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Postman tests tests for expertise

Below are examples of Postman tests with implemented logic where data is passed through variables, scripts and in a loop to repeat scripts by passing data (values) in some range.

Prerequisites

  1. {{base_url}} = https://jsonplaceholder.typicode.com
  2. Given GET API request for retrieving posts : {{base_url}}/posts
  3. Given GET API request for retrieving post by its ID : {{base_url}}/posts/{{id}}
  4. Goal:
    1. To make Postman script for executing API request (GET, {{base_url}}/posts/{{post_id}}) for getting data about posts by their IDs that were saved from the original request (GET, {{base_url}}/posts

Actions:

  1. Create new Environment
  2. For GET, {{base_url}}/posts request, to add for post-request script:
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    // Save the response to an environment variable
    const responseData = pm.response.json();
    // Extract all IDs from the response
    const ids = responseData.map(item => item.id);

    // Save the list of IDs and initialize the index
    pm.environment.set("ids", JSON.stringify(ids));
    pm.environment.set("currentIndex", 0);

    // Set the next request to process the first ID
    pm.execution.setNextRequest("Process Post by ID");

  1. For GET, {{base_url}}/posts/{{post_id}} request, to add for pre-request script:

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    // Retrieve the list of IDs and the current index
    const ids = JSON.parse(pm.environment.get("ids"));
    let currentIndex = pm.environment.get("currentIndex");

    // Ensure currentIndex is a valid number
    currentIndex = parseInt(currentIndex, 10);
    if (currentIndex < ids.length) {
        // Set the current post_id for the request
        pm.environment.set("post_id", ids[currentIndex]);
    } else {
        console.log("All IDs have been processed.");
        pm.execution.setNextRequest(null); // Stop execution when done
    }

  2. For GET, {{base_url}}/posts/{{post_id}} request, to add for post-request script:

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    // Increment the index after processing the current request
    let currentIndex = pm.environment.get("currentIndex");
    currentIndex = parseInt(currentIndex, 10) + 1;

    // Save the updated index
    pm.environment.set("currentIndex", currentIndex);

    // Check if there are more IDs to process
    const ids = JSON.parse(pm.environment.get("ids"));
    if (currentIndex < ids.length) {
        pm.execution.setNextRequest("Process Post by ID"); // Repeat for the next ID
    } else {
        console.log("Finished processing all IDs.");
        pm.execution.setNextRequest(null); // Stop execution
    }
  1. Execute GET, {{base_url}}/posts/{{post_id}} request as many times as needed. Added scripts help to iterate over all post_id's that retrieved from the first GET, {{base_url}}/posts/{{post_id}} request. Control process of execution by checking Postman console output