How Can an Invariant Be Checked during a Unit Test?

An invariant can be checked during a unit test by creating a special function within the test suite that asserts the invariant's condition is true at critical points of execution. After every state-changing function call (e.g. deposit, withdraw, transfer), the test suite calls the invariant check function.

If the invariant (e.g. total supply equals sum of balances) returns false at any point, the test immediately fails, signaling a bug. This ensures that the core financial rules are maintained throughout the test execution.

How Are Vega and Gamma Used Together in a Portfolio’s Risk Analysis?
What Are the Differences between Single-Function and Cross-Function Reentrancy Attacks?
How Does True Fungibility Benefit a Currency?
What Is the Primary Difference between a ‘View’ Function and a ‘State-Changing’ Function?
What Is the Relationship between an ‘Invariant’ and a ‘Safety Property’?
How Does a Miner Choose Which Transactions to Include from the Mempool?
How Do State Variables Protect against Unexpected External Calls?
How Long Does It Typically Take for the Bitcoin Network’s Difficulty to Adjust after a Major Drop in Hash Rate?

Glossar