I configured with SoapUI 5.0 a MockService using a copy of this WSDL definition (http://www.webservicex.com/globalweather.asmx?WSDL).
I cant test against the MockService with PHP SoapClient just fine:
ini_set("soap.wsdl_cache_enabled", 0);
$client = new \SoapClient("http://172.20.1.52:8088/mockGlobalWeatherSoap?WSDL", array('trace' => 1));
$response = $client->__soapCall('GetCitiesByCountry', array());
However, I started to play with the definition to ensure mandatory parameters for some methods.
For example, I wanted to ensure CountryName to be a mandatory parameters for the GetCitiesByCountry() method:
<s:element name="GetCitiesByCountry">
<s:complexType>
<s:sequence>
<s:element minOccurs="1" maxOccurs="1" name="CountryName" type="s:string" />
</s:sequence>
</s:complexType>
</s:element>
However, whatever I throw at SoapUI, my MockService will always send me a correct response diregarding whether the parameter has been provided or not.
How to ensure the basic validation as described in the WSDL file in SoapUi?
I tried the same thing from within SoapUI with sending a dummy soap request with missing parameters but SoapUI doesn't care and sends me a response back.
SoapUI mocking does not simulate what is in the WSDL. It will only simulate a response. You have to configure SoapUI to simulate the specific response that you want.
Did you try the SoapUI documentation? http://www.soapui.org/Service-Mocking/simulating-complex-behaviour.html