Testing: Computer Science OCR: GCSE (9:1)

Syntax error

An error because the rules of the language have been broken, such as forgetting a bracket or mis-spelling a keyword

Logic error

An error that occurs when code runs but produces unexpected results. E.g. adding instead of subtracting or stopping a loop too soon. It is detected by systematic testing with a trace table

Test plan

A structured plan for testing a program. Includes test data and expected results. Using one can find logic errors and prevent runtime errors

Trace table

All the values of variables at each specific point during execution, written down in a table. It proves the code meets requirements and finds logic errors.

Test data

Data used as input to test a program. It should test all conditions in the code thus forcing all conditional code to execute. Can be valid, boundary and invalid.

Normal

Test data that is expected e.g. the code

if age < 18 then

might be tested with data of 14

Boundary

Extreme test data at the edges of the valid range. Phone battery percentage must be between 0 and 100, so these test data values would be 0 and 100

Invalid

Data with the correct type but not in the expected range. For example a validation routine using:

while angle > 360

could be tested with data of 361 or 425

Erroneous

Data of the wrong type. For example if we are expecting a number, we should test the program with string input. The program should reject this but not fail

Dry Run

A walk through of the code "on paper" i.e. without running it, to check it meets requirements and identify logic errors

Iterative

Testing a program repeatedly while it is still being developed. The programmer writes a section of code or module then tests and fixes it, then does that again

Final

Also called terminal, this testing is carried out when all modules are complete. The program is tested as a whole to ensure that it functions as it should