Add tests for request body mapper

openapi-cli/src/test/resources/ballerina-to-openapi/expected_gen/parameter_annotation/annotated_payload_complex.yaml

@@ -68,6 +68,33 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/ErrorPayload'
+  /student3:
+    post:
+      operationId: postStudent3
+      parameters:
+        - name: q
+          in: query
+          required: true
+          schema:
+            type: string
+      requestBody:
+        content:
+          text/plain:
+            schema:
+              type: string
+      responses:
+        "201":
+          description: Created
+          content:
+            application/json:
+              schema:
+                type: object
+        "400":
+          description: BadRequest
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorPayload'
 components:
   schemas:
     ErrorPayload:

openapi-cli/src/test/resources/ballerina-to-openapi/parameter_annotation/annotated_payload_complex.bal

@@ -14,4 +14,8 @@ service /payloadV on ep0 {
     resource function post student2(@http:Payload string p, string q) returns json {
         return {Name: p};
     }
+
+        resource function post student3(@http:Payload string? p, string q) returns json {
+            return {Name: p ?: q};
+        }
 }

openapi-cli/src/test/resources/ballerina-to-openapi/record/with_readonly_keyword.bal

@@ -29,7 +29,7 @@ service /payloadV on new http:Listener(port) {
         }
     }
 
-    resource function post albums(@http:Payload Album album) returns Album {
+    resource function post albums(@http:Payload readonly & Album album) returns Album {
         albums.add(album);
         return album;
     }