Software Quality Assurance Flashcards

Question 1

What is the difference between quality assurance and quality control?

Accepted Answer

Quality assurance is a process-focused activity that aims to prevent defects by improving how software is planned, built, and reviewed. Quality control is product-focused and detects defects by examining the finished work, such as through testing and inspection. Assurance builds confidence in the process, while control checks the output.

Question 2

Why is it cheaper to find a defect early in development?

Accepted Answer

Defects found early are usually cheaper to fix because the code involved is fresh in the developer's mind and fewer other components depend on it. A defect found after release may require investigation, a patch, customer communication, and retesting. Early review of requirements and designs therefore prevents expensive rework later in the project.

Question 3

What is a defect, and how does it differ from a failure?

Accepted Answer

A defect is a flaw in the software's code, design, or documentation, such as a wrong condition in code. A failure is an observable incorrect behavior that occurs when a defect is executed under certain conditions. A single defect may cause no failure at all until a specific input or environment triggers it.

Question 4

How do verification and validation differ in software quality assurance?

Accepted Answer

Verification checks that the software is built correctly, meaning it conforms to its specifications, designs, and standards. Validation checks that the right software is being built, meaning it satisfies the real needs of users and stakeholders. A product can pass verification and still fail validation if the requirements themselves were misunderstood.

Question 5

What is a test oracle, and why does a tester need one?

Accepted Answer

A test oracle is any source that tells the tester what the correct result should be for a given input. Common oracles include requirements documents, specifications, user manuals, and domain knowledge. Without an oracle, a tester can run a test and observe output but cannot decide whether that output is right or wrong.

Question 6

What is the purpose of a requirements review in quality assurance?

Accepted Answer

A requirements review examines requirement documents with stakeholders to find ambiguity, contradictions, missing details, and untestable statements before design begins. Because requirements shape every later activity, errors caught here are among the least expensive to correct. Reviews also create a shared understanding among developers, testers, and customers about what the product must do.

Question 7

What is a quality attribute, and can you give an example?

Accepted Answer

A quality attribute is a property of software, beyond its basic functions, that describes how well the system behaves. Examples include reliability, performance efficiency, security, usability, maintainability, and portability. These attributes are often called nonfunctional requirements, and they are usually specified with concrete targets, such as a response time limit.

Question 8

What is the difference between static testing and dynamic testing?

Accepted Answer

Static testing examines software artifacts such as requirements, designs, and source code without executing the program. Dynamic testing runs the software and observes its behavior with specific inputs. Static testing can find defects early and in parts that dynamic tests rarely reach, while dynamic testing reveals problems that appear only during execution.

Question 9

What are the four common levels of testing, from smallest to largest scope?

Accepted Answer

The common levels are unit testing, integration testing, system testing, and acceptance testing. Unit testing checks individual components in isolation. Integration testing checks that components work together through their interfaces. System testing evaluates the complete integrated product against its requirements, and acceptance testing confirms the product meets the needs of users or customers.

Question 10

What is regression testing, and when should it be performed?

Accepted Answer

Regression testing is the repeated execution of existing tests to confirm that recent changes have not broken functionality that previously worked. It is performed after code changes, bug fixes, or configuration updates, and automation makes it fast to repeat. Good regression suites are kept focused on high-risk and frequently used areas.

Question 11

What is the difference between smoke testing and sanity testing?

Accepted Answer

Smoke testing is a broad, shallow set of checks run on a new build to confirm its core functions work well enough for deeper testing. Sanity testing is a narrow check after a specific change to confirm the problem is fixed and nothing obvious is broken nearby. Both are quick, but they serve different purposes in a test cycle.

Question 12

What is exploratory testing, and what makes it different from scripted testing?

Accepted Answer

Exploratory testing is an approach in which testers simultaneously learn about the product, design tests, and run them, using their experience to follow promising leads. Scripted testing follows predefined test cases written in advance. Exploratory testing is valuable for finding unexpected problems and for areas where documentation is thin.

Question 13

What is the difference between black box and white box testing?

Accepted Answer

Black box testing evaluates software from the outside by providing inputs and checking outputs against expected behavior, without looking at internal code. White box testing examines the internal structure, such as statements, branches, and logic paths, and designs tests to exercise them. Gray box testing combines both views.

Question 14

What is performance testing, and what kinds of questions does it answer?

Accepted Answer

Performance testing measures how software behaves under expected and heavy workloads, including its response times, throughput, resource use, and stability. It answers questions such as whether pages load within an agreed time and how many users the system can support. Load testing, stress testing, and endurance testing are common forms of it.

Question 15

What is usability testing, and how does it differ from functional testing?

Accepted Answer

Usability testing observes how representative users attempt realistic tasks with the software, noting where they struggle, hesitate, or make errors. Functional testing asks whether the software performs its specified behaviors correctly. A feature can pass every functional check and still be confusing, so usability testing gives insight that functional results cannot provide.

Question 16

What is security testing, and what kinds of weaknesses does it look for?

Accepted Answer

Security testing looks for weaknesses that could let unauthorized people read, change, or disrupt a system or its data. Typical targets include authentication and authorization flaws, improper handling of user input that enables injection attacks, exposed sensitive data, and insecure configuration. Specialists often combine automated scanning with manual testing.

Question 17

What is equivalence partitioning, and why is it useful?

Accepted Answer

Equivalence partitioning divides the possible inputs into groups that the software should treat the same way, then tests one representative value from each group. It is useful because it reduces an impossibly large number of inputs to a manageable set while still covering each distinct behavior. Invalid input classes should be tested separately from valid ones.

Question 18

How does boundary value analysis help testers find errors?

Accepted Answer

Boundary value analysis focuses on values at the edges of input ranges, because many programming mistakes occur at limits. For a field that accepts ages from 18 to 65, testers would check 17, 18, 19, 64, 65, and 66. Testing values just inside and outside each boundary exposes off-by-one errors that random values miss.

Question 19

What is decision table testing, and when is it most helpful?

Accepted Answer

Decision table testing lists combinations of conditions and the actions that result from each combination, arranging them in a table. It is most helpful when business logic depends on several interacting conditions, such as discount rules. Each column in the table becomes one test case, which makes gaps and contradictions easier to spot.

Question 20

What is state transition testing, and what does it reveal?

Accepted Answer

State transition testing models software as a set of states, the events that cause transitions between them, and the actions that occur during each transition. It is used for systems whose behavior depends on their history. Tests cover valid transitions and check that invalid events are handled correctly in each state.

Question 21

What is pairwise testing, and why does it reduce the number of tests needed?

Accepted Answer

Pairwise testing selects test cases so that every combination of values for any two parameters appears in at least one test. Many faults are triggered by interactions between just two parameters, so covering all pairs finds a large share of them with far fewer tests than every full combination requires.

Question 22

How do testers use error guessing as a test design technique?

Accepted Answer

Error guessing is a technique in which testers use their experience and intuition to predict where defects are likely to hide, then design tests aimed at those spots. Common targets include empty inputs, very long strings, special characters, duplicate submissions, and unusual sequences of actions. Error guessing works best alongside systematic techniques.

Question 23

What should a well-written test case include to be useful?

Accepted Answer

A well-written test case has a unique identifier, a clear purpose, preconditions that describe the required starting state, the exact steps to perform, the test data, and the expected result. Including the expected result is essential, because without it the tester cannot judge whether the software behaved correctly.

Question 24

What is path testing, and how does cyclomatic complexity relate to it?

Accepted Answer

Path testing designs tests to exercise independent paths through a program's control flow. Cyclomatic complexity is a metric that counts the number of linearly independent paths in a function, which gives the size of a basis set of paths to test.

Question 25

What information should a good defect report contain?

Accepted Answer

A good defect report includes a clear summary, the exact steps to reproduce the problem, the expected and actual results, the environment and build version, and any logs, screenshots, or data that help. It should describe one defect only and avoid guesses about the cause. Clear Reports save developers time.

Question 26

What is the defect life cycle, and what are its typical stages?

Accepted Answer

The defect life cycle describes the path a defect takes from discovery to closure. Typical stages include new or open when first logged, assigned to a developer, fixed or resolved after a change, ready for retest, verified or closed once a tester confirms the fix, and reopened if the problem persists.

Question 27

What is defect severity, and how does it differ from defect priority?

Accepted Answer

Severity describes how seriously a defect affects the system or its users, such as a crash that causes data loss versus a misspelled label. Priority describes how urgently the defect should be fixed. A low-severity defect can have high priority if it appears on the login page of a major launch.

Question 28

Which metrics are commonly used to track testing progress?

Accepted Answer

Common testing progress metrics include the number of test cases planned, executed, passed, and failed, along with the percentage of requirements covered by tests. Teams also track open and closed defects over time. These measures show how far testing has advanced, but they describe activity rather than the real quality of the product.

Question 29

What is defect density, and how is it calculated?

Accepted Answer

Defect density is the number of confirmed defects found in a software component or release divided by its size, commonly measured per thousand lines of code or per function point. Density helps compare modules, but it should be interpreted with care because size and testing effort vary.

Question 30

What is root cause analysis, and why is it valuable for teams?

Accepted Answer

Root cause analysis is a structured investigation that looks beyond the visible symptom of a defect to find the underlying process, design, or human factor that allowed it to occur. Its value lies in preventing whole categories of future defects, not just fixing one instance, which improves quality over time.

Question 31

How should a team handle a defect that cannot be reproduced?

Accepted Answer

Record every known detail, including environment, data, timing, and exact actions, since intermittent problems often depend on easily overlooked conditions. Then check logs and try variations of the steps. If the defect still cannot be reproduced, document the attempts and keep it open rather than closing it without explanation.

Question 32

What is the purpose of a traceability matrix in testing?

Accepted Answer

A traceability matrix links each requirement to the test cases that verify it. Its main purpose is to show coverage, so managers can see whether every requirement has been tested and which requirements are at risk. It also helps teams assess the impact of a requirement change by showing which tests must be updated.

Question 33

What is the purpose of continuous integration in quality assurance?

Accepted Answer

Continuous integration merges developers' code changes into a shared branch frequently and automatically builds the software and runs tests after each change. Its purpose in quality assurance is to catch integration problems and regressions within minutes or hours rather than weeks, when they are cheaper to diagnose and fix.

Question 34

What is test automation, and what kinds of tests are best suited to it?

Accepted Answer

Test automation uses scripts and tools to execute tests, compare actual results with expected results, and report outcomes without manual effort. Tests that are repeated often, stable, and based on clear expected results are usually the best candidates. Exploratory and usability tests, which depend on human judgment, are generally better performed manually.

Question 35

What is a test pyramid, and why is it used as a guideline?

Accepted Answer

The test pyramid is a model suggesting that a healthy suite has many fast unit tests at the base, fewer integration tests in the middle, and few slow end-to-end tests at the top. It is used as a guideline because lower-level tests run faster, are more stable, and make failures easier to diagnose.

Question 36

What is the purpose of a retrospective in an agile or iterative process?

Accepted Answer

A retrospective is a team meeting at the end of an iteration to review what went well, what did not, and what to change. It helps examine escaped defects, flaky tests, and unclear acceptance criteria. Improvement actions should be specific and checked at the next retrospective, so lessons lead to better quality.

Question 37

What is a quality gate, and how do teams use one?

Accepted Answer

A quality gate is a checkpoint in the delivery pipeline with defined criteria that must be met before work can move to the next stage. Criteria might include passing automated tests and having no open critical defects. If criteria are not met, the change is blocked or sent back for correction.

Question 38

How does risk-based testing help a team decide what to test first?

Accepted Answer

Risk-based testing ranks features and components by the likelihood of failure and the impact a failure would have on users or the business. Testing effort is then concentrated on the highest-risk areas, while lower-risk areas receive lighter coverage. This approach is especially useful when time or budget is limited, because it makes trade-offs explicit.

Question 39

Why should automated tests be kept maintainable, and what makes them fragile?

Accepted Answer

Automated tests are code and need the same care as production software, because unreliable tests slow delivery. Fragile tests often depend on timing, shared test data, unstable user interface locators, or hidden dependencies on other tests. Keeping tests independent, isolating external services, and removing flaky tests regularly helps the suite stay reliable.

Question 40

How does quality assurance contribute to long-term team success beyond finding bugs?

Accepted Answer

Quality assurance contributes to long-term success by building habits that prevent defects, such as clear requirements, reviews, and automated checks. When teams learn from defects and adjust their process, they spend less time firefighting and more time delivering value. Quality becomes a shared responsibility across roles rather than a final phase performed by a separate group.

Software Quality Assurance Flashcards

1Foundations of software quality assurance

2Testing levels and types

3Test design techniques

4Defects, traceability, and metrics

5Process improvement and automation

Learning Resources