API Functional Tests with Cucumber and Rest-assured

On projects where multiple systems undergo development at the same time, it’s crucial to maintain a clear picture of how they should interact. We commonly have a back-end system providing a REST API to multiple front-ends (browsers, mobile apps, chatbots, IoT, etc.). Because it will likely change over time, keeping the API picture clear and up to date can be a significant challenge. How can we efficiently describe the currently expected behavior and know if it’s working as expected?

In this case to provide a readable test scenarios it’s a good opportunity to use Cucumber.Cucumber helps us write readable requirements upfront that can be tied directly to executable tests. Here’s an example for a guestbook REST API:

I hope you have the basic knowledge about cucumber, if not you can found useful information about cucumber and rest-assured

In this post will present some generics post what will help you to test REST API, let’s start with :

Given user sets content type with value 'application/json'

this step sets content type for the request what you will perform, implementation:

@Given("^user sets content type with value '(.*)'$")
public void userSetsContentTypeWithValue(String contentType) {
RequestSpecification request = (RequestSpecification) scenarioContext.getData(RestKeys.REQUEST);
request.header("Content-Type", contentType);
}

Found a way to send JSON format with cucumber, this is one of more powerful step in automation process:

 Then the following json response is sent
"""
 {
    'dddd': 'dddd',
    'ggggg': 'ggggg',
    'somethingelse': {
      'thing': 'thingvalue',
      'thing2': 'thing2value'
    }
  }
"""

@Then("^the following json response is sent$")
public void theFollowingJsonResponseIsSent(String message) {
    request.body(message);
    request.post(kafkaTopics.concat(topicName));
}

Next is to verify response reason code:

Then the status code is 200

and implementation:

@Then("the status code is (\\d+)")
public void verifyStatusCode(int statusCode) {
    json = response.then().statusCode(statusCode);
}

And steps to check the response what we reserved:

And response includes the following
  | totalItems | 1             |
  | kind       | books#volumes |
And response includes the following in any order
  | items.volumeInfo.title     | Steve Jobs         |
  | items.volumeInfo.publisher | Simon and Schuster |
  | items.volumeInfo.pageCount | 630                |



Implementation for this steps is bellow:
/**
 * asserts on json fields with single values
 */
@When("response includes the following$")
public void response_equals(Map<String, String> responseFields) {
    for (Map.Entry<String, String> field : responseFields.entrySet()) {
        if (StringUtils.isNumeric(field.getValue())) {
            json.body(field.getKey(), equalTo(Integer.parseInt(field.getValue())));
        } else {
            json.body(field.getKey(), equalTo(field.getValue()));
        }
    }
}

@Then("response includes the following in any order")
public void response_contains_in_any_order(Map<String, String> responseFields) {
    for (Map.Entry<String, String> field : responseFields.entrySet()) {
        if (StringUtils.isNumeric(field.getValue())) {
            json.body(field.getKey(), containsInAnyOrder(Integer.parseInt(field.getValue())));
        } else {
            json.body(field.getKey(), containsInAnyOrder(field.getValue()));
        }
    }
}

Hope this will help you, how this helped me. Enjoy!