In my experience, it means that you have to treat your tests with nearly as much software engineering respect and prowess as your real code. You have to factor things out and try to avoid DRY (particularly tough sometimes in testing) as much as possible.
If there is one "concept" that you're asserting in your test suite, you want that concept to only be repeated once or as close to once as you can get. Often times, people copy paste sets of assertions that have mixed concepts. Then, when a requirement changes, hundreds of tests end up having to be updated.
This is why many large companies, that contract out test automation development or train manual QA people with enough programming skills to write tests, end up with brittle test suites. One look at those test suites by an experienced developer and it's no wonder: there's conceptual/semantic duplication everywhere.
If there is one "concept" that you're asserting in your test suite, you want that concept to only be repeated once or as close to once as you can get. Often times, people copy paste sets of assertions that have mixed concepts. Then, when a requirement changes, hundreds of tests end up having to be updated.
This is why many large companies, that contract out test automation development or train manual QA people with enough programming skills to write tests, end up with brittle test suites. One look at those test suites by an experienced developer and it's no wonder: there's conceptual/semantic duplication everywhere.