API Testing -with POSTMAN

 Web services supported by POSTMAN:

Type of webservices

·         SOAP

·         REST

Installation of POSTMAN

·         Install as google plug in

·         Download as application

Use below URL for sample test rest API requests : https://reqres.in/

Tips:

·         JSON beautifier is used to check the data format

·         Testing rest services using POSTMAN

POSTMAN IDE:

·         Workspace: stores all collections

·         Collections: collections of requests

·         Test suits : contains tests or test cases

HTTP request Methods

·         Create a record- POST

·         Retrieve/verify data – GET

·         Update data – PUT

·         Delete data – DELETE

URL : domain + URI (also call as endpoints)

 Steps to write test cases

·         Get the request run and manually work

·         Understand/parse the request body

·         Write test

Working with get requests steps:

·         Take sample Get request with parameters

·         Go to tests section

·         Use the existing snippet as beginner

·         Write modern code use ES6 javascript code

·         Status code, json body value check

Working with post request steps

·         Let date=date.now() console.log(date)

·         Under pre-req set the prereq actions or steps

·         Set global variables (pm.globals.set(“currentdate”,date)

·         To use environment variable use double curly brackets in request body ex. “currentdate”:{{currentDate}}

 API Architecture

API calls Collection include mainly three things:

1.            HTTP headers

2.            HTTP Request  (POST,GET,PUT,DELETE )

3.            Status Code/ Response Code

Apart from this your application collection include many things if it required to test in you application.

1.       HTTP headers  - HTTP headers are always depended on your application, Mainly two:

·         Authorization - A token included with requests to identify the requester. This header has to be included in all requests other than the login request.

·         Content-Type - A standard MIME type describes the format of object data.Content –type in most of the requests and responses will be application/json.

 2.       HTTP Request  -  There are mainly four request, which we used frequently: DATA =

·         POST - Create Or Update data

·         PUT - Update data

·         GET - Retrieve data

·         DELETE – Delete data

3.       Status Code/Response Code - There are many status/response code, from them we can verify the response.

1.            200 - OK, The request was successful.

2.            201 - Created, The request was successful and data was created.

3.            204 - No Content, The response is empty.

4.            400 - Bad Request, The request could not be understood or was missing required parameters.

5.            401 – Unauthorized, Authentication failed or user does not have permissions for the requested operation.

6.            403 - Forbidden, Access denied.

7.            404 - Not Found, Data was not found.

8.            405 - Method Not Allowed, Requested method is not supported for the specified resource.

9.            500 - Internal Server Error.

10.        503 - Service Unavailable, The service is temporary unavailable.

Postman tips

·         Postman console for debugging- if any error occurred during test snippets, you can verify it using postman console window

·         Postman code generator- below save button, there is link as Code

·         To generate delay between requests- on request > Test tab – set Timeout(()=>{},10000) (10000 means 10 sec)

·         To skip the test in postman request- Go to Test and lets say you have 5 validation out of which need to skip one, you need to write pm.test.skip(“Testname”,function(){pm.expect(response.origin).to.eql(100);});

·         Conditional skip – const islocal=pm.environment.get(‘environment’)==’local’; (islocal?pm.test.skip: pm.test(“Testname”,function(){pm.expect(response.origin).to.eql(100);});

Cheers,

TJ