Smart contracts are written in the high-level, contract-oriented language known as Solidity. It was created by the Ethereum Blockchain Platform’s core developers. Solidity is used for writing and deploying smart contracts on the Ethereum Virtual Machine and other blockchain development platforms.
Developers can create apps that need self-enforcing business logic to be incorporated into smart contracts by using Solidity. Of course, it is not just about creating smart contracts but also testing them so that a company’s project is successful.
In this article, we will go into detail about the different types of smart contract testing, how Solidity works, and why testing smart contracts with Solidity is essential.
What is Solidity?
The introduction of Bitcoin more than ten years ago sparked a fresh wave of innovation in the programming world. Some early adopters of cryptocurrencies recognized the promise of decentralized systems and consensus, and they began experimenting with concepts of applying the Bitcoin protocol’s fundamental principles to various applications.
As an early proponent of Bitcoin, Vitalik Buterin first suggested developing a different protocol to support more complex smart contracts than those supported by the Bitcoin network. Bitcoin was designed primarily to function as sound money, so its structure is straightforward—and for a good reason. Buterin proposed the concept of Ethereum, a complicated system of interconnected smart contracts, to carry out more complicated transactions without an intermediary to validate them.
With Ethereum, the concept of a transaction was expanded to include a wide range of other agreements that could be carried out through a highly flexible and programmable protocol. In other words, Ethereum increased the range of options, encouraged innovation, and added a certain amount of human-style problem-solving to the equation. But, of course, to accomplish its new goals, this new blockchain protocol has to be Turing-complete (or as close to Turing completeness as possible).
Understanding the relationship between Solidity and Ethereum
Before we dive into any further details about Solidity, it’s critical to examine the foundations of this programming language and the Solidity smart contracts that make up Ethereum’s transactional architecture.
Both Solidity and Ethereum are unique concepts built atop brilliant notions. It all began with research into the nature of calculation and computation and the desire to build machines with computing power close to that of humans.
Ethereum was created as a result of years of hard work by eminent mathematicians, computer scientists, and cryptographers. Additionally, it incorporates a variety of ideas, including decentralization, immutability, states, networks, game theory, and more. Back-reading on finite state machines is also crucial.
Ethereum & Solidity Smart Contracts
In order to understand how Ethereum works, companies must first be familiar with the technology that Bitcoin runs on. This includes a fundamental understanding of the operation of distributed ledgers, mining, node operation, and the purpose of the blockchain.
Bitcoin sparked the blockchain revolution, but Ethereum took the fundamental blockchain idea and ran with it. Ethereum goes beyond distributed ledger data validation and storage. With the help of Ethereum, a wide range of transactions and advanced operations can be conducted over a complete network utilizing a variety of coins or tokens, including Bitcoin. This network makes sure that the code is executed consistently and that the outcomes are documented and verified by consensus.
The software used to power Ethereum is free and open-source and utilizes a decentralized computer network. Joining this network is optional. The network supports the Ethereum blockchain. This network also ensures that smart contracts are executed using the nodes or computers of voluntary participants.
The Ethereum Virtual Machine or EVM
Every Ethereum node, or fully participating node in the network, contains an embedded virtual stack called the EVM that runs contract bytecode. Since the EVM is a Turing complete system, it can carry out any logical operation related to computational operations.
The EVM is one of the fundamental elements of the Ethereum protocol, enabling consensus. By executing smart contracts, whose results are entirely deterministic or guaranteed, a consensus is attained in the protocol. It is also essential to Ethereum’s economic structure. For example, Ethereum charges costs for carrying out software instructions, whereas Bitcoin compensates users for completing transactions. With Ethereum’s gas mechanism, users can use Ether, the platform’s native currency, to pre-pay for the instructions they want to run on the EVM.
What Solidity Does For Ethereum
Instructions from Solidity smart contracts are translated into bytecode for the EVM. As previously established, the EVM instances that run on the Ethereum network’s nodes enable them to concur on the execution of a certain set of instructions.
Now that we know about Solidity, let us look into what smart contract testing is. We’ll also talk about the different types of smart contract testing, and why it is important for blockchain companies.
What is Smart Contract Testing?
The term “smart contract testing” refers to the process of carefully examining and evaluating a smart contract to determine the level of its source code during the development cycle. As a result, testing a smart contract minimizes the likelihood of software faults that could result in expensive exploits and makes it easier to find flaws and vulnerabilities.
Automated vs. Manual Testing
Testing of smart contracts can take many different approaches, with many techniques having advantages. Automated testing and manual testing are the two main types of testing methods for Ethereum smart contracts. Automated testing is the process of scripted testing of smart contracts using automated technologies. This method makes use of automated software that can run numerous tests to identify smart contracts’ flaws.
Compared to manual analysis, automated testing is more productive, requires fewer resources, and guarantees greater levels of coverage. In addition, to compare expected behaviors with actual outcomes, automated testing techniques can also be set up with test data.
Manual testing is human-assisted and requires someone to carry out the testing procedures by hand. A type of manual testing for smart contracts is code audits, in which developers and auditors examine each line of the contract code. Smart contract manual testing demands a high level of competence as well as a significant time, money, and effort commitment. Additionally, manual testing is occasionally vulnerable to issues with human error. Applying manual testing to smart contracts, however, has certain advantages. For example, code audits use human intelligence to identify contract code flaws that automated testing could miss.
Components of Automated Testing
1) Functional Testing
Functional testing ensures that each function in the code operates as intended and checks the functioning of a smart contract. Understanding how a company’s smart contract should perform in specific circumstances is necessary for functional testing. Then, the company can test each function by carrying out calculations with a set of data and comparing the results to what was anticipated.
Unit testing, integration testing, and system testing are the three techniques that make up functional testing.
A smart contract’s separate components are tested for accuracy as part of unit testing. A unit test is easy to perform, quick and explains what went wrong if it fails.
Unit tests are essential for creating smart contracts, especially when new logic needs to be added to the code. They can validate that each function behaves as planned by observing its behavior.
Often, assertions, quick, informal statements defining the specifications for a smart contract, must be written to run a unit test. Then, each assertion can be tested using unit testing to verify if it holds true when put to use.
On the testing hierarchy, integration testing is above unit testing. This is because the smart contract’s constituent parts are tested in conjunction during integration testing.
This method of testing finds mistakes resulting from interactions between various contract elements or contracts. If a company has a sophisticated contract with numerous functions or one that interacts with other contracts, it should use this method.
Integration testing can help ensure the effectiveness of inheritance and dependency injection concepts.
The last stage of functional testing for smart contracts is system testing. To determine whether the smart contract meets the technical requirements, a system examines it as a single, fully integrated product.
Businesses can think of this phase as testing the smart contract’s end-to-end flow from the perspective of the user. It requires the deployment of a smart contract on a network that simulates production, such as a testnet or development network. This is a useful approach to undertaking system testing.
Here, end users can test the contract’s functionality and report any business logic or general operation problems. System testing is crucial because code changes cannot be made once the contract is implemented in the primary EVM environment.
2) Static/Dynamic Analysis
There are two automated testing techniques for assessing the security properties of smart contracts: static analysis and dynamic analysis. However, each method takes a different approach to identifying contract code flaws.
Before execution, a smart contract’s source code or bytecode is examined using static analysis. As a result, businesses can troubleshoot contract code without actually executing it. Static analyzers can help comply with best practices and find common vulnerabilities in Ethereum smart contracts.
To find bugs in a company’s code, dynamic analysis methodologies demand running the smart contract in a runtime environment. Dynamic code analyzers track how contracts behave as they are being executed and produce a thorough report of any vulnerabilities or property violations.
Contract testing methods that use dynamic analysis include fuzzing. Fuzz testing involves feeding a company’s smart contract with corrupted and false data and watching to see how the contract responds.
Like any software, the operation of smart contracts depends on the inputs given by users. Furthermore, even while we presume users would supply accurate inputs, this may not always be the case.
In some circumstances, submitting erroneous input values to a smart contract may result in resource leaks, crashes, or, even worse, unexpected code execution. Fuzzing initiatives help businesses avoid such issues by identifying them earlier.
Components of Manual Testing
1) Code Audits
A code audit analyzes a smart contract’s source code to find any potential weak points, security holes, or improper development techniques. Although code audits can be automated, we are talking about human-assisted code analysis in this case.
Code audits must adopt an attacker perspective to identify potential attack vectors in smart contracts. Therefore, analyzing every line of source code is a basic need for creating secure smart contracts, even if businesses undertake automated audits.
To provide consumers with more confidence in the security of smart contracts, they can also hire a security audit. Audits draw from in-depth research conducted by cybersecurity experts and identify potential flaws or defects that could impair the performance of smart contracts.
2) Bug Bounty
A bug bounty is a monetary award provided to a person who identifies a vulnerability or flaw in the source code of a program and informs the creators. Since bug bounties entail requesting people to assist in identifying flaws in smart contracts, they are comparable to audits. The main distinction is that bug bounty schemes accept participants from the whole developer/hacker community.
Bug bounty schemes frequently draw a diverse group of independent security experts and ethical hackers with specialized knowledge and background. This may be an advantage compared to smart contract audits that primarily rely on teams with perhaps limited or specialized expertise.
Why Solidity Testing for Smart Contracts is Essential
1) Digital Agreements are High-Value Assets
Assets with considerable value are usually held via innovative agreements. The contracts also carry decentralized finance (DeFi) and NFTs as assets. Therefore, the smallest mistake could reveal these assets, causing clients to suffer massive and irreparable losses. Therefore, testing solidity smart contracts can aid in finding flaws and fixing them before the application’s deployment.
2) Digital Assets are Immutable
The digital contracts that businesses implement into the EVM are permanent. They cannot be changed once they are deployed in the blockchain environment. Therefore, when creating their agreements, solidity testing becomes a crucial step.
Companies can find weaknesses and flaws in their contract using a variety of methodologies, such as smart contract penetration testing.
3) Validation of Behavior
Solidity testing helps developers to verify that behaviors follow agreements. The evaluation ensures that contracts function as desired by a corporation. Companies rewrite contracts and correct anomalies if they are not acting as planned.
4) Removal of Side Effects
When building smart contracts, the most recent code addition occasionally has negative impacts on the earlier work. Fortunately, pentesting smart contracts make it possible to confirm that businesses haven’t damaged any past functionality.
5) Provision of High-Quality Product
Solidity testing ensures that businesses offer their customers high-quality services. They improve the end-user experience and produce a strong brand image for a business. Smart contract testing eliminates flaws that could result in monetary loss.
6) Saves Time
Debugging assists businesses in excluding potential causes of random errors. In addition, to help them duplicate the problem, they can undertake Solidity testing. Therefore, once the issue has been resolved, development activity immediately continues.
A key part of a blockchain business is smart contracts. Testing the contracts to ensure that they satisfy a company’s goals is essential while drafting them. Digital agreement testing is vital for several reasons, as was previously explained. At the end of the day, it’s crucial to make sure the contracts are secure because they contain valuable assets.