new test case added for SOL003 VNFIndicator Subsriptions

SOL003/VNFIndicator-API/Subscriptions.robot

@@ -173,3 +173,16 @@ GET VNF Indicator Subscriptions - Bad Request Response too Big
     Get All VNF Indicators Subscriptions
     Check HTTP Response Status Code Is    400
     Check HTTP Response Body Json Schema Is   ProblemDetails 
+
+POST Create a new Subscription - Unprocessable Entity
+    [Documentation]    Test ID: 7.3.6.4.13
+    ...    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 8.4.5.3.1 - ETSI GS NFV-SOL 003 [1] v2.6.1
+    ...    Config ID: Config_prod_VNFM
+    ...    Applicability: none
+    ...    Post-Conditions: none
+    Send Post Request for VNF Indicator Subscription
+    Check HTTP Response Status Code Is    422
+    Check HTTP Response Body Json Schema Is  ProblemDetails