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Testing an Object Oriented Application

Choosing test data: normal, boundary and erroneous

  • 3 things to know
  • AS Unit 1

Overview

Test data, equivalence partition and testing with an empty value.

What you need to know

Answer each one before you reveal it.

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Key term

What is test data?

Key term

What is normal test data?

Key term

What is erroneous test data?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    What is test data?

    Model answer

    Test data is the set of values deliberately chosen to be fed to a program during testing, each one paired with the result it should produce, written down before the test is run.

  2. 2

    What is normal test data?

    Model answer

    Normal test data is a value lying well inside the acceptable range, representing the everyday case the program is expected to handle.

  3. 3

    What is boundary test data?

    Model answer

    Boundary test data is a value sitting exactly at the edge of the acceptable range, or immediately either side of that edge, where off-by-one mistakes reveal themselves.

  4. 4

    What is erroneous test data?

    Model answer

    Erroneous test data is a value the program should reject, either because it falls outside the acceptable range or because it is of the wrong kind altogether.

  5. 5

    A method accepts an exam mark from 0 to 100. Give one normal, one boundary and one erroneous value.

    Model answer

    A normal value is 57, a boundary value is 100, and an erroneous value is 101 or a word typed where a number was expected.

  6. 6

    For a method accepting a mark from 0 to 100, which four values at the edges are worth testing?

    Model answer

    The values worth trying are −1 and 0 at the lower edge and 100 and 101 at the upper edge, because each pair straddles the point at which acceptance should change.

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Software and the Development Environment
Defining Data: Types, Variables and Classes
Program Control Structures
Objects, Classes and Data Structures

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