Testing Mistakes

Note: This text is taken from http://www.testing.com/writings/classic/mistakes.html

The role of testing

• Thinking the testing team is responsible for assuring quality.
• Thinking that the purpose of testing is to find bugs.
• Not finding the important bugs.
• Not reporting usability problems.
• No focus on an estimate of quality (and on the quality of that estimate).
• Reporting bug data without putting it into context.
• Starting testing too late (bug detection, not bug reduction)

Planning the complete testing effort

• A testing effort biased toward functional testing.
• Underemphasizing configuration testing.
• Putting stress and load testing off to the last minute.
• Not testing the documentation
• Not testing installation procedures.
• An overreliance on beta testing.
• Finishing one testing task before moving on to the next.
• Failing to correctly identify risky areas.
• Sticking stubbornly to the test plan.

Personnel issues

• Using testing as a transitional job for new programmers.
• Recruiting testers from the ranks of failed programmers.
• Testers are not domain experts.
• Not seeking candidates from the customer service staff or technical writing staff.
• Insisting that testers be able to program.
• A testing team that lacks diversity.
• A physical separation between developers and testers.
• Believing that programmers can't test their own code.
• Programmers are neither trained nor motivated to test.

The tester at work

• Paying more attention to running tests than to designing them.
• Unreviewed test designs.
• Being too specific about test inputs and procedures.
• Not noticing and exploring "irrelevant" oddities.
• Checking that the product does what it's supposed to do, but not that it doesn't do what it isn't supposed to do.
• Test suites that are understandable only by their owners.
• Testing only through the user-visible interface.
• Poor bug reporting.
• Adding only regression tests when bugs are found.
• Failing to take notes for the next testing effort.

Test automation

• Attempting to automate all tests.
• Expecting to rerun manual tests.
• Using GUI capture/replay tools to reduce test creation cost.
• Expecting regression tests to find a high proportion of new bugs.

Code coverage

• Embracing code coverage with the devotion that only simple numbers can inspire.
• Removing tests from a regression test suite just because they don't add coverage.
• Using coverage as a performance goal for testers.
• Abandoning coverage entirely.