What is Software Testing?

Question 1

What is Testing?

Answer 1

Evaluating software in order to derive an estimate as to whether or not it meets some criteria.

Question 2

What can testing do?

Answer 2

It can build confidence that key properties hold.

Question 3

Dynamic Testing

Answer 3

Form of testing that involves executing the code.

Question 4

Static Analysis

Answer 4

Form of testing which does not involve executing the code.

Question 5

What are some forms of Static Analysis?

Answer 5

• Inspections
• Walkthroughs
• Syntax Check (Linter)

Question 6

What are some forms of Dynamic Testing?

Answer 6

White box, grey Box, Black box, functional testing, Non-functional testing…

Question 7

Grey-box testing and why you may use it?

Answer 7

Involves prior knowledge about the system to compose tests.

• Building tests for many implementations of a product.
• Closed-source product

Question 8

Black-box testing

Answer 8

Involves testing a product without any knowledge of its implementation, only its requirements.

Question 9

White-box testing

Answer 9

Involves testing that exploits full knowledge of the system and source code.

Ex: following branches

Question 10

What is an example of a Black/Grey/White box test for an Apache Web-server

Answer 10

B: Run external request generator.
G: Run generator with prior knowledge of most taxing requests (bottlenecks).
W: Run generator with code coverage to see which parts of the code are run

Question 11

Functional Testing

Answer 11

Involves testing the product to ensure it provides a particular functionality.

Question 12

Non-functional Testing

Answer 12

Involves testing the product on something other than whether it provides some function.

Question 13

What is an example of a Functional and Non-functional test for a smartphone app

Answer 13

F: Does our app link to Facebook?
NF: Does the app divulge personal information?

Question 14

Define a Fault and give an example of one

Answer 14

A property that can cause a failure to occur in a program. It is still stable.

Ex: A for loop starts at the wrong index and thus misses that index when the expected behaviour is to check it.

Question 15

Define an Error and give an example of one.

Answer 15

A bad state of a running program which may lead to a failure.

Ex: A variable that checks how many multiples of two appears in an array is modified unexpectedly.

Question 16

Define a Failure and give an example of one.

Answer 16

The software does something observably bad.

Ex: A unit test case in JUnit fails.

An Exception is triggered such as arrayOutOfBounds.

Question 17

Name the strengths of unit testing

Answer 17

Can pinpoint a low-level fault precisely.

Can be easily conducted individually by the actual programmer (more knowledge of the system)

Question 18

What is a limitation to unit testing

Answer 18

Many faults do not manifest at the unit level (method or class), they manifest in the interactions within the system.

Question 19

What is System testing

Answer 19

Testing that involves the entire system as a whole (typically blackbox)

Question 20

Name the strengths of System testing

Answer 20

• Can find faults in your design
• Tests both functional and Non-functional requirements.
• Can help understand non-explicit requirements (Behaviour that “seems” wrong)
• Can pass on this task to a specialist team that is familiar with this testing.

Ex: Ariane 5 launch system simulation, would have found fault.

Question 21

Limitations of system testing

Answer 21

Some part interacting faults are still difficult to find at system level

Question 22

Integration testing

Answer 22

Testing interacting classes, modules or subsystems.

Taking a bunch of units and testing together at that level in blackbox style.

Question 23

What are the main approaches of integration testing

Answer 23

Big Bang: Put everything together and test.
Top-down: Modules tested from entry points and integrated progressively.
Bottom-up: Modules progressively integrated and tested from the most elementary ones.

Question 24

Name the strengths of integration testing

Answer 24

• More traceable than system test

- tests the interactions that unit testing cannot

Question 25

How can we convince someone that our tests are sufficient

Answer 25

Acceptance testing. Not to really discover failing scenarios. To ensure for the customer that the product works for their need.

Ensuring the system is in harmony with the environment it is intended for.

Question 26

Strengths of Acceptance testing

Answer 26

A VALIDATION activity. Did the right product get built.
Helps build trust with customer.
Understand the customer, domain and market.

Question 27

What is a form of testing that is done repetitively over the life of a system

Answer 27

Regression testing. Automated tests are formed into a testing suite for further versions.