Explanation / Rationale

a) Is correct. Test design involves using test conditions to create test cases and other necessary testware, such as test data requirements and test charters for exploratory testing. Test environment requirements are also specified, including the necessary infrastructure and tools
b) Is not correct. Test execution involves executing test cases (as part of test procedures), however it does not directly cover the other testware mentioned in the question, such as test data requirements, test environment requirements and test conditions
c) Is not correct. Test analysis is used to identify the features that require testing. The test basis is analyzed and defined as test conditions, which are then prioritized along with related risks. While this activity involves working with test conditions, it does not cover the other testware mentioned in the question, such as test data requirements, test environment requirements and test cases
d) Is not correct. Test implementation includes the generation of test procedures, such as manual and automated test scripts, which are created from test cases and may be assembled into test suites. Test procedures are prioritized and arranged in a test execution schedule. Test data is created, and the test environment built, and its set up verified. While this activity involves explicitly working with test cases, and may use test data requirements and test environment requirements to create test data and the test environment, it does not cover test conditions

Explanation / Rationale

Branch testing is a white-box test technique in which the coverage items are branches. A branch is a transfer of control between two nodes in the control flow graph, which shows the possible sequences in which source code statements are executed in the test object. Each transfer of control can be either unconditional (i.e., straight-line code) or conditional (i.e., a decision outcome). Coverage is measured as the number of branches exercised by the test cases divided by the total number of branches, and is expressed as a percentage.
Thus:
a) Is not correct. A decision outcome is a conditional branch. For branch testing, X counts not only conditional, but also unconditional branches
b) Is not correct. Branch coverage counts not only conditional, but also unconditional branches
c) Is correct. Branch coverage is measured as the number of branches exercised by the test cases divided by the total number of branches, and is expressed as a percentage
d) Is not correct. Both X and Y count only conditional branches and do not take into account the unconditional branches

Explanation / Rationale

a) Is not correct. This is an example of a risk monitoring activity, not risk analysis
b) Is not correct. This is an example of an architectural decision, not related with testing
c) Is not correct. This is an example of performing a quantitative risk analysis and is not related to thoroughness or scope of testing
d) Is correct. This shows how risk analysis impacts the thoroughness of testing (i.e., the level of detail)

Explanation / Rationale

a) Is not correct. Risk impact and risk likelihood are independent
b) Is not correct. Risk impact and risk likelihood are independent
c) Is correct. Risk impact and risk likelihood are independent
d) Is not correct. We need both factors to calculate risk level

Explanation / Rationale

a) Is correct. The client is in a different location and time zone, so it may be difficult to communicate face-to-face
b) Is not correct. Dashboards are usually available to any user at any time, so the difference in time zones will not be as much of a hindrance to communication as verbal, face-to-face communication
c) Is not correct. Although the time difference between Europe and America is several hours, and this may cause some inconvenience, it's certainly not as great as with communicating face-to-face
d) Is not correct. Video conferencing tools are a convenient means of communication. Although communication between Europe and America during working hours usually requires one party to connect in the very early or very late hours, this is not as much of an inconvenience as verbal, face-to-face communication

Explanation / Rationale

a) Is correct. It is important that testers are involved from the beginning of the software development lifecycle (SDLC). It will increase understanding of design decisions and will detect defects early.
b) Is not correct. Both developers and testers will have more understanding of each other's work products and how to test the code
c) Is not correct. End users will not help the testers in increasing the quality of defect reports; also, users usually do not participate in low-level testing levels like integration testing
d) Is not correct. Being certified does not automatically mean that the tester will be better in test design

Explanation / Rationale

The following three transitions:

“REQUESTING -> CONFIRMED”
“WAITING LIST -> CONFIRMED”
“WAITING LIST -> END”

cannot appear in the same test case, which suggests that at least three test cases are required. All the other transitions can appear in combination with one or more of these three transitions, so we need a minimum of three test cases. In fact, only three sequences are possible:

TC1: START (Room request) → REQUESTING (Available) → CONFIRMED (Pay) → END
TC2: START (Room request) → REQUESTING (Not available) → WAITING LIST (Available) → CONFIRMED (Pay) → END
TC3: START (Room request) → REQUESTING (Not available) → WAITING LIST (Cancel) → END

Thus:
a) Is correct
b) Is not correct
c) Is not correct
d) Is not correct

Explanation / Rationale

According to the dependencies, SEARCH tests must be executed first, then VIEW tests, then ADD tests and, at the end, ORDER tests. Within each of these groups the order is determined by the priorities of the test cases.
So, TC1 must be executed first, then TC2, then TC4 followed by TC3, and then TC5 as the last one.
So, the ordering is: TC1, TC2, TC4, TC3, TC5.
Thus:
a) Is correct. TC3 will be the fourth test case executed
b) Is not correct
c) Is not correct
d) Is not correct

Explanation / Rationale

a) Is not correct. Quality should be the responsibility of everyone working on the project and not the sole responsibility of the test team
b) Is not correct. First, it is not a benefit if an external test team does not meet delivery deadlines, and second, there is no reason to believe that external test teams will feel they do not have to meet strict delivery deadlines
c) Is not correct. It is bad practice for the test team to work in complete isolation, and we would expect an external test team to be concerned with changing project requirements and communicating well with developers
d) Is correct. Specifications are never perfect, meaning that assumptions will have to be made by the developer. An independent tester is useful in that they can challenge and verify the assumptions and subsequent interpretation made by the developer

Explanation / Rationale

a) Is correct. This test covers two acceptance criteria: one about editing the document and one about saving changes
b) Is not correct. Acceptance criteria cover the editor activities, not the content owner activities
c) Is not correct. Scheduling the edited content for publication may be a nice feature, but it is not covered by the acceptance criteria
d) Is not correct. Acceptance criteria state about reassigning from an editor to the content owner, not to another editor

Explanation / Rationale

a) Is correct. Test automation can provide measures that are too complicated for humans to derive, such as white-box test coverage measures for all but the most trivial code
b) Is not correct. By using test tools the responsibility for the testing is NOT shared with the tool vendor as the vendor is not involved in the testing, and it is the tester’s responsibility. The only possible responsibility that could be assigned to the tool vendor is if the tool fails to work as expected and provides incorrect test results
c) Is not correct. Testers still need to perform critical thinking when analyzing anomalies in the test results to determine their likely cause
d) Is not correct. Neither testers nor tools can generate test cases simply from an analysis of the program code as the code is the implementation and provides no information on the expected results, which will need to come from another part of the test basis, such as the design specification

Explanation / Rationale

The equivalence partitions are: {…, 99, 100}, {101, 102, …, 198, 199}, {200, 201, …}.
Thus, there are 4 boundary values, which are: 100, 101, 199 and 200.
In 2-value BVA, for each boundary value there are two coverage items (the boundary value and its closest neighbor belonging to the adjacent partition). As the closest neighbors are also boundary values in the adjacent partition, then there are just four coverage items.

Thus:
a) Is not correct. Only 100 and 200 are valid coverage items for 2-value BVA, so we achieve 50% coverage
b) Is not correct. Only 100 and 200 are valid coverage items for 2-value BVA, so we achieve 50% coverage
c) Is not correct. Only 100 and 101 are valid coverage items for 2-value BVA, so we achieve 50% coverage
d) Is correct. 101, 199 and 200 are valid coverage items for 2-value BVA, so we achieve 75% coverage

Explanation / Rationale

a) Is correct. Behavior-Driven Development (BDD) is a well-known example of a test-first approach to development
b) Is not correct. Test Level Driven Development is not a correct example of a test-first approach to development
c) Is not correct. Function-Driven Development is not a correct example of a test-first approach to development
d) Is not correct. Performance-Driven Development is not a correct example of a test-first approach to development

Explanation / Rationale

a) Is correct. Since 100% statement coverage is achieved, every statement, including the ones with defects, must have been executed and evaluated at least once
b) Is not correct. Coverage depends on what is tested, not on the number of test cases. For example, for code “if (x==0) y=1”, one test case (x=0) achieves 100% statement coverage, but two test cases (x=1) and (x=2) together achieve only 50% statement coverage
c) Is not correct. If there is a loop in the code there may be an infinite number of possible paths, so it is not possible to execute all the possible paths in the code
d) Is not correct. Exhaustive testing is not possible (see the seven testing principles section in the syllabus). For example, for code “input x; print x” any single test with arbitrary x achieves 100% statement coverage, but covers one input value

Explanation / Rationale

a) Is not correct. The approval of the budget is an example of an entry criterion. It would make no sense to approve the budget for some activity that has already been done
b) Is correct. Running out of budget can be viewed as a valid exit criterion
c) Is not correct. Availability of resources is an example of an entry criterion for testing
d) Correct. Coverage is a measure of thoroughness, so it is a typical exit criterion
e) Is not correct. This is an example of an entry criterion, checked before the project starts

Explanation / Rationale

a) Is not correct. Although it is correct to say that in Agile software development, some of the test management tasks may be handled by the Agile team itself, the testing role is not primarily the responsibility of a single individual from outside the team. Instead the testing is more likely to be performed by various team members following the whole-team approach
b) Is not correct. The test management role primarily involves activities related to test planning, test monitoring and control, and test completion. So, although this statement is partially correct, it is wrong to say that the testing role is primarily responsible for test monitoring and control
c) Is correct. In Agile software development, some of the test management tasks may be handled by the Agile team itself. However, for test activities that span multiple teams within an organization, test managers outside of the development team may perform these tasks
d) Is not correct. The test management role primarily involves activities related to test planning, test monitoring and control, and test completion, while the testing role is primarily responsible for the technical and engineering aspects of testing, such as test analysis, test design, test implementation, and test execution. Thus the test management role is not normally responsible for test analysis and test design, although it is correct to say that the testing role is primarily responsible for test implementation and execution

Explanation / Rationale

a) Is not correct. Most work products can be examined using some form of static testing, and a contract must be interpretable by humans and so could be reviewed, which is a form of static testing
b) Is not correct. Most work products can be examined using some form of static testing, and a test plan must be interpretable by humans and so could be reviewed, which is a form of static testing
c) Is correct. Most work products can be examined using some form of static testing; however it is not suitable for work products that are too complex for human interpretation and should not be analyzed by tools, and encrypted code is too complex for humans and if it is properly encrypted it will not be analyzable by most tools
d) Is not correct. Most work products can be examined using some form of static testing, and a test charter must be interpretable by humans and so could be reviewed, which is a form of static testing

Explanation / Rationale

a) Is correct. Each test level has specific and distinct test objectives as a different form of test object (e.g., single component, complete system) is tested at each test level and overlapping test objectives would lead to unnecessary duplication
b) Is not correct. Test analysis and design for a given test level should start during the corresponding development phase to facilitate early testing (e.g., acceptance test analysis and design should begin during requirements analysis). Test implementation will generally start later, and test execution will start during the test level
c) Is not correct. Test design for a given test level should start during the corresponding development phase to facilitate early testing, however test design (e.g., test case generation) needs to be based on an agreed test basis, not an early draft, otherwise significant test effort may be wasted on creating test cases for a design that later changes
d) Is not correct. Quality control applies to all development activities, meaning that every software development activity has a corresponding test activity. However, the same symmetry does not apply to dynamic and static testing. There are some static testing activities (e.g., static analysis) for which there is no obvious corresponding dynamic testing activity

Explanation / Rationale

a) Is correct. This is something that can (and should) be checked before the code is submitted to version control
b) Is not correct. This is something that can be checked after step (2) is performed, because merge conflict reporting can be done after the code is submitted and merged
c) Is not correct. This fits better as the entry criterion for step (3)
d) Is not correct. This fits better as the exit criterion for step (3)

Explanation / Rationale

Considering each of the listed review types:

1. Technical review - This type of review is performed by technically qualified reviewers and led by a moderator. The objectives are to gain consensus and make decisions on technical problems while also evaluating quality and building confidence in the work product, generating new ideas, motivating and enabling authors to improve, and detecting anomalies
2. Informal review - The main objective is to detect anomalies. The process is not defined and does not require formal documented output
3. Inspection - This is the most formal review type, and it follows the complete generic review process. The primary objective is to find the most anomalies, and other objectives include evaluating quality and building confidence in the work product, motivating and enabling authors to improve, and collecting metrics that can be used to enhance the software development life cycle (SDLC), including the inspection process. The author cannot act as the review leader or scribe
4. Walkthrough - Led by the author, this type of review serves various objectives such as evaluating quality and building confidence in the work product, educating reviewers, gaining consensus, generating new ideas, motivating and enabling authors to improve, and detecting anomalies. Reviewers might perform an individual review before the walkthrough, but this is not mandatory

A. Includes objectives such as gaining consensus, generating new ideas, and motivating authors to improve (A)
B. The main objective is detecting potential defects and it generates no formal documented output (D)
C. The main objective is detecting potential defects and it requires metrics collection to support process improvement (C)
D. Includes objectives such as educating reviewers, gaining consensus, generating new ideas and detecting potential defects (B)

Thus:
a) Is not correct
b) Is correct. The correct match is: 1A, 2D, 3C, 4B
c) Is not correct
d) Is not correct

Explanation / Rationale

a) Is correct. Product quality metrics measure quality characteristics. Mean time to failure measures maturity, so it is a product quality metric
b) Is not correct. This is an example of a defect metric, not a product quality metric
c) Is not correct. This is an example of a coverage metric, not a product quality metric
d) Is not correct. This is an example of a defect metric, not a product quality metric

Explanation / Rationale

In the three-point estimation technique:

E = (optimistic + 4*most likely + pessimistic)/6

E = (2+(4*11)+14)/6 = 10

Thus:
a) Is not correct
b) Is not correct
c) Is not correct
d) Is correct

Explanation / Rationale

a) Is not correct. QA concentrates on process improvement and implementation, using a preventive approach to avoid errors and defects, while testing is a form of QC that is used to detect defects
b) Is correct. QC aims to achieve appropriate levels of quality by focusing on identifying and correcting product defects. Testing is a significant part of QC and helps to uncover these defects
c) Is not correct. Although testing is a significant part of QC and helps to uncover defects, other (non-testing) techniques utilized in QC include formal methods like model checking and proof of correctness, as well as simulation and prototyping
d) Is not correct. QA concentrates on process improvement and implementation, using a preventive approach to avoid errors and defects, while testing is a form of QC that is used to detect defects

Explanation / Rationale

Using the three-point estimation technique, the final estimate (E) is calculated as:

E = (a + 4*m + b) / 6,

where a is the most optimistic estimate, m is the most likely estimate, and b is the most pessimistic estimate.

Thus:
a) Is correct. In this case, the estimate for executing a single test case is:

E = (1h + 4*3h + 8h) / 6 = 3.5 hours

So, the total time needed for the tester to execute 4 test cases is:

3.5h * 4 = 14 hours

b) Is not correct
c) Is not correct
d) Is not correct

Explanation / Rationale

The average development effort is $900,000 and the average test effort is $90,000 (calculated from the four projects).
The average test-to-development effort ratio is 1:10 ($90,000 : $900,000), which means that historically, on average, the test effort is 10% of the development effort.
So if the development effort is estimated to be $800,000, the estimated test effort is estimated as:

10% * $800,000 = 0.1 * $800,000 = $80,000.

Thus:
a) Is not correct
b) Is correct
c) Is not correct
d) Is not correct

Explanation / Rationale

a) Is not correct. Coverage is always defined as the percentage of the covered elements. Therefore, it cannot exceed 100%
b) Is correct. If the statements executed by T1 and T2 were disjoint, the coverage of the test suite {T1, T2} would be 105%, which is impossible (see answer a). Therefore, at least 5% of executable statements must have been executed by both T1 and T2
c) Is not correct. Statement coverage does not tell us anything about the number of non-executable statements in the code
d) Is not correct. Even if a test suite achieves full statement coverage, this does not imply achieving full branch coverage

Explanation / Rationale

Considering the attributes:

• Specified for walkthroughs, technical reviews, and inspections; thus, the reviews being performed cannot be informal reviews
• The purpose of evaluating quality is one of the most important objectives of a walkthrough
• This is not allowed for inspections and is typically not done in technical reviews. A moderator is needed in walkthroughs and is allowed for informal reviews
• All types of reviews can include individual preparation (even informal reviews)
• All types of reviews can produce a review report, although informal reviews do not require documentation

Thus:
a) Is not correct
b) Is correct
c) Is not correct
d) Is not correct

Explanation / Rationale

Exploratory testing is useful when there are few or inadequate specifications or there is significant time pressure on the testing. Exploratory testing is also useful to complement other more formal test techniques. Exploratory testing will be more effective if the tester is experienced, has domain knowledge and has a high degree of essential skills, like analytical skills, curiosity and creativeness.

Thus:
a) Is correct. Exploratory testing is useful when there are few or inadequate specifications or there is significant time pressure on the testing
b) Is not correct. Exploratory testing is not a black-box test technique
c) Is not correct. Exploratory testing is useful when the specifications are poorly written
d) Is not correct. Programming skills have nothing to do with exploratory testing in principle
e) Is correct. Exploratory testing will be more effective if the tester is experienced, has domain knowledge and has a high degree of essential skills, like analytical skills, curiosity and creativeness

Explanation / Rationale

a) Is not correct. It is more often used in behavior-driven development (BDD)
b) Is not correct. It is the description of test-driven development (TDD)
c) Is correct. In acceptance test-driven development (ATDD) tests are written from acceptance criteria as part of the design process
d) Is not correct. It is used in BDD

Explanation / Rationale

a) Is not correct. One of the purposes of retrospectives is to identify potential process improvements, which, if put into practice, should result in the quality of future outputs of the development process (test objects) being higher. So, this is likely to occur as a result of a retrospective
b) Is not correct. A benefit of retrospectives for testing includes increased test efficiency through process improvements. So, this is likely to occur as a result of a retrospective
c) Is correct. Participants at retrospectives typically include testers, developers, architects, product owners, and business analysts, but end users are rarely invited or attend these meetings – and they are also unlikely to receive any reports from these meetings. So, it is very unlikely that they will learn and understand more about the development and test processes through retrospectives
d) Is not correct. A benefit of retrospectives for testing includes improved quality of testware (including automated test scripts) through joint reviews with developers. So, this is likely to occur as a result of a retrospective

Explanation / Rationale

a) Is not correct. Impediments to testing can be high level and business-related, so this is an important piece of information for business stakeholders
b) Is correct. Branch testing is a technical metric used by developers and technical testers. This information is of no interest to business representatives
c) Is not correct. Test progress is project related, so it may be useful for business representatives
d) Is not correct. Risks impact product quality, so it may be useful for business representatives

Explanation / Rationale

The ‘exhaustive testing is impossible’ principle is concerned with the fact that it is not feasible to test every possible variation of test inputs in all different circumstances, except in trivial cases. Instead, testing utilizes test techniques, test case prioritization, and risk-based testing to sample from the set of possibilities and focus testing efforts.
a) Is not correct. The principle states that it is not feasible to test everything except in trivial cases. Testing everything would require testing every possible variation of test inputs in all different circumstances, which is generally infeasible as there will be a practically infinite number. Testing every possible specified output will not address this problem as the relationship between inputs and specified outputs can be different for each test object. Sometimes there may be a practically infinite number of possible specified outputs (e.g., when there are several variables representing real numbers), whereas at other times there may be just two specified outputs, such as with a single variable that can be either true or false
b) Is not correct. The principle states that it is not feasible to test every possible variation of test inputs in all different circumstances. This is because for non-trivial systems there is a practically infinite number. Therefore, in practice, documenting all possible test input variations would be impractical as it would take an infinite length of time
c) Is not correct. Starting testing as early as possible with reviews and other static testing approaches will not address the problem of there being too many possible test cases. The ‘early testing saves time and money’ principle is concerned with fixing defects early on to prevent the occurrence of subsequent defects in derived work products, thereby reducing costs and the likelihood of failures
d) Is correct. The use of equivalence partitioning and boundary value analysis to generate test cases is one way to address the principle as these test techniques provide a systematic way to derive a finite subset of all possible test cases

Explanation / Rationale

a) Is correct. Defect management is no less expensive. Finding and fixing defects later in SDLC is more costly
b) Is not correct. This is a benefit of static testing
c) Is not correct. This is a benefit of static testing
d) Is not correct. This is a benefit of static testing

Explanation / Rationale

Error guessing is about anticipating the errors, defects and failures based on the tester’s knowledge.
a) Is not correct. This is an example of anticipating the developer’s error
b) Is not correct. This is an example of anticipating the defect
c) Is correct. This is an example of a potential root cause of a defect, which is neither an error, defect nor failure, and difficult for the tester to anticipate
d) Is not correct. This is an example of anticipating a failure, perhaps based on experience of previous systems in this application domain

Explanation / Rationale

a) Is not correct. In this case one test case is still needed since there is at least one (unconditional) branch to be covered
b) Is not correct. Covering only unconditional branches does not imply covering all conditional branches
c) Is not correct. 100% branch coverage implies 100% statement coverage, not otherwise. For example, for an IF decision without the ELSE, one test is enough to achieve 100% statement coverage, but it only achieves 50% branch coverage
d) Is correct. Each decision outcome corresponds to a conditional branch, so 100% branch coverage implies 100% decision coverage

Explanation / Rationale

Considering each of the listed tool categories:

i. Collaboration tools – facilitate communication. Communication does not include the facilitation of test execution
ii. DevOps tools - support the DevOps delivery pipeline, workflow tracking, automated build process(es) and CI/CD. The delivery pipeline and CI/CD both include the facilitation of test execution, such as component testing for CI
iii. Management tools – increase the test process efficiency by facilitating management of the SDLC, requirements, tests, defects and configuration. The management of these items does not include the facilitation of test execution
iv. Non-functional testing tools – allow the tester to perform non-functional testing that is difficult or impossible to perform manually. Non-functional testing can include both static testing and dynamic testing, including test execution
v. Test design and implementation tools – facilitate generation of test cases, test data and test procedures. The generation of this testware does not include the facilitation of test execution

Thus:
a) Is not correct
b) Is correct. Both DevOps tools (ii) and Non-functional testing tools (iv) facilitate test execution
c) Is not correct
d) Is not correct

Explanation / Rationale

a) Is not correct. This is a common characteristic of white-box test techniques. Test conditions, test cases, and test data are derived from a test basis that may include code, software architecture, detailed design, or any other source of information regarding the structure of the software.
b) Is not correct. This is a common characteristic of white-box test techniques. Coverage is measured based on the items tested within a selected structure and the technique applied to the test basis
c) Is correct. This is a common characteristic of experience-based test techniques. This knowledge and experience include expected use of the software, its environment, likely defects, and the distribution of those defects is used to define tests
d) Is not correct. This is a common characteristic of black-box test techniques. Test cases may be used to detect gaps within requirements and the implementation of the requirements, as well as deviations from the requirements

Explanation / Rationale

a) Is not correct. DevOps generally increases the visibility of non-functional quality characteristics, such as performance and reliability
b) Is not correct. Automated processes like continuous integration/continuous delivery (CI/CD) used in DevOps facilitate stable test environments
c) Is not correct. Automated processes like CI/CD used in DevOps generally reduce the need for manual testing
d) Is correct. DevOps implementation can pose several risks and challenges, including the need to define and set up the delivery pipeline, introduce and maintain CI/CD tools, and establish and maintain test automation

Explanation / Rationale

a) Is not correct. Decision table testing is a black-box test technique, so it is specification-based, not structure-based – the test cases are not based on the decisions in the source code. In branch testing, the test cases are derived from knowledge of the control flow of the test object
b) Is not correct. Anticipation of potential defects is used in error guessing (an experience-based test technique), not in branch testing (a structure-based technique). In decision table testing, the test cases are derived from the specification that describes the business logic
c) Is not correct. If a test case is based on the knowledge of the control flow of the test object, it is a white-box test technique. Decision table testing is typically based on an analysis of business logic, so it is a black-box test technique. In branch testing, test cases are not derived from the specification – this would make it a black-box test technique. Branch testing is a white-box test technique, where test cases are derived based on the source code structure
d) Is correct. Decision table testing is a black-box test technique, so it 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. Branch testing is a white-box test technique, so test cases 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 and coded, they can only be created after the design or implementation of the test object

Explanation / Rationale

The ‘absence-of-defects fallacy’ is concerned with the idea that ensuring correctness in accordance with the requirements (i.e., verifying the absence of implementation defects) does not guarantee user satisfaction with the system. To address this it is also necessary to validate that the system meets users' needs and expectations, fulfills business objectives, and outperforms competing systems.
a) Is not correct. The ‘testing shows the presence, not the absence of defects’ principle explains that while testing can detect the existence of defects in the test object, it is not possible to demonstrate that there are no defects and, therefore, guarantee its correctness. Therefore, explaining that it is not possible for testing to show the absence of defects would partially address this principle, not the ‘absence-of-defects’ fallacy
b) Is correct. By supporting the end user to perform acceptance testing it should be possible to validate that the system meets users' needs and expectations
c) Is not correct. It is not possible to ensure that no implementation defects remain in the delivered system as the ‘testing shows the presence, not the absence of defects’ principle explains that while testing can detect the existence of defects in the test object, it is not possible to demonstrate that there are no defects and, therefore, guarantee its correctness
d) Is not correct. Modifying tests that cause no failures to ensure few defects remain is one way to address the ‘tests wear out’ principle. This principle is concerned with the idea that repeating identical tests on unaltered code is unlikely to uncover novel defects and therefore, modifying tests may be essential. This will not validate that the system meets users' needs and expectations