Test-Driven & Fuzz-Driven Development

Write tests that think like attackers. We help teams build security properties into tests and fuzz harnesses so dangerous edge cases get caught before production.

What we cover

  • Security-focused unit tests and invariants

  • Property-based testing strategy

  • Fuzz harness design and coverage goals

  • CI integration for continuous security testing

  • Regression test packs for past issues

  • Test strategy for critical flows and boundaries

Common Failure Modes

Shallow test coverage

Shallow test coverage

  • Happy-path-only tests
  • No adversarial inputs or edge cases
  • Missing state transition coverage
No security properties

No security properties

  • Invariants not encoded anywhere
  • No “must never happen” assertions
  • Weak oracle design for fuzzing
CI and discipline gaps

CI and discipline gaps

  • Tests not enforced in PR gates
  • Flaky tests ignored instead of fixed
  • Security tests run “sometimes”

How we work

01

Pick targets

Pick targets

highest-risk flows and invariants

02

Define properties

Define properties

the behaviors that must always hold

03

Implement harnesses

Implement harnesses

fuzzable and maintainable

04

CI integrate

CI integrate

make it continuous, not occasional

05

Measure

Measure

coverage and bug yield, not vanity metrics

Tools and Standards

Core Tooling

  • Foundry-centric testing workflows for smart contracts
  • Medusa for fuzzing contract behaviors
  • Halmos for symbolic testing where fuzzing struggles
  • SSDF alignment for test discipline and secure delivery

Outputs

  • Test strategy doc + example harnesses
PortswiggerGithubMitreOWASP

What we map to

  • Clear property sets per module
  • Regression prevention as the success criterion
Background

Deliverables

Securing High-Impact Enterprise System

What Our Clients Trust us with

Client Video

We partnered with ImmuneBytes for a security audit of our products. Their expertise and professionalism instilled confidence throughout the process. They promptly addressed our questions, and their thorough analysis significantly enhanced our project's security, safeguarding our users' assets. We highly recommend ImmuneBytes and look forward to future collaborations.

Aruje Jahan

Lokr, Product Owner

ImmuneBytes demonstrated the perfect blend of expertise, commitment, and accountability, resulting in an audit that surpassed expectations. Their thorough approach and dedication ensured a high-quality outcome, reflecting their capability and professionalism in delivering exceptional service.

Dheeraj Borra

Stader Labs, Co-Founder

Robots can do audits, but the personal touch makes a difference. That's why we love Immunebytes! Not only do they do top-class audits, but they also take the time to understand our project and why certain things are done in specific ways. They take the time to ensure we feel heard, which shows in their work.

Yog Shrusti

Farmsent, Co-Founder & CEO

We are thoroughly impressed by their team, who left no scope for a communication gap and provided a quick turnaround time. They took up each requirement with utmost detail and acted on it. It was a pleasing experience to work with you. Looking to working with you guys again!

Mac P

Ethernity, Chief Engineer

What You Need to Know?

Frequently Asked Questions

Fuzz testing is an automated technique that feeds random or semi-random inputs into your code to uncover crashes, edge cases, and unexpected behavior. It is especially effective for parsing logic, state machines, and complex mathematical operations.

Yes—we build fuzzing harnesses that run alongside your existing unit tests. This allows developers to gain fuzzing coverage without disrupting their normal development workflow.

Fuzzers explore unusual input combinations that manual testing often misses, such as extreme values, malformed data, and unexpected state transitions. This helps uncover issues like integer overflows, memory corruption, and logic flaws.

Yes—we develop tailored fuzzing harnesses specific to your codebase. While generic fuzzers are helpful, custom-built fuzzers are far more effective at identifying deep, context-specific vulnerabilities.

Test-driven development encourages developers to define expected behavior and edge cases before writing code. This leads to better error handling, stronger invariants, and early detection of potential security issues.

Continuous fuzzing helps detect regressions and newly introduced bugs over time. It exposes unknown attack vectors early, strengthening the overall robustness of the application.

We configure fuzzing to run on every commit or on scheduled intervals (e.g., nightly). Developers receive alerts when crashes or invariant violations are detected, enabling rapid fixes.

Secure Systems

Let’s Evaluate Risks and Secure your Systems

+917303699708team@immunebytes.com
Immunebytes

A blockchain security audit firm with the goal of making the Web3 space more secure through innovative and effective solutions.

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