chapter 4 Flashcards
What is The purpose of a test design technique
to identify test condition, test case, and test data
Why is A testing Technique important?
Effective
- Find more faults
- Focus attention on specific types of faults
- Know you are testing the right thing
Efficient
- Find faults with less efforts
- Avoid duplication
- Systematic techniques are measurable
What are the Categories of Test Design Techniques
- Specification-based
- Structure-based
- Experience based
… is Specification-based while … is Structure-based
Black Box , White Box
What are the Advantages of black-box testing
- focus on the functional behavior
- Independent from the internal code
- Can catch logic defects early
- Applicable at all levels of granularity
- allows for early test design
What are the Black-box testing process
Analyze requirements
Choose valid and invalid inputs
Determine expected outputs for those inputs
List the Black box testing techniques
Equivalence Partitioning
Boundary Value Analysis
Decision tables testing
State transition testing
Use case testing
What is Equivalence Partitioning (EP)
is a black-box testing technique that divides the input domain of a software system into different equivalence classes or partitions.
EP divides the possible inputs into groups called …
equivalence classes.
The rule for EP is to select one representative value from each equivalence class as a test case.
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This ensures that each class is adequately tested, covering both valid and invalid inputs.
In EC, The partitioning is based on …
requirements of the software system
What is Challenging for the tester when using EC Testing?
- Different testers find different equivalence classes
- Finding an appropriate partition not knowing how the program looks inside.
How does Ep test invalid inputs
- For invalid equivalence classes, boundary values are often tested to ensure the system behaves as expected.
… is used only for valid inputs
Testing by contract
… and … weaken the need to
use defensive testing
- GUIs &
- Strong typed programming languages
how do GUIs and strong typed programming languages weaken the need to use defensive testing
- GUI elements often enforce certain constraints on user input and can prevent users from entering invalid data.
- GUI frameworks include built-in validation mechanisms
- Strongly typed programming languages enforce strict type checking at compile-time
- So they type-related errors before runtime
Given this Req : Age field can take the values in the range of 20 to 50. What is the best EP approach to test it?
Include these partitions :
- Below range - 10
- Within Range 20 to 50 - 40
- Above range - 60
- Whole numbers - 40
- Real numbers - 30.4
- Numbers - 40
- Characters - xyz
- +ve numbers - 40
- -ve numbers - -30
- 0-0
What is Failure Masking in Equivalence Partitioning
Failures can be masked when several failures occur at the same time but only one is visible, causing the other failures to undetected
What must be done To achieve 100% coverage with Equivalence Partitioning?
Test cases must cover all identified partitions (including invalid partitions) by using a minimum of one value from each partition
How do we calculate Equivalence Partitioning Coverage %
Total Number of Tested EP
/
Total Number of EP
How does Equivalence Partitioning work with Discrete Values?
- equivalence classes are formed based on the distinct values
Example : if a field accepts colors as input, the equivalence classes could be “Red,” “Blue,” “Green,” etc.
How does Equivalence Partitioning Multiple Conditions work given :
Age : (< 20),(20 >= and <=50), ( >50)
Country: (Egypt), (Canada), (USA), (India)
3 partitions + 4 partitions = 7 Partitions
Test cases
TC1:(10,Egypt)
TC2: (40,Canda)
TC3:(60,USA)
TC4:(45,India)
How did Boundary values testing (BV) come about?
a surprising nr. of faults turned out to be boundary value faults
BVT is most applicable when …
- inputs are constrained and fall within certain minimum and maximum limits.
- For boolean values has no sense.
BVT focuses on the boundary of the…
input domain
If x is an input variable with values in the range [xmin,xmax] then test the system is:
- xmin
- just above xmin
- a nominal value, xnom
- just below xmax
- xmax
Explain The “single fault assumption”.
is a principle used in black-box testing. It posits that a failure in the system is caused by only one fault at a time.
how does The “single fault assumption” work?
- Hold all but one variable at nominal values: In this approach, all input variables except one are kept at their nominal or typical values.
- Let only one variable take extreme values: One input variable is manipulated to take on extreme or boundary values.
What are Boundary Value Extensions
These are additional strategies or techniques applied to Boundary Value Testing to increase its effectiveness.
Give types of Boundary Value Extensions
- Robustness testing
- Worst case testing
- Robust worst case testing
- Special value testing
- Random testing
… aims to evaluate the ability of the software system to handle invalid or unexpected inputs.
- Robustness testing
subjecting the system to inputs that lie outside the normal operating range
… involves testing the system under conditions that represent the most unfavorable or extreme scenarios.
Worst case testing
… involves selecting specific input values that are known to trigger certain behaviors or edge cases within the system.
Special value testing
explain Decision Table Testing
is a black-box testing technique used to test systems where the output depends on multiple input conditions or combinations of conditions.
What is The state transition technique
is a black-box testing approach, suitable for systems where the response varies depending on the current state or previous history of the system.
Requirements for Calculating Car Insurance Premiums:
- For female between 18 and 64 years of age, the premium is 500
- For males between 18 and 64 year of age, the premium is 1000
- For anyone 65 years of age or more, the premium is 1500
- Anyone less than 18 years of age, can’t get insurance
What is the minimum number of test cases needed to test this requirements?
Gender: Female, Male
Age :18 <= Age <= 64, Age >= 65, Age < 18
Total combinations = 2 (Gender) * 3 (Age) = 6 combinations
So, for Age < 18, the output is not applicable (N/A), and there’s no need to test it further.
-> the minimum number of test cases needed is 5
explain State Transition Diagram
- This diagram visually represents the various states that the system can be in and the transitions between these states.
- State = node
- Transitions between states = arrows
A transition is initiated by …
an event
The system may behave differently to the same trigger or transition according to its current state.
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What is a State Transition Table
A state table records all the possible valid or invalid transitions, guard conditions and their effect on all the possible states.
Explain Use Case Testing
it is a black-box testing technique that focuses on deriving test cases from use cases
… are very useful for designing acceptance tests with user participation
use cases
… is an excellent basis for system level testing
use case
Explain use cases
- describe interactions between actors and the system
Test cases derived from use cases are most useful in …
uncovering defects in the process flows during real-world use of the system
A use case usually has … components?
- a most likely scenario
- alternative paths
- preconditions
- postconditions and
- final state of the system
White Box Testing, is also known as …
structural testing or glass-box testing,
White Box Testing derives test cases from …
the internal structure or code of the system being tested.
Coverage of White box testing is measured based on …
the items tested within a selected structure(e.g the code or interfaces)
In white box testing … are used as an additional source of information to determine the expected outcome of test cases.
Specifications
… are used to assess the amount of testing performed by tests derived from black-box techniques.
White Box Testing techniques
How do we determine Statement coverage in WBT
the number of executable statements covered by test cases
/
the number of all executables statements in the code
