Blockchain App Testing: Strategies and Nuances

The first blockchain platform was launched with the introduction of bitcoin in 2008. How do we approach Blockchain App testing? While many still associate this technology with cryptocurrencies, enterprises have recently started to use it for other purposes that require a secure storage of huge amounts of data. This growing interest in blockchain can be linked to the rapidly increasing affordability of data storage and computational power.

Nowadays, companies that operate in logistics, healthcare, real estate, and other industries are experimenting with blockchains to improve traceability, transparency, and security, and decrease operational costs. Consequentially, while becoming more mainstream, new challenges related to this technology’s security have emerged.

At its finest form, blockchain is far more secure than any other record-keeping system. Every new transaction is encrypted, linked to the previous one, and can’t ever disappear, making blockchain immutable and hard to hack.

However, it is still a code, and any code can be flawed. When it comes to blockchain, the negative consequences of vulnerabilities can be much more significant than for other record-keeping systems. For example, many of today’s blockchain applications are centered on smart contracts, which automatically perform a certain action when predetermined conditions described in a contract are met. In this case, the code becomes the contract.


Now think about the consequences of an improperly conducted contract, which executes itself and can’t be altered. What if a health-supporting device makes the wrong adjustments to its parameters and affects the patient’s condition? Even in its most basic form, improperly coded blockchain platforms introduce massively-scaled risks, as the wrongdoers can compromise all blockchain nodes at once by inserting data into the chain with malicious intent.

This is why software testing becomes increasingly relevant in the blockchain realm. Quality assurance engineers from a1qa share their selection of blockchain app testing nuances, including those common to certain testing types.


Live Environment vs. Test Networks

Testing blockchain in a live environment is simply not cost-efficient compared to a testnet. Every transaction executed on a live blockchain has to be processed by miners, who charge certain fees for this work. Testnets, on the other hand, offer fee-free transaction processing, which makes them a more attractive choice for blockchain app testing.

Companies can use public networks like Ropsten or Kovan, which are specifically built for testing Ethereum-based applications. The choice of a public testnet depends on the blockchain use case. For example, Kovan doesn’t provide Ether mining possibility but is immune to spam attacks. On the contrary, Ropsten’s vulnerability to spam is compensated by Ether mining support.

As you can see, the cost of a cheap testing environment comes at the expense of its flexibility. For example, by relying on a public blockchain testnet, QA engineers can’t have control over the frequency or latency of the testing environment.


Unit Testing

Unit testing is the most basic prerequisite for production-ready blockchain solutions. However, it’s important to keep in mind that not all contract languages enable unit testing capabilities by default according to Vanderbilt University researchers. At the same time, the most popular blockchain platforms including Ethereum and Hyperledger Fabric provide unit testing functionality.


Integration Testing

Given that blockchain is often deployed across many different systems and their components need to communicate with each other in real time, integration testing is essential to ensure that interaction between them works as expected.

For example, when testing cryptocurrency blockchain projects, it’s critical to ensure that the API receives and sends correct data. The same goes for the integration of enterprise resource planning and customer relationship management systems, if that’s the case.

Integration testing becomes even more significant when blockchain is coupled with IoT devices as runtime characteristics have to be verified, and both software and hardware compatibility have to be checked.


Functional Testing

 There is a list of things to take into account regarding the functional testing of blockchains:

Block size. Considering that the block size is limited to 1MB, it’s critical to test the system’s behavior when data going into the block exceeds the threshold.

Encryption and decryption. Given the peer-to-peer nature of blockchain applications, one has to verify that no data is lost during transfer. For example, when testing blockchain wallets, you have to ensure that both sending and receiving wallets’ transaction amounts are consistent.

Block addition. Every new block attached to a blockchain can’t get altered or changed, which significantly increases the importance of block addition testing. Moreover, it’s crucial to consider how the system responds to block addition performance-wise, as blockchain has to spend extra resources on network changes.

Smart contracts. Once deployed, smart contracts can’t be controlled by any party or an intermediary. This is why it’s vital to ensure that smart contract interfaces with the blockchain and data correctly and consistently, and the business logic is validated across various scenarios. This also makes test automation essential, as manually testing different combinations of many inputs in the blockchain environment is inefficient. Unfortunately, simulating every possible scenario is costly, as some testing cases like Byzantine Fault Tolerance (BFT) algorithm validation demand enormous processing powers and hundreds of machines working at once.

Performance Testing

QA specialists need to ensure that blockchain performance is stable and responsive when dealing with a high number of transactions, multiple node updates, and consensus failures. Additionally, it’s important to consider that even with the same number of transactions, performance can still vary depending on the data type or server locations. Essentially, this testing type is critical to assessing the scalability of a blockchain.


Testing is a critical aspect of blockchain app development. While flawless blockchain systems are superior to any other record-keeping solutions, poorly-tested ones amplify the negative effect of any incidents. Given that blockchain apps significantly differ from other software solutions, assessing all the risks and different performance scenarios is only possible with a deep understanding of the technology.

Check out all the software testing webinars and eBooks here on

About the Author


At a1qa, Alexander Golubovich is a Unit Coordinator having 11+ years of in-depth experience in QA. Alexander is a professional at providing effective QA solutions and coaching passionate QA specialists. With over 100 successfully completed projects across such industries as eHealth, real estate, eCommerce, media and entertainment, and many more, he manages a 140+ QA team helping the global customers from Fortune 500 list enhance the software quality of delivered solutions, thus, boosting customer experience and accelerating time to market.
Find out more about @a-golubovich

Related Content