When is parameterization used?
For example: a module needs to be tested with multiple sets of different data == to verify the correctness of the business
Login module: Correct username, password === Success; Wrong username, correct password === Failure
Postman implements parameterization
In actual interface testing, some parameters must be unique each time a request is sent (such as registration). In this case, postman can be used to parameterize the test data.
There are three main ways for postman to set parameters:
- Built-in variable implementation
- Use code in the Pre-request Script tab (recommended)
- Implemented in the form of external files; such as csv files/json format files
1. Implementation of built-in variables
Postman has the following three built-in variables, suitable for one-time use; Disadvantage: Internal key variables cannot be compared accurately
{ {$guid}}: Generation GUID; Follow the instructions:
{ {$timestamp}}: current timestamp; as shown below
You can check the time through the online timestamp conversion tool: https://tool.lu/timestamp/
{ {$randomInt}}: Random integer from 0-1000
2. Use code in the Pre-request Script tab to implement it (recommended)
Pre-request Script is the operation to be done before executing the interface request, and tests is the operation to be done after executing the request. Built-in variables are generally placed in Request. We can also use code to implement them in Pre-request Script. The advantage of using code is that they can be reused.
Pre-request Script is the same as test and supports javascript syntax
Several parameterizations implemented inPre-request Script; as shown below
//Get the current timestamp in milliseconds
var now_time = Date.now()
pm.globals.set("now_time",now_time)
//guid implementation
const guid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'
.replace(/x/g, () => (Math.floor(Math.random() * 16)).toString(16))
.replace(/y/g, () => (Math.floor(Math.random() * 4 + 8)).toString(16));
pm.globals.set("guid_value",guid)
//Random integer implementation
const randomInt = (min, max) => Math.floor(Math.random() * (max - min + 1)) +
min
pm.globals.set("randomInt_num",randomInt(8,15))
//Select implementation from multiple options
const randomInt = (min, max) => Math.floor(Math.random() * (max - min + 1)) +
min
const getRandomValue = list => list[randomInt(0, list.length - 1)];
const charsInName = ['Wang','Li','Zhang']
pm.globals.set("people_name",getRandomValue(charsInName))
//Realize random mobile phone number
const randomInt = (min, max) => Math.floor(Math.random() * (max - min + 1)) +
min
var mobile_num = `18${randomInt(100000000, 999999999)}`;
pm.globals.set("mobile_num",mobile_num)
//Synchronization waiting implementation: wait for 5 seconds before starting execution
const sleep = (milliseconds) => {
const start = Date.now();
while (Date.now() <= start + milliseconds) {}
}
sleep(5000)
Practical example: writing code throughPre-request Script can accurately compare assertions in random parameters
1. Write code in Pre-request Script
2. Reference variables in the request; { {Variable name}}
3. Make assertions in tests to verify whether the actual results are consistent with the expected results.
4. View execution results
3. Parameterization through external files
In postman, in addition to the above two methods to achieve parameterization, you can also use external data files (supporting csv files and data containing json format text). External data files can currently be imported through the Runner tab.
csv file format example:
For csv files to work in Collection Runner, the first line must be the variable name to be used in the request. Each line is a use case and represents an iteration.
1. First prepare the csv file, the encoding is UTF-8; as shown above
2. Quote the variable name in postman. In the following figure, the wd parameter in Baidu search introduces { {search_word}}, the assertion in the tests tab refers to data.expected_result
3. Click the Runner button, check the request to be executed, set the number of cycles, import the csv file, and click run to execute; as shown below
4. View execution results
json file you need to make sure your file has an array of key/value pairs. Each element in the array is a key-value pair object, representing an iteration. key is used as the variable name to be used in the request, and value is used as the value of the key.
json file parameterization steps:
1. Prepare the json format test data file to be used;
2. In the postman script, use { in HTTP requests { key }} to quote, use data. key or data["key"] in script to quote;
3. Open the Runner window, click the Select File button next to Data, and import the jsondata parameterized file; click the Data File Type to select application/json, and click the Preview button to check that the data is correct.
4. View execution results
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