ISTQB ISTQB-AL-TA Free Practice Questions — Page 3

Correct Answer: A. Finite state machines are used to describe the intended execution-time behavior of a software-controlled system.

In model-based testing, a model (commonly a finite state machine, UML state diagram, or similar notation) formally describes the expected runtime behavior of the system. The testing tool then uses this model to derive test cases systematically. Option B is incorrect — MBT generates structured, model-driven test cases, not random threads; random generation describes random testing, not MBT. Option C is incorrect — MBT does not aim for full code coverage; it derives tests from behavioral models, not source code structure. Option D is incorrect — MBT tools generate and manage test cases from the model; they do not simply "execute the model" as a runtime engine. The defining characteristic of MBT tools is test case generation from a behavioral model.

Correct Answer: B. 10

In State Transition Testing, an invalid transition occurs when an event (input) happens in a state where that event is not defined. To calculate this, you identify all possible events in the system and see which ones are "missing" from each specific state. Identify the Events: There are 5 unique events in this diagram: Start, Next, Back, Refresh, and Complete. Analyze the States: There are 4 states: Menu, Screen 1, Screen 2, and Screen 3. Calculate Total Possibilities: 4 states × 5 events = 20 potential transitions. Subtract Valid Transitions: Looking at the diagram, there are 10 defined (valid) arrows. Result: 20−10=10 invalid transitions. For example, "Complete" is invalid from Screen 1, and "Start" is invalid from Screen 2.

Correct Answer: C. 7

A 1-switch transition (also known as N-switch where N=1) refers to a sequence of two consecutive valid transitions (three states in a row). The question asks for all sequences starting specifically from Screen 1. From Screen 1, the valid first "hops" (0-switch) are: Refresh (loops back to Screen 1) Next (goes to Screen 2) Back (goes to Menu) Now, we calculate the second "hop" for each to find the 1-switch sequences: From Refresh (back in Screen 1): Refresh -> Refresh Refresh -> Next Refresh -> Back From Next (now in Screen 2): Next -> Refresh Next -> Next (to Screen 3) Next -> Back (to Screen 1) From Back (now in Menu): Back -> Start (to Screen 1)

Correct Answer: B. 62

The correct answer is B. In Pairwise (All-Pairs) Testing, the number of pair combinations is the sum of the products of each pair of parameters. To calculate this, you look at every possible combination of two variables. Parameters: Colour (4), Model (3), Gigabytes (4), Connectivity (2). Pairs to calculate: Colour & Model: 4×3=12 Colour & Gigabytes: 4×4=16 Colour & Connectivity: 4×2=8 Model & Gigabytes: 3×4=12 Model & Connectivity: 3×2=6 Gigabytes & Connectivity: 4×2=8 Total: 12+16+8+12+6+8=62.

Correct Answer: D. 16

To find the minimum number of test cases for pairwise coverage, a common "rule of thumb" (and the method used in ISTQB scenarios) is that the number of test cases is often determined by the product of the two largest parameters. The two largest parameters are Colour (4) and Gigabytes (4). 4×4=16. While sophisticated algorithms can sometimes reduce this slightly, in a certification context, you look for the matrix that can accommodate all pairs of the largest sets. Option D ensures that every possible combination of Colour and Gigabytes is covered at least once, while the smaller parameters (Model and Connectivity) are "slotted in" to complete the pairs.