Apex Assert Class

In plain words: Checkpoints capture a complete snapshot of in-memory heap data and SOQL queries at a specific line of code without cluttering your logic with debug statements. Assertions are automated sanity checks that verify whether your code's real behavior matches your expected outcome. Diagnosing tricky edge cases and preventing regressions requires more than adding temporary System.debug() lines. Salesforce arms developers with two essential diagnostic tools: Checkpoints (detailed heap inspection during execution) and the modern Assert class (programmatic condition validation in unit tests and business logic). Mastering both helps you validate architectural assumptions and debug complex codebases faster.