ISTQB CTAL-TTA Practice Test - Questions Answers, Page 3

The earliest stage in the application's SDLC at which performance efficiency testing can be performed is during requirements analysis. At this stage, performance requirements and goals are established, providing a baseline for what needs to be tested and verified throughout the later stages of development.

An ISTQB defined technique for identifying risks when defining a risk-based approach to testing the performance efficiency of a new application is to analyze the requirements to look for areas where performance efficiency requirements have not been well-defined. This technique ensures that testing efforts are focused on areas of the application that are critical for performance but may have insufficient coverage in terms of detailed requirements.

Cyclomatic complexity is a measure of the number of linearly independent paths through a program's source code. Segment 3 has two conditions: if (a > b) or (c < d) and the associated else. This structure introduces multiple decision points, thereby increasing the number of potential execution paths. Comparatively, the other segments have fewer conditions and straightforward loops, which contribute to a lower cyclomatic complexity. Segment 3, with its compound condition and branching logic, likely has the highest cyclomatic complexity.

To achieve decision coverage, each branch of the decision structure in the code must be executed at least once. The code snippet has three branches:

withdrawal-amount <= amount-on-deposit

withdrawal-amount <= $100 AND preferred-customer = true

Default case where the transaction is not authorized

Data set #1 triggers the second branch because the withdrawal amount is not less than the amount on deposit, but it is less than $100, and the user is a preferred customer.

Data set #2 triggers the first branch where the withdrawal amount is equal to the amount on deposit.

Data set #3 tests the condition where the withdrawal amount is less than the deposit amount, but the user is not a preferred customer, triggering the default case.

All decision branches are covered by these test cases, achieving 100% decision coverage.

Maintainability metrics typically used with static analysis include measures that reflect the complexity and understandability of the code, such as Number of Lines of Code (LOC), Number of Function Calls, and Comment Frequency. These metrics help in assessing how easily the software can be understood, modified, and maintained. Mean Time Between Failures (MTBF), on the other hand, is a reliability metric. It measures the time elapsed between inherent failures of a system during operation. MTBF is used to predict the system's reliability and is not directly related to the maintainability of the code. Reliability metrics like MTBF would be used in the testing phase to measure the operational reliability of the system rather than during static analysis for maintainability assessment.

In the context of safety-critical systems, particularly in the medical domain, reliability is of utmost importance. For such systems, it is crucial to ensure that the software can handle unexpected input values and continue to operate without failure. This is essential to ensure patient safety and compliance with FDA requirements. Vulnerability scans (option A) are more related to security testing, whereas scalability (option C) and installation/de-installation (option D) are important but not specifically related to the reliability and safety criticality of the system in the medical domain.

The characteristics listed in the question point towards the need to manage synchronization between processes and make efficient use of limited hardware resources, such as microcontrollers and timeslots. Additionally, the complexity and concurrency of tasks highlight the importance of the software's performance over time. Time-behaviour testing is the most appropriate non-functional test type to perform in this scenario as it focuses on evaluating the timing aspects of the system, such as response times, processing times, and throughput rates. It ensures that the system meets its time-related requirements, which is critical for systems reliant on synchronization and limited by hardware performance constraints.

The pseudo code provided for the Price program shows a potential for an infinite loop due to the way the 'Del_Charge' variable is being manipulated. The loop is set to continue 'WHILE Del_Charge > 0', and within the loop, 'Del_Charge' is initially set to 5 and then potentially decreased by 2 if 'Sale_Value > 60000'. However, at the end of each loop iteration, 'Del_Charge' is increased by 1. This means that if 'Sale_Value' is not greater than 60000, 'Del_Charge' will not decrease and will instead increment indefinitely, causing an infinite loop. Even if 'Sale_Value' is greater than 60000, the decrement by 2 could be negated by the subsequent increments if the loop runs enough times, potentially leading to an infinite loop situation. There is no guaranteed exit condition once the loop is entered, which is a control flow anomaly.

Portability testing is concerned with how well software can be transferred from one environment to another. In the context of a bank using COTS (Commercial Off-The-Shelf) software, the sub-characteristic of replaceability becomes particularly relevant. This is because the bank does not want to create a dependency on any external COTS supplier, meaning it should be able to replace the software with another product without significant effort or operational disruption. Replaceability ensures that if needed, the bank can switch to different software, thereby mitigating the risk of supplier dependency.