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Questions and Answers
What is Decision Testing?
A white box test design technique in which test cases are designed to execute decision outcomes.
Define Decision Coverage.
The percentage of decision outcomes that have been executed by a test suite.
What does Decision Coverage imply?
Decision coverage is a stronger criteria than statement coverage.
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What is the purpose of statement coverage in testing?
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How is statement coverage calculated?
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How is a test case defined in statement coverage?
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What is the key criteria for a test to be viewed as completed in statement coverage?
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What is the weakness associated with statement coverage?
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What is the purpose of the while loop in the provided code snippet?
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Which variable gets assigned the remainder of 'm' divided by 'n'?
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Java uses && and || for bit-wise operations.
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Decision coverage considers exclusively the resulting truth value of a logical decision (true/false) to determine the ______ in the control flow graph.
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What is the primary focus of white-box test design techniques?
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Black-box tests are derived with knowledge of the program logic.
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Define 'White-Box Test Design Technique.'
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What is the primary purpose of white-box testing? Testing based on an analysis of the __________ of the component or system.
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Match the following criteria with their respective white-box testing techniques:
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What is the formula for calculating path coverage?
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Path coverage is more important as a theoretical measure than in practice. (True/False)
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What can be considered when deriving test cases from paths in software testing?
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Path: (1, 2-3, 4-6, 7, 8, 9-11, 8, 12, 13). For statement coverage, the logical (abstract) test case is: { ___ > ___ ∧ ___ % ___ ≠0 ∧ ___ % (___ % ) = 0 ; gcd(, ___) }
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What does the MC/DC coverage requested in DO-178B demand?
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What is the focus of the 'Linear Code Sequence and Jump' (LCSAJ) test design techniques?
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True or False: The 'Modified Condition/Decision Coverage' (MC/DC) requested in DO-178B is identical to the minimal multiple condition coverage.
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In source code, ___ means that conditions are only tested until the truth value has been determined.
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Match the following coverage criteria with their descriptions:
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What is the fundamental idea of experience-based test design techniques?
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Which of the following are examples of experience-based test design techniques? (Select all that apply)
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What is error guessing in the context of software testing?
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What is the purpose of the mutation test system as described in the text?
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Which of the following is not a mutation operation defined by the mutation test system in the text?
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Statement: All mutants are considered good if they have passed all test cases successfully.
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In white-box test design techniques, the test object must be _____________ at strategically important points before the test is executed.
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What does simple condition coverage require in terms of testing single conditions in decision statements?
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What is the formula for condition coverage?
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What does multiple condition coverage consider in addition to simple condition coverage?
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What is the purpose of Multiple Condition Coverage?
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Condition Determination Coverage tests the percentage of all single condition outcomes that independently affect a decision outcome that have been exercised by a test case suite. It implies 100% decision coverage if it achieves ____% Condition Determination Coverage.
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What is the formula for calculating Path Coverage?
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Why are statement coverage and decision coverage insufficient for object-oriented systems?
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In White-Box Testing, what is used to evaluate the completeness of the test according to the data use?
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Study Notes
Dynamic Testing - White-Box
- White-box testing is a type of software testing that involves analyzing the internal structure of a component or system to detect faults.
- It is also known as structure-based, structure-oriented, or structural testing.
Structure-Based Testing
- Control flow-based testing:
- Statement coverage (C0-coverage): all nodes of the control flow graph are executed.
- Decision coverage (C1-coverage): all edges of the control flow graph are executed.
- Boundary-interior coverage (Cgi): all loops are executed once, repeatedly, and rejected once.
- Path coverage (C∞-coverage): all possible paths of the control flow graph are executed.
- Data flow-based testing:
- All definitions (all defs): all definitions of variables are executed.
- All definition-use pairs (all def-uses): all pairs of definitions and uses of variables are executed.
- Condition-based testing:
- Simple condition coverage: all conditions are executed.
- Multiple condition coverage: all combinations of conditions are executed.
- Minimal multiple condition coverage: all minimal combinations of conditions are executed.
Experience-Based Testing
- Error guessing: testing based on the tester's experience and intuition about where errors might occur.
- Exploratory testing: testing that involves exploring the system's behavior without a preconceived notion of what might happen.
Choosing Test Design Techniques
- The choice of test design technique depends on the specific context and requirements of the system.
- Different techniques may be used for different parts of the system or for different testing phases.
White-Box Test Design Techniques
- Statement coverage: ensures that all statements in the code are executed.
- Decision coverage: ensures that all decisions in the code are executed.
- Condition coverage: ensures that all conditions in the code are executed.
- Path coverage: ensures that all possible paths of the code are executed.
- Mutation testing: involves modifying the code in small ways to see if the tests detect the changes.
- Data flow-based testing: ensures that all data flows through the code are executed.
Code Coverage
- Code coverage measures the percentage of the code that is executed during testing.
- It is used to evaluate the effectiveness of the testing.
Dynamic Test
- Dynamic test is a type of testing that involves executing the code to see how it behaves.
- It is used to evaluate the system's behavior under different conditions.
Black-Box vs. White-Box Testing
- Black-box testing: testing that involves only the input and output of the system, without knowledge of the internal structure.
- White-box testing: testing that involves analyzing the internal structure of the system to detect faults.
Test Design Techniques
- Test design techniques are used to derive and select test cases based on the analysis of the internal structure of the system.
- They are used to evaluate the completeness of the testing.
GCD Function
- The GCD (Greatest Common Divisor) function is an example of a function that can be tested using white-box testing.
- The function takes two integers as input and returns their greatest common divisor.
Control Flow Graph
- A control flow graph is a graphical representation of the flow of control through a program.
- It is used to visualize the structure of the program and to identify the different paths that the program can take.
UML/Java Specifications
- UML (Unified Modeling Language) is a language used to specify the behavior of systems.
- Java is a programming language used to implement the system.
- The specification of the GCD function in UML/Java is used to define the expected behavior of the function.### Control Flow-Based Coverage Criteria
- Statement coverage is a dynamic, control flow-based test design technique that requires all statements of the test object to be executed at least once.
- Formula: Statement coverage = (Statements executed / Total statements) * 100%
- Each test case is defined from a path of the control flow graph, and the edges of the graph that are on the path must be executed in the test case.
Example: Statement Coverage for gcd()
- Path: (1, 2-3, 4-6, 7, 8, 9-11, 8, 12, 13)
- gcd() function example is used to illustrate statement coverage.
Discussion about Statement Coverage
- Statement coverage is a relatively weak criteria.
- Empty edges have no meaning for statement coverage.
- 100% coverage of statements is not always reachable in practice.
- May indicate the presence of unreachable statements (dead code).
Decision Coverage
- Decision coverage is a white box test design technique that requires test cases to execute decision outcomes.
- Formula: Decision coverage = (Decision results executed / Total decisions) * 100%
- Each test case is determined by a path through the control flow graph to the decision being considered.
- Decision coverage is stronger than statement coverage.
Example: Decision Coverage for gcd()
- Path 1 = (1, 2-3, 4-6, 7, 8, 12, 13)
- Path 2 = (1, 2-3, 7, 8, 12, 13)
- Decision coverage is calculated based on the number of decision outcomes executed.
Discussion about Decision Coverage
- Decision coverage is a stronger criteria than statement coverage.
- Decision coverage can detect missing statements.
- 100% decision coverage implies 100% branch coverage and 100% statement coverage.
Addendum: Boundary-Interior Coverage
- Boundary-Interior coverage is a dynamic, control flow-based test design technique that requires each loop to be executed in at least three test cases.
- Not at all (only if loops deter, e.g., while- or for-loop for which abort condition is true at first evaluation)
- Exactly once
- More than once
- Formula: Boundary-Interior coverage = (Number of (gi)-tested loops executed / Total loops) * 100%
Addendum: Path Coverage
- Path coverage is a dynamic, control flow-based test design technique that requires each path in a control flow graph to be executed at least once.
- Formula: Path coverage = (Number of paths executed / Total paths) * 100%
- In practice, not reachable, more important as a theoretical measure.
Example: Path Coverage for gcd()
- Multiple paths are demonstrated for the gcd() function.
From Path to Test Case
- Previously, paths were determined through the control flow graph, which were to be executed by the test cases.
- Question: Which input values can enforce these paths?
- Idea: Consider the conditions of statements that determine control flow.
- Constraints for program variables can then be »computed«.
Test Case for Statement Coverage
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Logical (abstract) test case: { n > m ∧ n % m ≠0 ∧ n % (n % m) = 0 ; gcd(m, n) }
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Low-level (concrete) test case: { m = 4, n = 6; 2 }### Test Case for Decision Coverage
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Path: (1, 2-3, 7, 8, 12, 13)
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Logical (abstract) test case: {n ≤ m ∧ m % n = 0 ; gcd(m, n) }
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Low level (concrete) test case: { m = 4, n = 4; 4 }
Control Flow-Based and Object-Oriented Software
- Statement coverage and decision coverage are insufficient for object-oriented systems
- Complexity of object-oriented systems are often hidden in the correlations of classes or the interactions of objects
- Methods in the classes are usually less extensive and of less complexity (McCabe: 2-4)
- The required statement and/or decision coverage is then reachable with less effort
- Tool support for measuring coverage metrics is available for object-oriented systems
White-Box Techniques
- Exploratory testing, error guessing, experience-based testing, and evaluation of white-box techniques
- Power of white-box techniques, mutation testing, and concept of white-box techniques
- Further white-box test design techniques: mutation, LCSAJ, condition testing, data-flow-based testing
- Differences between black-box and white-box techniques, and evaluation of white-box techniques
Data Flow-Based Test
- Dynamic test in which the test cases are derived by considering the data used in the test object
- Completeness of the test (coverage) will be evaluated according to the data use
- Tests considering variable and data usage: value assignment, state change, use in expression, state preserving, and use in conditions
- Use in expression, state preserving: Definitional use, def (r), and computational use, c-use (m,n) and def (r)
Addendum: Data Flow-Based Coverage Criteria
- Hypothesis: defective data use!
- All-defs criteria: Use each definition at least once in one c-use or p-use without creating any new def in between
- Example: All-defs: 1, def m: p-use 3-4, 1, def n: p-use 3-4, ...
- Further criteria: All p-uses / All c-uses / All uses /...
Conditions in Programs (and Specifications)
- Truth values: false, true (often also 0, 1)
- Single (basic) condition: Type of variables boolean, operations with return value of type boolean, comparative operations
- Compounded condition: Linking partial conditions with boolean operators, basic-operators are and (∧, ∩), or (∨, ∪), not (¬ )
- Decisions often use compound conditions to control the program flow
- In Java: &, |, ^ Bit-wise and, or and exclusive-or-link, &&, || As above, but lazy evaluation
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Description
This quiz covers the learning objectives of the Certified Tester Foundation Level, specifically white-box test design techniques and structure-based testing. Understand the fundamental idea of white-box testing and characterise its design techniques.
