Selecting & Using Suitable Test Data

When testing a program, test data is the input provided to check how the system behaves. To ensure that the program works correctly and handles different types of inputs, it's important to use a variety of test data.

Types of Test Data

Normal/Valid Data

Data that represents typical, expected input values.
It should be accepted by the program without causing errors.
Example: For a range between 1-10, 5 is normal test data.

Boundary Test Data

Data that is on the edge of being valid but still within the acceptable range.
Used to ensure the program can handle values at the upper or lower limits.
Example: For a range between 1-10, 1 and 10 are boundary values.

Invalid Data

Data that is the correct type but falls outside the valid range.
The program should reject this data.
Example: For a range between 1-10, 0 or 11 would be invalid.

Erroneous Data

Data that is the wrong type or completely unexpected (e.g., letters instead of numbers).
The program should reject such data.
Example: Entering A when the program expects a number.

Test Plan

A test plan outlines the approach for testing a program, including what will be tested, the test data used, and the expected result. This ensures all possible input cases are covered and helps identify any issues in the program.

Key Components of a Test Plan

Purpose of the test: What are you testing (e.g., input validation, functionality)?
Test data: The values you will input during the test.
Expected result: What the program should do in response to the test data.

Example Test Plan for Input Validation

Test No	What is Being Tested	Test Data	Expected Result
1	Normal values inside the range are accepted	5 (Valid)	Value is accepted
2	Values outside the range are rejected	12 (Invalid)	Value is rejected
3	The last value in the range is accepted	10 (Boundary)	Value is accepted
4	Values just outside the range are rejected	11 (Invalid)	Value is rejected
5	Data of the wrong type is rejected	A (Erroneous)	Value is rejected

infoNote

Key Points for Effective Testing

Normal test data ensures the program functions correctly with the expected input.
Boundary test data checks how the program handles the limits of the acceptable range.
Invalid and erroneous data test whether the program can correctly reject unsuitable inputs.

Selecting & Using Suitable Test Data Simplified Revision Notes for GCSE OCR Computer Science