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    How to Test Blockchain Applications – A Complete Guide

    In this blog, we shall discuss how to test blockchain applications and the various methods and interfaces for testing blockchain applications.

    Cryptocurrencies like Bitcoins and altcoins have been in the news and are a frequent topic of discussion on the internet ever since it was introduced in 2009. All the major cryptocurrencies are experiencing major growth in the last two years. In fact, in 2017, the price of bitcoins grew from $750 per token in January to $5856 towards the end of the year. This glorious price hike got a lot of people talking and the initial investors were rolling around in good money.

    The attention that cryptocurrencies get leads people to ponder over the technology behind the bitcoins and other cryptocurrencies – blockchain technology.

    Blockchain technology is widely adopted in many industries today. A few of the businesses that have embraced blockchain technology for good are supply chain management, retail and logistics, notary, digital identification, and healthcare record-keeping systems. Considering the wide-scale application of blockchain technology and how much more it will be popular in the future, we should know how important testing blockchain applications is.

    So, if you are a blockchain application tester, it’s about time you think about what effect would this new technology have on your day-to-day work, what new opportunities will it create, and about current skill set. What new tools and skills will you need to learn to test blockchain applications?

    In this blog, we shall briefly go through what blockchain technology is and how can testers prepare for testing blockchain applications.

    What Is Blockchain?

    Blockchain concept, What is Blockchain?
    Blockchain concept, What is Blockchain?

    The blockchain is a decentralized digital record that is based on peer-to-peer data sharing. It is a digital record that can be used to store anything of value. Each element in a blockchain is called a block. New blocks with new records are constantly added to the block. These blocks are immutable and there is just no way in which you can remove a block once it has been added to the blockchain. The validation of the data stored in the blockchain is done by mutual consensus. Hence, the technology is very transparent.

    Another strong foothold of blockchain technology is that it is highly secure and there is no way the data can be corrupted. If a hacker intends to break into a blockchain network, he has to get into every computer that is a part of the node at the same time. This is a near-impossible feat.

    For updating the computers in the blockchain network, the machines have to be in sync. Although all machines will have the same data, only the latest transactions are synced more often.

    What Is It Used For?

    Today, the blockchain is used mainly for the financial business and automobile industries because of its highly secure technology. It is the technology that powers cryptocurrencies like Bitcoin and Ethereum.

    Now, recently there have been concerns regarding data privacy in public blockchains. this has given rise to Private blockchains where the entry of members to the blockchains is governed by the existing members. Have a glimpse over the major difference between Public Blockchain vs private Blockchain.

    Tests and Techniques for Blockchain Applications

    There are a lot of tests that should be performed at the various stages of developing blockchain application projects. A few types of tests are described down below and this ensures a high level of test coverage and quality for blockchain applications

    #1. Unit Tests

    A Unit test helps the developers in ensuring that their code is functioning perfectly at the lowest levels and smallest parts of functionality. This is always the first point of defense to ensure that an application identifies the majority of bugs at an early point during development.

    #2. Integration Tests

    Integration tests help the developers and testers to ensure that the communication of their code between different components is perfect and the communication is right between internal and external systems like databases.

    #3. User Interface

    User interface (UI) testing sees how the blockchain application works from the user’s perspective. It’s very important to ensure this. You should do UI testing to make sure the user’s experience is positive. If they find any issues, get feedback on where the application doesn’t perform well.

    #4. Application Programming Interface

    Application programming interface (API) testing ensures that the tester has validated the responses that your application receives from external APIs. it also makes sure of the fact that the formats of your API requests are correct and are being handled correctly.

    With blockchain applications, there is a type of technology that is similar to APIs. It is called Smart contracts and allows you to adopt the same testing practices for APIs.

    So, what Are Smart Contracts?

    Smart contracts play a major role in the validation technology in a blockchain application. A smart contract is a self-executing contract. The rules and regulations of a smart contract are coded into a blockchain. The system enforces the terms of the contract once the conditions are met.

    The smart contract ensures that there is no need for third parties to ensure the successful execution of the terms and conditions of the contracts.

    A smart contract is very similar to an API in functioning, as it has public functions that can be used by anyone registered on that particular blockchain network. However, it cannot call external web APIs.

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    So what role does a tester play in this case?

    Well, once a smart contract is coded into a blockchain, it cannot be altered. So, the testing should be done very accurately and the tester should ensure that everything important and necessary has been covered.

    If there is any defect in the smart contract, then we will need to create a new version of the contract and adopt it. We cannot get to transfer data from an old contract to its new version. The developer has to manually initialize the old data to the new contract.

    It is also not viable to update a contract and roll back on the update. Doing this will increase the complexity of development. Moreover, implementing and running the unit and integration tests mentioned above on your blockchain application before it reaches the production stage can save major time and money in rectifying defects.

    What Skills Do Testers have for testing Blockchain Applications?

    Although blockchain applications are a relatively new entity, testers do not require any special skills to test them. We have developed certain skills that testers should have for testing blockchain applications. Some of them are natural skills of good testers or simply skills that one needs to learn early on in their testing career.

    • Critical Thinking

    The ability to analyze critically and think about and around a problem is a very precious skill that testers must have and will be even more in demand for testing blockchain applications.

    Testers are constantly in dilemma about problems such as Will transactions still hold true and execute themselves if x, y, and z are not done? What happens if the network has lots of transactions waiting for confirmation? What feedback should be given to the user in these cases? Should this be the feedback given to the user? Or is this feedback exposing any security risks?

    Another thing to consider when a tester embarks on a new project is to question whether blockchain is the best technology for that particular use. It’s a very new technology, so everyone will want to use it out of the sake of curiosity, but it may not be suitable for the results you want to get. The tester should also look at things like compliance issues.

    • Test Design Techniques

    A good tester should know the basics of test design techniques, like boundary value analysis and equivalence partitioning. This will make sure that you are equipped to constantly quip about and check the inputs and outputs of the blockchain application.

    The tester should always question how the application will act when you input values that are within, on the edge, and outside of the boundaries of acceptable values. Can the blockchain application complete the transaction? If it cannot be completed, what type of error will be returned? Is this error code correct for the type of error returned? Should it return anything at all?

    • Automation

    Strong automation skills in all languages, both for the lower-level unit, mid-level integration, or API or high-level UI tests, are good skills that the testers must possess to test blockchain applications. When the testers have a strong foothold on automated tests, they will ensure that the majority of issues are found early in development.

    • UI Testing in manual mode

    If we have a good set of automated tests, testers can then channel their focus on the other issues that need to be found out through exploratory testing performed in manual mode.
    The tester should be able to work independently, investigate different areas of the blockchain application, find the weak areas, and able to successfully reproduce these in a frequent manner. Despite the world looking for automation to perform most of the repetitive and boring tasks, manual testing skills are still something that the testers should improve.

    • Ability to learn new tools quickly

    As blockchain technology becomes increasingly popular, the tools for testing blockchain application technology will also grow and improve in its abilities. A good tester should be able to learn to use these new testing tools quickly and judge which is the best one for the blockchain application you are testing.


    A good tester should be prepared for the future and prepare for testing blockchain application development. From this blog, you will have a better understanding of blockchain technology and will find it easy to test blockchain applications.
    Push further into the blockchain application testing arena and try to improve in the areas where you are the weakest so that you have the best chance to grow your skills when testing blockchain applications.

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    Ecbert Malcom
    Ecbert Malcom
    I am a resident author at Broodle.

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    cyril Morris

    Nice blog. We are also working in blockchain development. Definitely, it will help us. Thanks For sharing