Understanding and testing Web Services

Available at http://mwtestconsultancy.co.uk/presentations/understanding_web_services_lite

Please load up Google Chrome and install

Workshop goals

Explore what is a Web Service

Build different requests to query and manipulate data

Try out different test design techniques

Going forward...

RESTFUL-BOOKER

Restful-booker requirements

1. Be able store Bookings with the following items
   • Guests name
   • The price of their booking
   • Whether they have paid a deposit
   • The dates of their booking
   • Any additional needs
2. Must be able to create, read, update and delete bookings
3. Bookings must be searchable

Restful-booker API

POSTMAN

Our test tool for the workshop

Web Service

'A Web service is a software system designed to support interoperable machine-to-machine interaction over a network.'

Mobile to Web Service

UI

Backend

Web Service to Web Service

Reports

Search

A service-oriented architecture

A Web Service example

A typical HTTP Read request

Uniform Resource Identifiers

Uniform Resource Identifiers

scheme ://host :port /resource ?queryString

http://localhost:3001/booking?name=mary

Query strings

A query string indicates additional actions you might want to apply to the resource you want

GET /booking?checkin=2014-03-13&checkout=2014-05-21

GET /booking

Creating query strings

• Query strings start with a ? after the resource path
• Are declared as key=value
• Multiple query declarations are joined using &

GET /booking?checkin=2014-03-13&checkout=2014-05-21

A typical HTTP request

Verbs in action

OPTION http://localhost:3001/booking

Returns which Verbs can be used on a URI

A typical HTTP response

Types of Payloads

"booking": {
  "firstname": "Sally",
  "lastname": "Brown",
  "totalprice": 111,
  "depositpaid": true,
  "additionalneeds": "Breakfast",
  "bookingdates": {
    "checkin": "2013-02-23",
    "checkout": "2014-10-23"
  }
}

<created-booking>
  <booking>
    <firstname>Sally</firstname>
    <lastname>Brown</lastname>
    <totalprice>111</totalprice>
    <depositpaid>true</depositpaid>
    <additionalneeds>Breakfast</additionalneeds>
    <bookingdates>
      <checkin>2013-02-23</checkin>
      <checkout>2014-10-23</checkout>
    </bookingdates>
  </booking>
</created-booking>

A typical HTTP response

HTTP Status codes

Indicator of how the server has responded to the request you've sent

Typical HTTP Status codes

A typical HTTP create request

Payload

A representation of the resource you want to create through the service

The parameters and the structure of the payload have strict rules

Which can also be known as a 'contract'

Data types

						{
	"firstName": "Mark",
	"lastName": "test",
	"totalPrice": 300.00,
	"depositPaid": true,
	"additionalNeeds": "Breakfast",
	"bookingDates": {
		"checkIn": "11/11/2014",
		"checkOut": "12/11/2014"
	}
}
					

Robustness principle

• When sending a payload the service should conform to the contract being sent
• When receiving a payload the service should accept invalid data without error

A typical HTTP Read request

HTTP Headers

Define the operating parameters of an HTTP request such as:

• What is requesting the resource
• What format the resource should be in
• Authorisation that the resource can be requested

And more: https://en.wikipedia.org/wiki/List_of_HTTP_header_fields

HTTP Headers

Adding headers can alter the behaviour of the service and its response

Authorisation

Services generally have one or more layers of security such as:

• Basic access authentication
• Cookie based authentication

This isn't an exhaustive list

There may be other layers of security in place

Basic access authentication

Comes in the form of a header

Cookie based authentication

{
  username: admin,
  password: password123
}

Set-Cookie: token=abc123

Cookie: token=abc123

PUT

Similar to POST but rather than create it updates

However, in the real world that might not be the case:

PUT vs POST

DELETE

Similar to GET but it deletes rather than reads the resource

Taking Web Service testing further

Mobile to Web Service

UI

UI testing

Backend

Web service testing

Automation?

Wrapping up

Thank you