API Testing with Cucumber, The Most Popular BDD Framework

API testing with Cucumber is really innovative way of using BDD style feature file. cucumber-api lets one validate public APIs JSON response in blazingly fast time.

Inspired by cucumber-api-steps.

Checkout sample to see cucumber-api in action.

Installation

Add cucumber-api gem to your Gemfile:

gem 'cucumber-api'

Require cucumber-api in your Cucumber’s env.rb:

require 'cucumber-api'

Configuration

Verbose logging: enable verbose logging of API calls and responses by settingcucumber_api_verbose=true in your ENV, preferably via your cucumber.yml

# config/cucumber.yml
##YAML Template
---
verbose     : cucumber_api_verbose=true

Usage

Available steps

Preparation steps

Specify your request header’s Content-Type and Accept. The only supported option for Accept isapplication/json at the moment.

Given I send and accept JSON
Given I send "(.*?)" and accept JSON

Specify POST body

When I set JSON request body to '(.*?)'
When I set form request body to:
  | key1 | value1              |
  | key2 | {value2}            |
  | key3 | file://path-to-file |

Or from YAML/JSON file

When I set request body from "(.*?).(yml|json)"

Example:

Given I send "www-x-form-urlencoded" and accept JSON
When I set JSON request body to '{"login": "email@example.com", "password": "password"}'
When I set form request body to:
  | login    | email@example.com     |
  | password | password              |
When I set request body from "data/json-data.json"
When I set request body from "data/form-data.yml"

Request steps

Specify query string parameters and send an HTTP request to given URL with parameters

When I send a (GET|POST|PATCH|PUT|DELETE) request to "(.*?)"
When I send a (GET|POST|PATCH|PUT|DELETE) request to "(.*?)" with:
  | param1 | param2 | ... |
  | value1 | value2 | ... |

Temporarily save values from the last request to use in the next request in the same scenario:

When I grab "(.*?)" as "(.*?)"

The saved value can then be used to replace {placeholder} in the next request.

Example:

When I send a POST request to "http://example.com/token"
And I grab "$..request_token" as "token"
And I grab "$..access_type" as "type"
And I send a GET request to "http://example.com/{token} with:
  | type            | pretty |
  | {type}          | true   |

Assume that http://example.com/token have an element {"request_token": 1, "access_type": "full"}, cucumber-api will execute the followings:

• POST http://example.com/token
• Extract the first request_token and access_type from JSON response and save it for next request
• GET http://example.com/1?type=full&pretty=true
• Clear all saved values

This will be handy when one needs to make a sequence of calls to authenticate/authorize API access.

Assert steps

Verify:

• HTTP response status code
• JSON response against a JSON schema conforming to JSON Schema Draft 4
• Adhoc JSON response key-value type pair, where key is a JSON path

Then the response status should be "(\d+)"
Then the JSON response should follow "(.*?)"
Then the JSON response root should be (object|array)
Then the JSON response should have key "([^\"]*)"
Then the JSON response should have (required|optional) key "(.*?)" of type (numeric|string|array|boolean|numeric_string|object|array|any)( or null)

Example:

Then the response status should be "200"
Then the JSON response should follow "features/schemas/example_all.json"
Then the JSON response root should be array
Then the JSON response should have key "id"
Then the JSON response should have optional key "format" of type string or null

Also checkout sample for real examples. Run sample with the following command:

cucumber -p verbose

Response caching

Response caching is provided for GET requests by default. This is useful when you have a Scenario Outline or multiple Scenarios that make GET requests to the same endpoint.

Only the first request to that endpoint is made, subsequent requests will use cached response. Response caching is only available for GET method.

Dependencies

• cucumber for BDD style specs
• jsonpath for traversal of JSON response via JSON path
• json-schema for JSON schema validation
• rest-client for HTTP REST request

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