Unit testing refers to a type of testing specific to a software unit and component in isolation. Unit tests help ensure that code in a contract is written according to functional and technical requirements. When each of the smallest components is tested under different scenarios and passes successfully, other important tests such as integration tests can be performed to test multiple components.
As mentioned before, Truffle generates a test folder and all test files should be placed in this folder. Tests can be written in JavaScript as well as Solidity. Since this is a book on Solidity, tests are focused on writing using Solidity.
Tests in Solidity are written by authoring contracts and saved as a Solidity file. The name ...