4 October 2026 Oussama Belakhdar 3 min read

Testing a blockchain application: smart contracts, transactions and MiCA

On a blockchain, a confirmed transaction cannot be cancelled, and a deployed smart contract cannot be patched like a web application. Testing therefore happens before, and it must cover what a malicious user will try.

Key takeaways

A deployed bug is final: testing happens before deployment, not after.
Test on a testnet or a local network, never with real funds.
Think like an attacker: unauthorised calls, extreme amounts, transaction ordering.
MiCA has applied since 30 December 2024 to crypto-asset service providers in the EU.

Oussama Belakhdar, QA architect and founder of AutomationDataCamp, has worked on software testing projects in this industry. This page sums up what we check first. Our clients are not named.

Industry figures

$2.2 bn Crypto assets stolen in hacks in 2024. Chainalysis — Crypto hacking report 2025

$3.4 bn Crypto assets stolen from January to early December 2025, including $1.5 bn in a single attack (Bybit, February 2025). Chainalysis — Crypto hacking report 2026

Figures published by the organisations cited, not results of our own engagements.

What makes testing hard

The result depends on the chain state, fees and transaction ordering.
Confirmation delays make end-to-end tests slow and flaky unless they are isolated.
The application mixes three layers: the contract, intermediate services and the interface with the user's wallet.

The scenarios we test first

Contract functions: nominal cases, boundary values, overflows, zero amounts.
Access control: a restricted function rejects any unauthorised call.
Events emitted and final state after each transaction.
User journey with a wallet: connection, signature, signature refused, wrong network.
Interface behaviour while waiting for confirmation and on failure.

The framework to know

MiCA, Regulation (EU) 2023/1114. The provisions on asset-referenced tokens and e-money tokens have applied since 30 June 2024; the rest of the regulation, including the authorisation of crypto-asset service providers, since 30 December 2024.

Resilience. Authorised providers also fall within the scope of DORA, with the same resilience testing obligations as other financial entities.

Our method

Start from the risks. We rank features by the impact and likelihood of a defect, then test first what would cost the most.
Automate what comes back in every release. API tests for rules and integrations, Playwright for user journeys, k6 for load, all wired into your CI.
Controlled test data. Fictitious data sets, created for each run, never copied from production.
AI with a review. An assistant speeds up writing scenarios and tests; every generated test is reviewed against our 7-question checklist. See our case study: from a PDF specification to Playwright tests.

Start with an audit

A QA audit reviews your application: a written assessment, a test strategy adapted to your industry and a costed action plan, in 5 days, for €1,000 excl. VAT as a fixed fee. Delivered remotely, in English or French, for companies in the US, the UK, Canada, Australia, Europe, the Gulf and the Nordics. The first scoping session is free.

See the QA audit at €1,000 excl. VAT

Frequently asked questions

Why test a smart contract before deploying it?

Because a deployed contract cannot be changed like a regular application and a confirmed transaction cannot be cancelled. A bug found after deployment can lead to permanent losses.

How do you test a blockchain application safely?

On a local network or a testnet, with fictitious accounts and funds, and automated tests covering the contract, the intermediate services and the interface.

How much does a QA audit cost at AutomationDataCamp?

The QA audit and diagnosis costs €1,000 excl. VAT as a fixed fee, over 5 days: a written assessment, a test strategy and a costed action plan. The first scoping session is free.

Other industries: Healthcare · E-invoicing · Finance · Logistics · E-commerce · Document management. All industries.

Page signed by Oussama Belakhdar, written with the help of AI. Regulatory references link to the official sources above; they are not legal advice.