by, 04-27-2012 at 08:28 PM (3315 Views)
Assertions allow you to assert facts about responses received from the server being tested. Using an assertion, you can essentially "test" that your application is returning the results you expect it to.
For instance, you can assert that the response to a query will contain some particular text. The text you specify can be a Perl-style regular expression, and you can indicate that the response is to contain the text, or that it should match the whole response.
You can add an assertion to any Sampler. For example, you can add an assertion to a HTTP Request that checks for the text, "</HTML>". JMeter will then check that the text is present in the HTTP response. If JMeter cannot find the text, then it will mark this as a failed request.
To view the assertion results, add an Assertion Listener to the Thread Group. Failed Assertions will also show up in the Tree View and Table Listeners, and will count towards the error %age for example in the Aggregate and Summary reports.