
Test coverage gaps — what's untested?

Prioritize every issue you find as Critical / Medium / Low.

Code: [PASTE YOUR CODE HERE]
Why It Actually Works
Most people prompt AI with "review my code" and get a generic response. The difference here is two things:
Role assignment. Telling the AI it's a senior engineer at a top tech company consistently produces more thorough, production-minded feedback. It stops treating your code like a homework assignment and starts treating it like something that will run in production.
Priority tiers. Without them, AI gives you a wall of feedback with no sense of urgency. Critical/Medium/Low forces it to think about impact — and forces you to act on what actually matters instead of fixing a variable name when there's an auth vulnerability.
Real Example
I ran this on a Node.js API endpoint last week. It caught:

A missing input validation that could cause a crash (Critical)
An N+1 database query I'd completely missed (Medium)
Three variable names that were genuinely confusing (Low)

The whole review took 30 seconds. Not bad.
How To Use It

Copy the prompt above
Replace [PASTE YOUR CODE HERE] with your actual code
Paste into ChatGPT, Claude, or any LLM
Work through the Critical issues first, ignore Low until you have time

One More Thing
This is one of 40 prompts I've collected specifically for developers. If you want the full set — covering debugging, testing, documentation, system design, DevOps, and more — I packaged them into a clean PDF here: [b4m.gumroad.com/l/wehfa]
What do you use AI for most in your dev workflow? Drop it in the comments — always looking for what to cover next.

I Stopped Writing AI Prompts From Scratch. Here Are the 10 I Use Every Day.

Bristo Biju — Tue, 14 Apr 2026 22:37:06 +0000

Every developer I know is using AI now. But most are writing throwaway prompts — vague, inconsistent, and getting mediocre results.
I spent a few weeks refining the prompts I use daily into reusable templates. Here are 10 of the best ones. Just replace the [BRACKETED] parts with your specifics.

The Feature Builder
You are a senior software engineer. Write clean, production-ready [LANGUAGE] code for: [DESCRIPTION]. Include error handling, edge cases, and inline comments. Follow [FRAMEWORK] best practices.
Why it works: Assigning the "senior engineer" role consistently gets more thoughtful, production-quality output.
The Bug Detective
This code produces unexpected behavior: [PASTE CODE]. Expected: [EXPECTED]. Actual: [ACTUAL]. Walk me through your debugging process step by step, identify the root cause, and provide a fix.
Why it works: Forcing step-by-step reasoning catches issues that a direct "fix this" prompt misses.
Deep Code Reviewer
Review this code as a senior engineer at a top tech company: [PASTE CODE]. Evaluate: correctness, security, performance, readability, and test coverage. Prioritize issues as Critical / Medium / Low.
Why it works: The priority tiers mean you act on what matters instead of getting overwhelmed.
Unit Test Generator
Write comprehensive unit tests for this function using [TEST FRAMEWORK]: [PASTE CODE]. Cover: happy path, edge cases, error conditions, boundary values, and null inputs. Add descriptive test names.
Tech to Plain English
Explain this to a non-technical stakeholder: [CONCEPT/CODE]. Use a simple analogy, avoid jargon, and include a real-world business impact statement. Keep it under 150 words.
Why it works: Lifesaver before stakeholder demos.
PR Description Writer
Write a pull request description for: [DESCRIBE CHANGES]. Include: what changed and why, how to test it, breaking changes, and a reviewer checklist.
README Generator
Write a professional README.md for: [PROJECT DESCRIPTION]. Include: title, one-line description, features, tech stack, installation steps, usage examples, and contributing guide.
Prompt Refiner
Improve this AI prompt for better, more consistent results: [ORIGINAL PROMPT]. Rewrite it with clear role assignment, specific output format, constraints, and examples.
Why it works: Meta-prompting. Use AI to make your AI prompts better.
System Design Advisor
Design a scalable system for [USE CASE] handling [SCALE]. Cover: architecture, database choices, caching strategy, API design, and bottlenecks with solutions.
CI/CD Pipeline Builder
Write a [GITHUB ACTIONS/GITLAB CI] pipeline for a [LANGUAGE/FRAMEWORK] app. Include: linting, testing, security scanning, build, and deployment with rollback.

These 10 are from a larger pack of 40 I put together — if you want the full toolkit with all 7 categories, I packaged it as a PDF here: [https://b4m.gumroad.com/l/wehfa, https://payhip.com/b/lN2Aa, https://review-reply-ai.lemonsqueezy.com/checkout/buy/1256ba8e-6b3f-438f-8bf3-54958b30c1cb]
What prompts do you use most? Drop them in the comments — always looking to expand the collection.