new test added for subscription

SOL002/VNFFaultManagement-API/Subscriptions.robot

@@ -285,6 +285,19 @@ Get subscriptions with filter "filter.probableCauses"
     Check HTTP Response Body Json Schema Is   FmSubscriptions
     Check PostCondition HTTP Response Body Subscriptions Matches the requested attribute-based filter "filter_probableCauses"
     
+POST Create a new Subscription - Unprocessable Entity
+    [Documentation]    Test ID: 6.3.4.4.21
+    ...    Test title: POST Create a new Subscription - Unprocessable Entity
+    ...    Test objective: The objective is to test that content type of the payload body is supported and the payload body of a request contains syntactically correct data but the data cannot be processed.
+    ...    re-conditions: none
+    ...    Reference: Clause 7.4.5.3.1 - ETSI GS NFV-SOL 002 [2] v2.6.1
+    ...    Config ID: Config_prod_VNFM
+    ...    Applicability: none
+    ...    Post-Conditions: none
+    Post Create subscription
+    Check HTTP Response Status Code Is    422
+    Check HTTP Response Body Json Schema Is  ProblemDetails
+
 *** Keywords ***
 Post Create subscription
     Log    Create subscription instance by POST to ${apiRoot}/${apiName}/${apiVersion}/subscriptions