IGCSE Computer Science Paper 2 Definitions Worksheet: 7a Program Development Life Cycle (Modules 71–82)
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Key terms
Write what each term means, in your own words.
1
Normal test data
2
Abnormal test data
3
Extreme test data
4
Boundary test data
5
extreme vs boundary data
6
Range check test data
7
LENGTH(Password) >= 8
8
dry run
9
one column per variable
10
OUTPUT column
Answer Key
IGCSE Computer Science Paper 2 · Modules 71–82 · Student wording will vary for definitions
1Normal test data — A typical, valid value well inside the allowed limits, which the program should accept. Example: an age of 30 for a range check of 0 to 120 is accepted.
2Abnormal test data — Test data of the wrong type or outside the allowed values, such as -5 or letters for an age, or an empty input. The program should reject it.
3Extreme test data — The largest and smallest values a program should accept, such as 0 and 120 for a range of 0 to 120. They sit exactly on the limits and the expected outcome is accepted.
4Boundary test data — The largest and smallest acceptable values plus the nearest rejected values either side of each limit, e.g. 0 and -1, 120 and 121 for a range of 0 to 120.
5extreme vs boundary data — Extreme data is only the accepted limit values, e.g. 1 and 100. Boundary data has those plus the rejected values next to them: 0, 1, 100 and 101 for a range of 1 to 100.
6Range check test data — Pick one normal, abnormal, extreme and boundary value for the range and say accept or reject. For 0 to 100: 50 normal, -5 abnormal, 100 extreme, 101 boundary.
7LENGTH(Password) >= 8 — Test data for a check includes values that pass and fail it: for an 8-character minimum, 8 characters is accepted, 7 is rejected, and an empty string fails a presence check.
8dry run — Working through an algorithm by hand, line by line, using chosen test data as inputs and recording each step in a trace table, to see what it does and find logic errors without running it.
9one column per variable — To set up a trace table, give each variable its own column in the order they first appear, then add a row each time a value changes. Leave unchanged cells blank.
10OUTPUT column — The trace table column where you write each value or message shown by an OUTPUT statement, on the row where it happens. Text in quotes is copied exactly as the output.