Validate responses

To validate the data returned by a request, you can use thepm.response object in a test. Define tests using thepm.test function. Provide a name and function that returns a boolean (true orfalse) value to indicate if the test passed or failed. Use Chai.js BDD syntax andpm.expect in your assertions to test the response detail.

The first parameter for the.test function is a text string that appears in the test result output. Use this to identify your tests and communicate the purpose of a test to anyone viewing the results.

For example, enter the following in thePost-response tab of a request to test if the response status code is200:

pm.test("Status test",function(){    pm.response.to.have.status(200);});

SelectSend to run your request, then select theTest Results tab in the response. The tab header displays how many tests passed and how many ran in total. You can also select theFilter Results dropdown list to view the test results by type:Passed,Skipped, andFailed.

If the request returned a200 status code, the test passes. To find out what happens with a different status code, change the expected status code in your post-response script and run the request again.

Format test result messages using pm.expect

Using thepm.expect syntax gives your test result messages a different format. Experiment with the options to get the output you find most useful.

Fork theIntro to writing tests collection to import templates containing some example post-response scripts into Postman and experiment with the code.

Your code can test the requestenvironment, as in the following example:

pm.test("environment to be production",function(){    pm.expect(pm.environment.get("env")).to.equal("production");});

You can use different syntax variations to write your tests in a way that you find readable, and that suits your application and testing logic. For example:

pm.test("response should be okay to process",function(){    pm.response.to.not.be.error;    pm.response.to.have.jsonBody("");    pm.response.to.not.have.jsonBody("error");});

Your tests can validate request responses using syntax that you tailor to the response data format. For example:

pm.test("response must be valid and have a body",function(){     pm.response.to.be.ok;     pm.response.to.be.withBody;     pm.response.to.be.json;});

Test collections and folders

You can add post-response scripts to a collection, a folder, or a single request within a collection. A post-response script associated with a collection will run after every request in the collection. A post-response script associated with a folder will run after every direct child request in the folder. This enables you to reuse commonly run tests after requests. The run order for each request will be collection tests, folder tests and then request tests.

You can alsostore post-response scripts in the Package Library. This enables you to maintain commonly used scripts and tests in a single location, share them with your team, and reuse them in your internal workspaces.

Adding scripts to collections and folders enables you to test the workflows in your API project. This helps to ensure that your requests cover typical scenarios, providing a reliable experience for application users.

To add or edit collection and folder tests, select a collection or folder in the sidebar, then select theScripts > Post-response tab.

When yourun a collection, the collection runner displays the results for all tests. The test results include the response time in milliseconds and details about whether a specific request in the collection passed or failed its tests.

You can write scripts to control the order in which your requests run usingbranching and looping.

Write tests using Postbot

You can use Postman’s AI assistantPostbot to write tests for your requests. Tell Postbot what to do in natural language, and Postbot generates post-response scripts for you. Use Postbot to add a new set of tests, visualize responses, save a field from a response, or fix your existing tests.

To write tests with Postbot, do the following:

1. Open a request and selectSend so it has a response.

2. Select theScripts > Post response tab.

3. (Optional) Select code you’d like Postbot to help with.

4. SelectOpen Postbot in the code editor. You can also selectControl+Option+P orCtrl+Alt+P to open Postbot.

5. Tell Postbot what you want to do and selectEnter.

   

You can also work with Postbot in the following ways:

• Postbot can offer suggestions based on your request and the response data. Select the down arrow (↓) on your keyboard and select one of Postbot’s suggestions.

  

• Postbot understands context. Select part of a script or the response body, then tell Postbot what you want to do or change based on the selection.

  

• You can also select part of a JSON response, right-click, then selectUse Postbot. You can tell Postman to generate tests based on the selection. For example, go to a response, select a property, and ask Postbot to generate a test to verify that it exists. Or select specific values in a response and ask Postbot to visualize only that data.

  

• Postbot also powers autocomplete in the post-response script editor. If you’veenabled Postbot, you’ll see code suggestions as you type. Select theTab key to accept the suggestion. If you’ve already paid for Postbot, you get unlimited suggestions and acceptances. For everyone else, feature usage is capped at 200 suggestion acceptance events per month.

To learn more about what you can do with Postbot, go toAbout Postbot.

Add documentation to post-response scripts

Postman supports JSDoc for documenting JavaScript functions in your post-response scripts. Documentation added to your functions using JSDoc will display in a popup window when you call your functions. You can use the officialJSDoc documentation to learn how to add documentation to your post-response scripts.

The following example has documentation for thelogger function using JSDoc. The documentation explains what the function does, and defines what thedata parameter is used for and that it accepts a string data type.

/** * This function prints a string to the Postman Console. * @param {string} data - The text to print to the Postman Console. */functionlogger(data){    console.log(`Logging information to the console,${data}`)}

Debug your tests

If you’re having trouble with your tests, do the following:

• Check if there are any errors in your scripts. A red underline will highlight possible errors. Hover over the error and selectView Problem to get help. You can also check the response viewer for specific errors.
• Debug your tests usinglog statements to ensure that you are asserting on correct data.

Next steps

After writing your first tests in Postman, you can write more complex tests and use them with other Postman tools.

• For more information about what you can do with thepm object, check out some post-response scriptexamples and visit thePostman JavaScript reference.
• To learn how to use tests with Postman Monitors and check the health and performance of your API, go toMonitor health and performance of your APIs in Postman.
• To learn how toautomate your testing by integrating collection runs within your CI/CD configuration, go toIntegrate CI tools in Postman.
• For more information about storing and reusing commonly used scripts and tests, learn aboutthe Package Library in Postman.