Technology sharing | how to do Assertion Verification in interface automated testing?

In the process of server-side automated testing , After the request is initiated, the response value needs to be verified . After verifying that the response information meets the expected value , This interface automation test case can be considered as a complete pass . So this chapter , It will be explained in the interface automation test , How to assert and verify the response content returned by the server .

Practice

Initiate interface service HTTP Request information , After obtaining the response content , Make Assertion Verification .

Python Demo code

After initiating the request , Use a variable r Store the contents of the response , That is to say Response object .

r = requests.get("https://httpbin.ceshiren.com/get")

In response to the results ：

{
  "args": {},
  "headers": {
    "Accept": "*/*",
    "Accept-Encoding": "gzip, deflate",
    "Host": "httpbin.ceshiren.com",
    "User-Agent": "python-requests/2.25.1",
    "X-Forwarded-Host": "httpbin.ceshiren.com",
    "X-Scheme": "https"
  },
  "origin": "119.123.205.82",
  "url": "https://httpbin.ceshiren.com/get"
}

Response Object has many powerful methods to call , For example, get the response header directly , obtain Unicode The encoded response content , Get binary response content , Get the original response content and so on .

Response assertion

Response status code assertion

• Assert success

import requests
r = requests.get('https://httpbin.ceshiren.com/get')
assert r.status_code==200

assert yes python Built in functions for , Used to determine the expression , When the expression condition is False An exception will be triggered when .r.status_code yes response Object , The status code used to get the return value .assert r.status_code==200 Is to judge whether the status code is equal to 200, If not equal to 200 An exception will be thrown .

• Assertion failed

>>> import requests
>>> r = requests.get('https://httpbin.ceshiren.com/get')
>>> assert r.status_code==400
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AssertionError

From the above example, we can see , The actual output of this response status code is consistent with the expected result status code 400 It's not equal , So an exception was thrown .

Json Response assertion

data = {
      "hogwarts": ["a","b","c"]
  }
r = requests.post('https://httpbin.ceshiren.com/post',json=data)
print(json.dumps(r.json(),indent=2))
assert r.status_code == 200
assert r.json()["json"]["hogwarts"][0] == "a"

In response to the results ：

"args": {},
  "data": "{"hogwarts": ["a", "b", "c"]}",
  "files": {},
  "form": {},
  "headers": {
    ... Omit ...
  },
  "json": {
    "hogwarts": [
      "a",
      "b",
      "c"
    ]
  },
  "origin": "113.89.8.68",
  "url": "https://httpbin.ceshiren.com/post"
}

adopt assert r.json()[“json”][“hogwarts”][0] == “a” Yes json Assert the content of , among r.json() Is to get the corresponding content ,r.json()[“json”] It's about getting json The content of ,r.json()[“json”][“hogwarts”] It's about getting hogwarts The content of ,r.json()[“json”][“hogwarts”][0] yes hogwarts The first data under .

Java Demo code

Java adopt then Perform assertion validation ,then() Method can verify many different types of response information .

• Assert that the response status code is successful

import static io.restassured.RestAssured.*;

public class Requests {
    public static void main(String[] args) {
        given().when().get("https://httpbin.ceshiren.com/get").
                // Usually by  then  Perform assertion validation  
                then().statusCode(200);
    }
}

adopt then() Method statusCode() Method to verify the response status code ,statusCode() Methods usually receive int Parameters of type .statusCode(200) Indicates whether the response status code is equal to 200, If not equal to 200 An exception will be thrown .

If you change the code verified by the above code interruption to statusCode(300), Then the console will output exception information .

Exception in thread "main" java.lang.AssertionError: 1 expectation failed.
Expected status code <300> but was <200>.

json Response assertion

import static io.restassured.RestAssured.*;
import static org.hamcrest.core.IsEqual.equalTo;

public class Requests {
    public static void main(String[] args) {
        given().when().get("https://httpbin.ceshiren.com/get").
                then().body("headers.Host", equalTo("httpbin.ceshiren.com")).log().all();
    }
}

adopt then().body(“headers.Host”, equalTo(“httpbin.ceshiren.com”)) Yes json Assert the content of , among then().body() Is to get the corresponding content , The first parameter is to extract the actual field value from the response content , The second parameter calls equalTo() Method , And the expected result is introduced into it .