ISTQB Chapter 4 Theories

Question 1

What are the three test techniques used to support testers in test analysis (what to test) and in test design (how to test)?

Answer 1

1. Black-box test techniques (specification-based techniques)
2. White-box test techniques (structure-based techniques)
3. Experience-based test techniques

Question 2

This test technique is based on an analysis of the specified behavior of the test object without reference to its internal structure. Therefore, the test cases are independent of how the software is implemented. Consequently, if the implementation changes, but the required behavior stays the same, then the test cases are still useful.

a. Black-box test techniques
b. White-box test techniques
c. Experience-based test techniques

Answer 2

a. Black-box test techniques (also known as specification-based techniques)

Question 3

This test techniques are based on an analysis of the test object’s internal structure and processing. As the test cases are dependent on how the software is designed, they can only be created after the design or the implementation of the test object.

a. Black-box test techniques
b. White-box test techniques
c. Experience-based test techniques

Answer 3

b. White-box test techniques (also known as structure-based techniques)

Question 4

This test techniques use the knowledge and experience of testers for the design and implementation of test cases. The effectiveness of these test techniques depends heavily on the tester’s skills.

a. Black-box test techniques
b. White-box test techniques
c. Experience-based test techniques

Answer 4

c. Experience-based test techniques

Note: Experience-based test techniques can detect defects that may be missed using the
black-box test techniques and white-box test techniques. Hence, experience-based test techniques are complementary to the black-box test techniques and white-box test techniques.

Question 5

What are the commonly used black-box test techniques?

Answer 5

1. Equivalence Partitioning
2. Boundary Value Analysis
3. Decision Table Testing
4. State Transition Testing

Question 6

This black-box test technique divides data into partition based on the expectation that all the elements of a given partition are to be processed in the same way by the test object.

a. Equivalence Partitioning
b. Boundary Value Analysis
c. Decision Table Testing
d. State Transition Testing

Answer 6

a. Equivalence Partitioning

Question 7

In Equivalence Partitioning, how do you achieve 100% coverage?

Answer 7

Test cases must exercise all identified partitions (including invalid partitions) by covering each partition at least once.

Valid partition - partition that contains valid value, or those that should be processed by the test object are as those for which the specification defines their processing.

Invalid partition - partition that contains invalid value, or those that should be ignored or rejected by the test object or as those for which no processing is defined in the test object specification.

Question 8

This refers to the number of partitions exercised by at least one test case, divided by the total number of partitions, and is expressed as a percentage.

Answer 8

Coverage

Question 9

For Equivalence Partitioning, what is Each Choice coverage and its purpose?

Answer 9

Each Choice coverage applies to a test case that is covered by multiple sets of partitions. Each Choice coverage requires test cases to exercise each partition from each set of partitions at least once.

Each Choice coverage does not take into account combinations of partitions.

Question 10

What is the theory behind the Equivalence Partitioning technique for black-box testing?

Answer 10

The expectation is that all the elements of a given partition are to be processed in the same way by the test object.

This means that a defect found in one value from an equivalence partition applies to the test of any other value from the same partition. Therefore, one test for each partition is sufficient.

Question 11

This is a black-box test technique based on exercising the boundaries of equivalence partitions.

This can only be used for ordered partitions.

a. Equivalence Partitioning
b. Boundary Value Analysis
c. Decision Table Testing
d. State Transition Testing

Answer 11

b. Boundary Value Analysis (BVA)

Question 12

What is the theory behind Boundary Value Analysis (BVA) for black box testing?

Answer 12

BVA focuses on the boundary values of the partitions because developers are more likely to make errors with these boundary values.

Typical defects found by BVA are located where implemented boundaries are misplaced to positions above or below their intended positions or are omitted altogether.

Question 13

What are the two common versions of Boundary Value Analysis (BVA)?

Answer 13

1. 2-value Boundary Value Analysis
2. 3-value Boundary Value Analysis

Question 14

In this BVA, there are two coverage items: this boundary value and its closest neighbor belonging to the adjacent partition.

a. 2-value BVA
b. 3-value BVA

Answer 14

a. 2-value BVA

Question 15

In this BVA, there are three coverage items: this boundary value and both its neighbors.

a. 2-value BVA
b. 3-value BVA

Answer 15

b. 3-value BVA

Question 16

This is measured as the number of boundary values (and its neighbors for 3-BVA) that were exercised, divided by the total number of identified boundary values (and its neighbors for 3-BVA), and is expressed as a percentage.

Answer 16

Coverage

Question 17

In Boundary Value Analysis, how do you achieve 100% coverage?

Answer 17

All coverage items has been executed

Question 18

This black-box test technique is used to testing implementation of requirements that specify how different combinations of conditions result in different outcomes.

This is an effective way of recording complex, such as business rules

a. Equivalence Partitioning
b. Boundary Value Analysis
c. Decision Table Testing
d. State Transition Testing

Answer 18

c. Decision Table Testing

Question 19

In Decision Table Testing for black box testing, what does the columns (horizontal) represent?

Answer 19

Each column corresponds to a decision rule that defines a unique combination of conditions

Question 20

What are the coverage items for Decision Table Testing for black-box testing?

Answer 20

Coverage Items are only those columns containing feasible combinations of conditions.

Question 21

How do you achieve 100% coverage for Decision Table Testing?

Answer 21

Test cases must be exercised for all columns with feasible combination of conditions.

Question 22

What are the advantages of decision table testing?

Answer 22

1. It provides a systematic approach to identify all the combinations of conditions, some of which might otherwise be overlooked.
2. It helps to find any gaps or contradictions in the requirements.

Question 23

This is a black-box testing technique that is based on state table or state diagram.

Answer 23

State Transition Testing

Question 24

What are the three coverage criteria for State Transition Testing?

Answer 24

1. All states coverage
2. Valid transitions coverage
3. All transitions coverage

Question 25

This coverage in State Transition Testing where the coverage items are the states. To achieve 100% coverage, test cases must ensure that all states are exercised.

a. All states coverage
b. Valid transitions coverage
c. All transitions coverage

Answer 25

a. All states coverage

Note: All states coverage is weaker than valid transitions coverage, because it can typically be achieved without exercising all the transitions.

Valid transitions coverage is the most widely used coverage criterion. Achieving full valid transitions coverage guarantees full all states coverage.

Achieving full all transitions coverage guarantees both full all states coverage and full valid transitions coverage and should be a
minimum requirement for mission and safety-critical software.

Question 26

This coverage in State Transition Testing is also called as 0-switch coverage, where the coverage items are single valid transitions. To achieve 100% coverage, test cases must exercise all the valid transitions.

a. All states coverage
b. Valid transitions coverage
c. All transitions coverage

Answer 26

b. Valid transitions coverage

Note: All states coverage is weaker than valid transitions coverage, because it can typically be achieved without exercising all the transitions.

Valid transitions coverage is the most widely used coverage criterion. Achieving full valid transitions coverage guarantees full all states coverage.

Achieving full all transitions coverage guarantees both full all states coverage and full valid transitions coverage and should be a
minimum requirement for mission and safety-critical software.

Question 27

This coverage in State Transition Testing is where the coverage items are all the transitions shown in a state table. To achieve 100% coverage, test cases must exercise all the valid transitions and attempt to execute invalid transitions. Testing only one invalid transition in a test case helps to avoid defect masking.

a. All states coverage
b. Valid transitions coverage
c. All transitions coverage

Answer 27

c. All transitions coverage

Note: All states coverage is weaker than valid transitions coverage, because it can typically be achieved without exercising all the transitions.

Valid transitions coverage is the most widely used coverage criterion. Achieving full valid transitions coverage guarantees full all states coverage.

Achieving full all transitions coverage guarantees both full all states coverage and full valid transitions coverage and should be a
minimum requirement for mission and safety-critical software.

Question 28

What are the two known white-box test techniques?

Answer 28

a. Statement Testing
b. Branch Testing

Question 29

What is the value of white-box testing?

Answer 29

a. Its fundamental strength is that the entire software implementation is taken into account during testing, which facilitates defect detection even when the software specification is vague, outdated or incomplete.

b. White-box test techniques can be used in statis testing (e.g. during dry runs of code). It is well suited to reviewing code not yet ready for execution, pseudocode and other high-level or town-down logic which can be modeled with a control flow graph.

c. Performing only black-box testing does not provide a measure of actual code coverage. White-box coverage measures provide an objective measurement of coverage and the necessary information to allow additional tests to be generated to increase the coverage, and subsequently increase confidence in the code.