Test data and errors

What this lesson covers

• Suggest and apply normal, abnormal, extreme and boundary test data
• Identify errors in algorithms and suggest corrections

Key vocabulary

Test data

Data chosen to test whether a program works.

Normal data

Sensible data that should be accepted.

Abnormal data

Data that should be rejected: out of range or the wrong type.

Extreme data

The largest or smallest acceptable value.

Boundary data

The largest or smallest acceptable value, and the value just beyond it that should be rejected.

Test plan

A list of tests, with test data, type and expected result.

Syntax error

Code that breaks the grammar rules of the language, so it can't be translated.

Logic error

The program runs but does the wrong thing.

Runtime error

An error while the program runs that makes it crash, such as dividing by zero.

Check your learning

• Quick check: 4 questions
• Key vocabulary test: 9 terms
• Activity 1: Which test data? · 7 questions
• Activity 2: Which type of error? · 6 questions
• Activity 3: Spot the error · 5 questions
• Activity 4: Testing quiz · 8 questions