Technology Sharing | How to do assertion verification for xml format in interface automation testing?

In the process of server-side automated testing, the response value needs to be verified after the request is initiated. After verifying that the response information conforms to the expected value, this interface automated test case is considered a complete pass.Therefore, in this chapter, we will explain how to perform assertion verification on the XML format response content returned by the server in the interface automation test.

Environment preparation

Python version

Install requests_xml

pip install requests_xml

Java version

Rest-Assured supports xml assertion, refer to the interface testing framework chapter to install Rest-Assured.

XML parsing

Python has three ways of parsing XML.

• DOM mode: It is the document object model and a standard programming interface recommended by the W3C organization. It parses XML data into a tree in memory, and manipulates XML by manipulating the tree.

• SAX mode: It is an event-driven model for processing XML. It scans the document line by line and parses it as it scans. It has huge advantages for parsing large documents. Although it is not a W3C standard, it getswidely recognized.

• ElementTree method: Compared with DOM, it has better performance, similar to SAX performance, and the API is also very convenient to use.

Python version

request is not strong in encapsulating the XML format, you can use the request_xml third-party library, or you can encapsulate an XML parsing by yourself.

• XML Response Assertion

from requests_xml import XMLSession# set sessionsession = XMLSession()r = session.get("https://www.nasa.gov/rss/dyn/lg_image_of_the_day.rss")# print everythingr.text# links can get all the link addresses in the responser.xml.links# raw_xml returns the response content in bytesr.xml.raw_xml# text returns the content of the labelr.xml.text

• Assertions using xpath

The

requests_xml library also supports XPath expressions.You can retrieve the data of the corresponding field in the response through XPath, and put the retrieved data in the result list, which is convenient for use case assertion.

XPath usage:

def xpath(self, selector: str, *, first: bool = False, _encoding: str = None) -> _XPath:"""Given an XPath selector, returns a list of:class:`Element ` objects or a single one.:param selector: XPath Selector to use.:param first: Whether or not to return just the first result.:param _encoding: The encoding format."""

selector: XPath expression used

first: whether to return only the first search result

The

xpath() method returns a list of found objects.

def test_xpath():session = XMLSession()r = session.get("https://www.nasa.gov/rss/dyn/lg_image_of_the_day.rss")# Get the content of all link tags through xpathitem = r.xml.xpath("//link")result = []for i in item:# put the obtained results into a listresult.append(i.text)# assertassert 'http://www.nasa.gov/' in result

• XML parsing

XML is a structured, hierarchical data format, and the most suitable data structure for XML is a tree.The XML structure can be parsed using the xml.etree.ElementTree that comes with python.ElementTree can convert the entire XML document into a tree, and the interaction (reading, writing, finding elements) of the entire XML document is generally carried out at the ElementTree level.

Then use the findall method to find the required XPath data.

import xml.etree.ElementTree as ET# Encapsulate the xml parsing method yourselfsession = XMLSession()r = session.get("https://www.nasa.gov/rss/dyn/lg_image_of_the_day.rss")# Get the response contentroot = ET.fromstring(r.text)# find root elementem = root.findall(".")# print(item)items = root.findall(".//link")result = []# traversefor i in items:result.append(i.text)assert "http://www.nasa.gov/" in result

Java version

Call the body() method, the first passing in the XPath expression and the second passing the desired result.

import static io.restassured.RestAssured.*;import static org.hamcrest.core.IsEqual.equalTo;public class Requests {public static void main(String[] args) {given().contentType("application/rss+xml; charset=utf-8").when().get("https://www.nasa.gov/rss/dyn/lg_image_of_the_day.rss").then().body("rss.channel.item[0].link",equalTo("http://www.nasa.gov/image-feature/mocha-swirls-in-jupiter-s-turbulent-atmosphere")).log().all();}}

The following is the XML response content of this request. This type of XPath expression rss.channel.item[0].link is easy to understand, and it is located according to the level of XPath itself.rss is its outermost label, followed by the channel label, item label, and link label. The item at the same level has multiple labels, so it is necessary to locate the first item label by subscript [0].Through this positioning method, the desired response content can also be obtained.

http://www.nasa.gov/image-feature/mocha-swirls-in-jupiter-s-turbulent-atmosphere...omit...omit...omit...