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Testing and Evaluating the Solution

Testing validation and error handling

  • 3 things to know
  • A2 Unit 2

Overview

Confirming each rule refuses what it should and accepts what it should, that the message names the field and the problem, and that a refused entry leaves the user's data on screen.

What you need to know

Answer each one before you reveal it.

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Key term

Why is every validation rule given a test of its own?

Key term

How is a presence check tested?

Key term

How is a range check on a numeric field tested?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Why is every validation rule given a test of its own?

    Model answer

    A rule that was never tested may have been left out of the code altogether, and nothing else would reveal it.

  2. 2

    How is a presence check tested?

    Model answer

    The field is left empty and the record is saved, and the solution should refuse and say what is missing.

  3. 3

    How is a range check on a numeric field tested?

    Model answer

    Values just inside, exactly on and just outside each limit are entered, and only the allowed ones should be accepted.

  4. 4

    How is a format check tested?

    Model answer

    A value in the correct pattern and several in wrong patterns are entered, and only the correct pattern should be accepted.

  5. 5

    What should be observed besides whether the entry was accepted or rejected?

    Model answer

    The message shown to the user is observed, because a rejection with no explanation leaves the user stuck.

  6. 6

    State three things a good error message should do.

    Model answer

    A good error message names the field, says what is wrong with the entry, and says what the user should do next.

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