Getting Started with RESTest

This chapter will guide you through installing RESTest, understanding its basic concepts, and creating your first test.

Installation

RESTest requires Python 3.6 or later. Install it using pip:

pip install restest

To verify the installation, run:

restest --version

This should display the current version number (e.g., v2.2.1).

Basic Concepts

Before diving into creating tests, let's understand the key concepts of RESTest:

Test Files

• RESTest uses JSON files to define tests
• Each test file may contain a system section for configuration and must contain actions array for tests
• Tests are executed in sequence, from top to bottom

Actions

Actions are the building blocks of RESTest tests. Each action can be: - An HTTP request (GET, POST, PUT, PATCH, DELETE) - A control command (like section, set, include)

Variables

• RESTest can store and reuse values between requests
• Variables can be set manually or extracted from responses
• Use the %(variable_name)s syntax to reference string variables and %(variable_name)d for integers

Tests

• Each request can include tests to validate the response
• Tests can check status codes, response body, headers, and more
• Multiple test conditions can be applied to a single response

Your First Test

Let's create a simple test that verifies a public API endpoint. We'll use the JSONPlaceholder API as an example.

Create a file named first-test.json:

{
    "system": {
        "base_url": "https://jsonplaceholder.typicode.com",
        "log_file": "./restest-first.log"
    },
    "actions": [
        {
            "title": "Get a user",
            "method": "get",
            "url": "/users/1",
            "auth": false,
            "tests": [
                {
                    "field": "name",
                    "value": "Leanne Graham"
                },
                {
                    "field": "email",
                    "value": "Sincere@april.biz"
                }
            ],
            "fields": [
                ["id", "user_id"],
                ["username", "user_name"]
            ]
        },
        {
            "title": "Get user's posts",
            "method": "get",
            "url": "/users/%(user_id)s/posts",
            "auth": false,
            "tests": [
                {
                    "field": "[0].userId",
                    "value": %(user_id)d
                },
                {
                    "field": "[]",
                    "mode": "SIZE-GT",
                    "value": 1
                }
            ]
        }
    ]
}

Let's break down this test file:

System Configuration

"system": {
    "base_url": "https://jsonplaceholder.typicode.com",
    "log_file": "./restest-first.log"
}

- base_url: The API's base URL - log_file: Where RESTest will save detailed logs

First Action: Get User

{
    "title": "Get a user",
    "method": "get",
    "url": "/users/1",
    "auth": false,
    "tests": [
        {
            "field": "name",
            "value": "Leanne Graham"
        }
    ],
    "fields": [
        ["id", "user_id"],
        ["username", "user_name"]
    ]
}

- title: Description of the test (optional but recommended) - method: HTTP method to use - auth: Whether authentication is required - tests: Validates the response - fields: Extracts values for later use

Second Action: Get Posts

{
    "title": "Get user's posts",
    "method": "get",
    "url": "/users/%(user_id)s/posts",
    "auth": false,
    "tests": [
        {
            "field": "[0].userId",
            "value": %(user_id)d
        },
        {
            "field": "[]",
            "mode": "SIZE-GT",
            "value": 0
        }
    ]
}

- Uses %(user_id)d from the previous request - Tests array elements using [0] notation - The whole array returned as response is checked using [] - Validates array size using SIZE-GT mode

Running the Test

Run the test using:

restest first-test.json

You should see output similar to:

Get a user
      GET  /users/1                                {} auth: False size:   292 - status: 200 - t: 523 ms / 0.523 s

Get user's posts
      GET  /users/1/posts                          {} auth: False size:  2.7KB - status: 200 - t: 245 ms / 0.245 s

===== FINISHED. Total Errors: 0 / 4 [Total time: 0.768000]

Understanding the Output

• Each request shows the method, URL, and parameters
• Response size and status code are displayed
• Request timing is shown in milliseconds and seconds
• Final summary shows total tests and errors

Next Steps

Now that you've created your first test, you can: 1. Explore more complex test scenarios 2. Learn about different test modes 3. Use variables and data extraction 4. Organize tests into sections

These topics will be covered in detail in the following chapters.

Common Issues

Base URL Problems

If you get connection errors, verify: - The base_url is correct - You have internet access - The API is accessible from your location

JSON Syntax

If RESTest fails to parse your file: - Validate your JSON syntax (use a JSON validator) - Check for missing commas or brackets - Ensure all strings are properly quoted

Test Failures

If tests fail: - Check the log file for detailed response data - Verify your test conditions match the actual response - Ensure variables are properly referenced

Command Line Tips

Some useful command-line options for beginners:

# Override base URL
restest --base-url https://api.example.com test.json

# Don't stop on test failures
restest --dont-stop-on-error test.json

# Show detailed curl commands
restest --curl test.json

# Clean log file before starting
restest --log-clean test.json