Paper 1 Validation Testing Answers

These answers correspond to Paper 1 Validation Testing Drills.

Answer 1: Validation vs Verification

• Checking that the email contains @ and . is validation, because it checks whether the entry satisfies the form’s stated format rule.
• Asking for the email twice and comparing the entries is verification, because it checks whether the data was entered accurately.

The simple @ and . rule does not prove that the address is correct, deliverable, or intended.

Mark points:

• identifies the format-style email check as validation;
• identifies the double-entry match as verification.

Common weak answer:

• saying both checks are validation. Matching a repeated entry is verification, not a reasonableness check.

Answer 2: Range Check

The accepting condition is:

mark >= 0 and mark <= 100

Equivalent forms such as 0 <= mark <= 100 are also correct.

Mark point:

• accepts both endpoints 0 and 100 while rejecting values outside the range.

This answer is correct under the question’s assumption that mark is already an integer.

Common weak answer:

• using mark > 0 and mark < 100, which rejects valid boundary marks.

Answer 3: Format Check

Code	Valid?
AB1234	valid
A12345	invalid
Ab1234	invalid
CD12E4	invalid

Reasons:

• AB1234 has two uppercase letters followed by four digits;
• A12345 does not have two initial letters;
• Ab1234 has a lowercase second letter;
• CD12E4 has a letter in the digit section.

Mark points:

• correct judgement for each code.

Common weak answer:

• checking only the length. Length alone does not prove the character pattern is correct.

Answer 4: Presence Check

The value " " should be rejected because it contains only spaces. After removing surrounding whitespace, it is blank, so no actual student ID has been supplied.

Mark points:

• presence check ensures a required field is not blank;
• spaces-only input should be treated as blank.

Common weak answer:

• accepting the value because its length is greater than zero.

Answer 5: Check Digit

For 2462:

2 + 4 + 6 = 12
12 modulo 10 = 2

The check digit is valid.

For 2463, the expected check digit is still 2, but the supplied final digit is 3, so it is invalid.

Limitation: a check digit can detect some transcription errors, but it does not prove that the code belongs to a real record or that all possible errors are detected.

Mark points:

• correct calculation for 2462;
• correct rejection of 2463;
• states a valid limitation.

Common weak answer:

• saying a check digit corrects all data-entry errors. It usually detects some errors; it does not guarantee correction.

Answer 6: Test Data Types

One valid set:

Type	Values
normal	15
extreme	13, 18
abnormal	12, 19

Mark points:

• gives a normal value inside the range but not at a boundary;
• gives the lower boundary;
• gives the upper boundary;
• gives an abnormal value below range;
• gives an abnormal value above range.

Common weak answer:

• calling 13 abnormal. It is valid extreme data because it is on the boundary.

Answer 7: Error Type

Code or behaviour	Error type
if mark >= 50 print(“Pass”)	syntax
average = total / count crashes when count is 0	runtime
if mark > 50 gives "Fail" for mark = 50, although 50 should pass	logic

Mark points:

• syntax error for invalid Python grammar, specifically the missing colon after the condition;
• runtime error for division by zero during execution;
• logic error for code that runs but gives the wrong result.

Common weak answer:

• calling every wrong output a runtime error. A runtime error usually interrupts execution.

Answer 8: Debugging Trace

Trace:

Iteration	n	total after assignment
1	1	1
2	2	2
3	3	3

The logic error is that total = n replaces the previous total each time. It should accumulate:

total = total + n

The equivalent correction total += n is also valid.

Mark points:

• correct trace for first iteration;
• correct trace for second iteration;
• correct trace for third iteration;
• identifies replacement instead of accumulation.

Common weak answer:

• saying the loop runs only once. The trace shows the loop runs three times.

Answer 9: Test Plan

One valid test plan:

Test type	Input	Expected result
normal valid	50	True
extreme: lower boundary	0	True
extreme: upper boundary	100	True
abnormal	101	False

Mark points:

• includes one normal valid case;
• includes lower extreme value with expected result;
• includes upper extreme value with expected result;
• includes abnormal case with expected result.

Common weak answer:

• listing inputs without expected results. A test plan must say what should happen.

Answer 10: Predictable Runtime Error

For text = "abc", the conversion raises a runtime error because the program is executing but the value cannot be converted to an integer.

The specific exception to catch is ValueError.

A broad bare except is less helpful because it can hide unrelated faults. Catching ValueError makes the intended error handling clear.

Mark points:

• identifies the error as a runtime error;
• states ValueError;
• explains that catching a specific exception avoids hiding unrelated errors.

Common weak answer:

• using a bare except for all errors, which can make debugging harder.