Postman – Schema Validation

Schema validation of an API request can be used to validate if the API returns the expected response. It is being used widely in consumer contract testing.

Let’s modify a bit the example of the request from our previous post: http://trikalabs.com/postman-mock-server/.

1. Change the example response to the following array:
   
   Swift

   [ { "registrationNumber" : "ABCD11", "make": "BMW", "model": "z1" }, { "registrationNumber" : "ABCD12", "make": "BMW", "model": "z1" }, { "registrationNumber" : "ABCD13", "make": "BMW", "model": "z1" } ]

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

   [         {             "registrationNumber" : "ABCD11",             "make": "BMW",             "model": "z1"         },                 {             "registrationNumber" : "ABCD12",             "make": "BMW",             "model": "z1"         },                 {             "registrationNumber" : "ABCD13",             "make": "BMW",             "model": "z1"         }     ]

2. Now let’e select the test tab:
   
3. And write our schema:
   
   Swift

   const jsonSchema = { "type": "array", "items": { "type": "object", "Properties": { "registrationNumber": { "type": "string" }, "make": { "type": "string" }, "model": { "type": "string" } } } };

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

   const jsonSchema = {     "type": "array",     "items": {         "type": "object",         "Properties": {             "registrationNumber": {                 "type": "string"             },             "make": {                 "type": "string"             },             "model": {                 "type": "string"             }         }     } };

4. And write our validation test
   
   Swift

   pm.test("Schema Validation", () => { pm.response.to.have.jsonSchema(jsonSchema); });

   1 2 3

   pm.test("Schema Validation", () => {     pm.response.to.have.jsonSchema(jsonSchema); });

5.  And let’s run it:
   

Test is passing!