Paper 2 Robustness

Question 1

What is meant by the term ‘Validation’?

Answer 1

Validation is an automatic check to ensure that data entered is sensible and feasible.

Question 2

State 3 methods of writing maintainable code.

Answer 2

comments
descriptive names for variables, constants and subprograms
indentation

Question 3

Explain the differences between input sanitation and input validation

Answer 3

Validation checks if the input meets a set of criteria (such as input being a string). Sanitization modifies the input to ensure that it is valid (such as forcing input to be Uppercase)

Question 4

What is meant by the term ‘Iterative Testing’?

Answer 4

Iterative testing is carried out while a program is being developed. The programmer writes a section of code (module) then tests it. The module may work fine, but more likely the programmer will amend or fix the code, and test it again. The process repeats (iterates) until the module works as intended.

Question 5

What is a ‘Syntax’ error?

Answer 5

A syntax error is an error where you have broken the syntax rules of the programming language such that the compiler or interpreter is not able to understand what you meant to take place, and thus it has to stop compiling your program (or in an interpreted language, stop execution.)

Question 6

What is a ‘Logic’ error?

Answer 6

Logic errors occur when there is a fault in the logic or structure of the problem. For example parts of a program may:

• be in the wrong sequence
• have the wrong Boolean expression
• use the wrong data type
• be missing altogether

Question 7

What is a ‘Run-Time’ error?

Answer 7

A runtime error occurs when a program is syntactically correct but contains an issue that is only detected during program execution.

Question 8

What is meant by the term ‘Acceptance Testing’?

Answer 8

Acceptance Testing is a level of software testing where a system is tested for acceptability. The purpose of this test is to evaluate the system’s compliance with the business requirements and assess whether it is acceptable.

Question 9

Explain the need for comments to be used during programming.

Answer 9

Commenting involves placing Human Readable Descriptions inside of computer programs detailing what the Code is doing. Proper use of commenting can make code maintenance much easier, as well as helping make finding bugs faster. Further, commenting is very important when writing functions that other people will use. Remember, well documented code is as important as correctly working code.

Question 10

Identify different types of authentication that can be used by computer systems.

Answer 10

Password-based authentication. 
Multi-factor authentication. 
Certificate-based authentication. 
Biometric authentication.
Token-based authentication.

Question 11

What do we mean by the term “Normal testing”?

Answer 11

Sensible, possible data that the program should accept and be able to process

Question 12

What do we mean by the term “Extreme testing”?

Answer 12

Extreme values are used in testing to make sure that all normal values will be accepted and processed correctly. e.g.
In a system that was designed to accept and process test marks (percentages), then extreme test values would be: 0 (lowest possible value) 100 (highest possible value)

Question 13

What do we mean by the term “Erroneous testing”?

Answer 13

Data that the program cannot process and should not accept. e.g.
In a system that was designed to accept and process test marks (percentages), then test values : -100 or 1000 should NOT be accepted.