Assertions are validation rules applied to test results that check how your target web service performs.
Let's create an assertion that will check that the target web service responds within a time limit:
Switch to the initially created request.
Expand the Assertions tab and click Add Assertion.
In the Add Assertion dialog, select SLA > Response SLA and click Add.
Specify the maximum expected response time and click OK.
Now, if the test step takes longer than the specified number of milliseconds to complete, the assertion will trigger, and the test will fail.
Let's also verify that the returned location is consistent:
Expand the Assertions tab and click again.
In the Add Assertion dialog, select Property Content > XPath match and click Add.
Click to select an XML node from the response.
Select geometry/location/lat and click OK.
SoapUI will create the XPath expression to access the response item, and set the result from the last response as the expected result. Click Save to create the assertion.
Now, if the response changes, the assertion will trigger and the test step will fail.