COMPSCI130 Chap.2 Maintenance, Modularity, Testing and Exceptions

Maintenance, Modularity, Testing and Exceptions

Define module

The course material gives this chapter a concrete anchor: Official Topic 2 combines maintenance, modularity, testing and exceptions as one software-quality cluster. That module anchor controls how test case is explained and how exception is tested in changed practice.

Maintenance, Modularity, Testing and Exceptions turns module, test case and exception into executable reasoning.

The chapter's practical target is to refactor a fragile function into testable components and design normal, boundary and failure-path checks, so every explanation should connect syntax to program state, control flow and observable output.

Treat module as a precise program object, not a loose label. Identify the value or responsibility of module before execution, then trace what can read it, change it or depend on it.

This makes state changes visible before they become debugging guesses.

Use test case to explain the program's next move. Work through one representative test case input by hand and name the branch, iteration or call that follows.

If the test case trace cannot be stated, the code may run by accident rather than by understood design.

Trace test case

Bring in exception as the test of structure.

Compare normal, boundary and invalid inputs for exception; state the expected behaviour first; then use the mismatch between expectation and result to localise the defect.

For the application — refactor a fragile function into testable components and design normal, boundary and failure-path checks — write the smallest complete example that exposes the rule.

Explain why the exception result works, what would break it and how the program should signal or recover from that failure.

Before running an module example, make a trace table with the important state before and after each operation. Include the value associated with module, the control decision governed by test case and the output or object affected by exception.

The module table turns an unexplained result into a sequence that can be tested one transition at a time.

Test three inputs: an ordinary case, a boundary case and an invalid case. State the expected exception result for each before execution, then compare it with what the program actually does.

A useful test of test case isolates one rule; changing several conditions at once cannot reveal which condition caused the failure.

Test with exception

Practise explaining the solution without reading the code.

For COMPSCI130, name the data representation, the control flow, the responsibility of each function or class and the reason the chosen design supports refactor a fragile function into testable components and design normal, boundary and failure-path checks.

This exception rehearsal matters when a written test or interview asks why the program works rather than whether it produces one correct output.

A complete response should make the task visible before the detail: identify what must be decided, define the relevant terms, connect the evidence to test case, and use exception to test the result.

The final sentence about exception should answer the question actually asked rather than merely repeat the topic.

The controlling limit is specific: Passing selected tests demonstrates those observed behaviours but cannot prove the absence of all defects or justify swallowing unexpected exceptions.

Keep that exception limit beside the worked example, because it separates a careful COMPSCI130 answer from one that sounds confident but claims more than the task or evidence supports.

For revision, retrieve module, test case and exception without notes, explain their relationship aloud, then complete a changed version of the application: refactor a fragile function into testable components and design normal, boundary and failure-path checks.

Record the first failed test case reasoning move and repair it before attempting another case.

What this chapter covers

• 01

  module

• 02

  test case

• 03

  exception

• 04

  Applying module

• 05

  Limits of test case and exception

AskSia practice: apply Maintenance, Modularity, Testing and Exceptions

Key terms

module

A separately named program unit that groups related definitions behind a deliberate interface. Use this definition when the task is to refactor a fragile function into testable components and design normal, boundary and failure-path checks.

test case

A specified input, expected behaviour and observation used to check one aspect of a program. Use this definition when the task is to refactor a fragile function into testable components and design normal, boundary and failure-path checks.

exception

A runtime event that interrupts ordinary control flow and can be propagated or handled explicitly. Use this definition when the task is to refactor a fragile function into testable components and design normal, boundary and failure-path checks.

Maintenance, Modularity, Testing and Exceptions FAQ

Exam move

Reconstruct the relationship among module, test case and exception; complete the chapter application without notes; then test the result against this limit: Passing selected tests demonstrates those observed behaviours but cannot prove the absence of all defects or justify swallowing unexpected exceptions.

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