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Three Reasons Test-First Doesn't Guarantee Thorough Testing

publish date: 2026/06/04 11:00:3.916576 UTC

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Test-first development and automated testing usually results in a large number of tests. However, this approach does not necessarily lead to thorough program testing. Which of the following are the three stated reasons? Select all that apply.

Programmers prefer programming to testing and sometimes take shortcuts — writing incomplete tests that do not check all possible exceptions

It is difficult to judge the completeness of a test set — crucial parts of the system may not be executed and so remain untested

Automated tests always produce false positives that mislead developers

Customer-written acceptance tests always conflict with developer-written unit tests

Some tests can be very difficult to write incrementally — for example in a complex user interface where it is often difficult to write unit tests for display logic

Correct Answer

(1) Programmers prefer programming to testing and sometimes take shortcuts — writing incomplete tests that do not check all possible exceptions

(2) Some tests can be very difficult to write incrementally — for example in a complex user interface where it is often difficult to write unit tests for display logic

(3) It is difficult to judge the completeness of a test set — crucial parts of the system may not be executed and so remain untested

Explanation

Three reasons test-first does not guarantee thorough testing: (1) programmers take shortcuts — writing incomplete tests that miss some exceptions; (2) some tests are hard to write incrementally — particularly for complex UI display logic; (3) completeness is hard to judge — you may have many tests yet crucial parts remain untested.

Reference

Software Engineering, Ian Sommerville, 9th edition

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