What approach involves ranking possible errors by risk level to design tests?

The approach that involves ranking possible errors by risk level to design tests is often referred to as Fault Attack. This method focuses on identifying the most critical areas of the application that are likely to fail or harbor defects, thereby allowing testers to prioritize their efforts based on the potential impact these faults could have on the overall system. By assessing the risk associated with different types of failures, testers can create test cases that target the most critical functionalities first, which is a risk-based testing strategy. This maximizes the effectiveness of the testing process by concentrating resources where they are needed most.

In contrast, the other methods mentioned, such as exploratory testing or dynamic testing, do not inherently involve a systematic ranking of errors based on risk. Exploratory testing emphasizes tester creativity and experience to identify defects without prior test cases, while dynamic testing focuses on executing code and observing its behavior. Static analysis involves examining code without executing it to find vulnerabilities but does not typically involve ranking errors by risk as part of the testing design process.