Schema Compliance Assertion soapUI

As mentioned in other posts, one should be able to tell the details of a web service by looking into its WSDL.So a WSDL should have the syntax, data types, input/ output message structures defined in XML format. This called as the XML Schema. 

Now, let us see what a Schema Compliance assertion does in soapUI. In simple words, it checks the syntax or the definitions specified in WSDL is matching with the soap Response of a test request. For example, let us say there is an element in the response defined as of type "double". That means the web service expects only numeric/double value in the specific field. In this case, if for some reason, the response is returning a string instead of a numeric value, the soapUI Schema Compliance assertion will catch the difference and it will fail the assertion. See below a sample image of failed Schema Compliance assertion.

This doesn't mean that always it should be an issue with data type to for this assertion to fail. Even when there is a difference in the order of the response elements when compare to the WSDL/Schema, that too can be caught by using this assertion. If you are testing a web service using soapUI for a company that sells web services as one of its products, then make sure you have this assertion added to your tests.