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How to Ensure QA for Smart Contracts in Decentralized Applications

How to Ensure QA for Smart Contracts in Decentralized Applications

Smart contracts are being adopted at an increasing rate. They have the potential to change everything from how we use money to how we vote and even do business transactions. Smart contract platforms like Ethereum allow developers to create applications that can become self-enforcing agreements between two or more parties. This means that once a smart contract is created, it will execute automatically when all of the conditions within the contract are met without any need for human intervention.

The problem with this lack of middlemen is that there isn't anyone around to ask questions if something goes wrong during execution (i.e. bugs in smart contracts). Bugs in smart contracts could range from simple user errors such as forgetting to add Ether before sending tokens to more complicated bugs where the smart contract is doing something completely unintended.

What Is a Smart Contract?

Smart contracts are self-executing contracts in which the terms of the agreement are written into lines of code. Smart contracts live inside a blockchain. They can be activated through transactions initiated by external events or from within the contract itself.

Knowing what smart contracts are is an important part of decentralized applications or dapps, because it helps to eliminate third-party involvement and thus reduce transaction costs associated with contracting parties. Smart contracts are written in programming languages like Solidity or Serpent.


What Are Decentralized Applications?

Decentralized applications, or dapps, are computer programs or digital applications that run on a blockchain or peer-to-peer network of computers. These applications are never centralized and rely on the strength of the blockchain and smart contracts to enforce the parties' agreement.

This feature of these applications is what makes them secure, as it distributes ownership across multiple systems. As a result, anyone who joins this network of applications receives a complete copy of the blockchain. Any change or input introduced by any party, once approved, is also shared by all systems, ensuring everyone is kept up to date with real-time data and assisting in the verification that everything is still in order.

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How to Test a Smart Contract

The first step is to simulate, analyze, and make a close prediction of all possible outcomes in each contract's logic. Here are the questions to be considered when testing Smart Contracts:

  • Which events are to be initiated?
  • Which strategies are to be employed?
  • What is the current state of your contract's balance and status?
  • How and to whom should funds be transferred?
  • What kind of error is this?
  • Who sent the message?
  • What is the current time that is being used?

For example, in a Smart Contract, the user sends Ether to an address not registered on your Smart Contract. In this scenario, there are two possible outcomes, the transaction occurs, and the contract adds a new entry for this account or does nothing if it already exists. This transaction fails because you currently have no code written to handle what happens in this case.

The following are the kinds of tests to do QA on smart contracts:

  • Regression Testing

    Ensures that bugs or errors which are already fixed do not appear again after new code has been added. It can be done by rerunning the Smart Contract with all desired preconditions and post conditions.

  • Unit Testing

    Unit testing, which is used to evaluate a smart contract's individual features, is an automated method that verifies that each Smart Contract function performs appropriately.

  • Compliance Testing

    This is a critical component of smart contract testing since it enables you to ensure that your smart contract complies with all applicable regulatory requirements established by the local government or other governing organizations.

  • Integration Testing

    This type of testing conducts tests on all additional smart contract modules that are connected to other systems and the main application to verify proper integration. This type of test determines the compatibility between Smart Contracts on different networks or nodes and whether they can communicate.


How To Test a Decentralized App

Apart from this, testing any blockchain-based application follows a somewhat similar pattern to testing other applications.

To verify that your application's code is accurate and error-free, your QA engineer is supposed to check every component of it, including the date, contract parties, execution time, hash validation, and payment transfer protocols.

To achieve the above-mentioned results, the following tests are often carried out:

  • End-to-end Testing

    This method of testing is used to check the application's overall quality and to confirm that all dApp components function as intended. End-to-end checks, on the other hand, attempt to predict the behavior of a real user and how he or she would interact with the system.

  • Integration Testing

    QA engineers will examine the interaction of modules and systems as a whole, as well as the integration of data from the front-end to the back-end.

  • Smart contracts testing and transaction testing

    This type of testing includes checking the number of operations performed, service fields, hash validity, transaction time, author and recipient data, and many other things.


Key Advantages of Smart Contracts Over Traditional Contracts

Testing smart contracts are important because of their uniqueness. Smart contracts are making business operations more effective and efficient than ever before, thus they need to be tested rigorously to avoid any unforeseen bugs or defects.

Smart contracts have a number of advantages over traditional contracts, including the following:

  • Intermediaries, Automation, and Time Saving

    • When a condition is met, the contract is immediately executed.
    • Due to the fact that smart contracts are digital and automated, there is no documentation to manage.
    • There is no time wasted fixing errors that can arise while manually filling out documents.
  • Accuracy and Transparency

    • There is no need to be concerned about information being altered for personal advantage, as no third party is involved.
    • Participants exchange encrypted transaction logs.
  • Security

    • Blockchain transaction records are extremely difficult to hack because they are encrypted.
    • Additionally, because each item on a distributed ledger is connected to the entries before and after it, hackers would need to alter the entire chain to change a single record.
  • Cost

    • Smart contracts eliminate the need for middlemen and the associated time delays and expenses.

Smart Contract Use Cases

Smart contracts have a wide range of applications. They can be used for simple economic transactions like money transfers or for smart access management in the sharing economy. A wide range of sectors have use cases for blockchain technology. Below are the industries where smart contracts can be used:

  • Digital Identity: Smart contracts can hold information about an individual's identity, allowing people to control their digital identities.
  • Real Estate: Smart contracts can be used to conduct the sale of a property without going through an agency. Smart contract records ensure that all formalities are completed before transactions can take place and avoid any future conflicts or disagreements over whether documents have been faxed or emailed.
  • Smart contracts and flight insurance: It can be used to receive insurance payouts after a flight has been delayed. Smart contracts are ideal for this use case because they have the ability to detect delays on their own, which allows them to trigger automatic compensation payments without any input from an off-chain source.
  • Blockchain implementation of smart contracts in voting: This can be used to record voter preferences and conduct a secure election. Voters would be able to cast their votes securely without worrying about tampering.
  • Government: Smart Contracts can be used to digitize the process of submitting and storing government documents.
  • Automobile: Smart Contracts can be used in car rental and ride-sharing. Smart Contracts would allow for a seamless process when going from renting to sharing, which prevents the hassle of having to return a vehicle before renting another one.
  • Supply Chain: In supply chain management, Smart Contracts can be used to track the movement of goods, ensuring that everything is delivered on time and with all necessary documentation.
  • Insurance: Smart Contracts can be used to automate insurance payouts. Smart Contract technology can detect when a triggering event occurs and automatically make an automatic payment without requiring input from a human being, which means no delays in processing claims.


Blockchain technology has the potential to revolutionize how we create and share data, opening up a whole new world of possibilities for IT professionals. This is an exciting time in history that will require us to adopt new ways of thinking about our workflows. In order for this next generation of software development to succeed, it's crucial that there are quality assurance processes in place from day one.

At QASource, we understand that you don't want to be left behind when it comes to this new technology and that you require a partner who knows what blockchain means for businesses today and in the future. You can rest easy knowing that our experts will find any issues before they become problems for your users or customers.

When it comes to building trust with clients and customers alike, especially with new technology like blockchain, having a reliable partner is crucial. QASource will give you access to our expertise and knowledge on how best to implement this technology into your business model without sacrificing security or stability. Smart Contracts are just the beginning. Get in touch with us today!!


This publication is for informational purposes only and nothing contained in it should be considered legal advice. We expressly disclaim any warranty or responsibility for damages arising out of this information and encourage you to consult with legal counsel regarding your specific needs. We do not undertake any duty to update previously posted materials.