Tutorial: Develop a simple IDT test suite - AWS IoT Greengrass

AWS IoT Greengrass Version 1 no longer receives feature updates, and will receive only security patches and bug fixes until June 30, 2023. For more information, see the AWS IoT Greengrass V1 maintenance policy. We strongly recommend that you migrate to AWS IoT Greengrass Version 2, which adds significant new features and support for additional platforms.

Tutorial: Develop a simple IDT test suite

A test suite combines the following:

  • Test executables that contain the test logic

  • JSON configuration files that describe the test suite

This tutorial shows you how to use IDT for AWS IoT Greengrass to develop a Python test suite that contains a single test case. In this tutorial, you will complete the following steps:

Prerequisites

To complete this tutorial, you need the following:

  • Host computer requirements

    • Latest version of AWS IoT Device Tester

    • Python 3.7 or later

      To check the version of Python installed on your computer, run the following command:

      python3 --version

      On Windows, if using this command returns an error, then use python --version instead. If the returned version number is 3.7 or greater, then run the following command in a Powershell terminal to set python3 as an alias for your python command.

      Set-Alias -Name "python3" -Value "python"

      If no version information is returned or if the version number is less than 3.7, follow the instructions in Downloading Python to install Python 3.7+. For more information, see the Python documentation.

    • urllib3

      To verify that urllib3 is installed correctly, run the following command:

      python3 -c 'import urllib3'

      If urllib3 is not installed, run the following command to install it:

      python3 -m pip install urllib3
  • Device requirements

    • A device with a Linux operating system and a network connection to the same network as your host computer.

      We recommend that you use a Raspberry Pi with Raspberry Pi OS. Make sure you set up SSH on your Raspberry Pi to remotely connect to it.

Create a test suite directory

IDT logically separates test cases into test groups within each test suite. Each test case must be inside a test group. For this tutorial, create a folder called MyTestSuite_1.0.0 and create the following directory tree within this folder:

MyTestSuite_1.0.0 └── suite └── myTestGroup └── myTestCase

Create JSON configuration files

Your test suite must contain the following required JSON configuration files:

Required JSON files

suite.json

Contains information about the test suite. See Configure suite.json.

group.json

Contains information about a test group. You must create a group.json file for each test group in your test suite. See Configure group.json.

test.json

Contains information about a test case. You must create a test.json file for each test case in your test suite. See Configure test.json.

  1. In the MyTestSuite_1.0.0/suite folder, create a suite.json file with the following structure:

    { "id": "MyTestSuite_1.0.0", "title": "My Test Suite", "details": "This is my test suite.", "userDataRequired": false }
  2. In the MyTestSuite_1.0.0/myTestGroup folder, create a group.json file with the following structure:

    { "id": "MyTestGroup", "title": "My Test Group", "details": "This is my test group.", "optional": false }
  3. In the MyTestSuite_1.0.0/myTestGroup/myTestCase folder, create a test.json file with the following structure:

    { "id": "MyTestCase", "title": "My Test Case", "details": "This is my test case.", "execution": { "timeout": 300000, "linux": { "cmd": "python3", "args": [ "myTestCase.py" ] }, "mac": { "cmd": "python3", "args": [ "myTestCase.py" ] }, "win": { "cmd": "python3", "args": [ "myTestCase.py" ] } } }

The directory tree for your MyTestSuite_1.0.0 folder should now look like the following:

MyTestSuite_1.0.0 └── suite ├── suite.json └── myTestGroup ├── group.json └── myTestCase └── test.json

Get the IDT client SDK

You use the IDT client SDK to enable IDT to interact with the device under test and to report test results. For this tutorial, you will use the Python version of the SDK.

From the <device-tester-extract-location>/sdks/python/ folder, copy the idt_client folder to your MyTestSuite_1.0.0/suite/myTestGroup/myTestCase folder.

To verify that the SDK was successfully copied, run the following command.

cd MyTestSuite_1.0.0/suite/myTestGroup/myTestCase python3 -c 'import idt_client'

Create the test case executable

Test case executables contain the test logic that you want to run. A test suite can contain multiple test case executables. For this tutorial, you will create only one test case executable.

  1. Create the test suite file.

    In the MyTestSuite_1.0.0/suite/myTestGroup/myTestCase folder, create a myTestCase.py file with the following content:

    from idt_client import * def main(): # Use the client SDK to communicate with IDT client = Client() if __name__ == "__main__": main()
  2. Use client SDK functions to add the following test logic to your myTestCase.py file:

    1. Run an SSH command on the device under test.

      from idt_client import * def main(): # Use the client SDK to communicate with IDT client = Client() # Create an execute on device request exec_req = ExecuteOnDeviceRequest(ExecuteOnDeviceCommand("echo 'hello world'")) # Run the command exec_resp = client.execute_on_device(exec_req) # Print the standard output print(exec_resp.stdout) if __name__ == "__main__": main()
    2. Send the test result to IDT.

      from idt_client import * def main(): # Use the client SDK to communicate with IDT client = Client() # Create an execute on device request exec_req = ExecuteOnDeviceRequest(ExecuteOnDeviceCommand("echo 'hello world'")) # Run the command exec_resp = client.execute_on_device(exec_req) # Print the standard output print(exec_resp.stdout) # Create a send result request sr_req = SendResultRequest(TestResult(passed=True)) # Send the result client.send_result(sr_req) if __name__ == "__main__": main()

Configure device information for IDT

Configure your device information for IDT to run the test. You must update the device.json template located in the <device-tester-extract-location>/configs folder with the following information.

[ { "id": "pool", "sku": "N/A", "devices": [ { "id": "<device-id>", "connectivity": { "protocol": "ssh", "ip": "<ip-address>", "port": "<port>", "auth": { "method": "pki | password", "credentials": { "user": "<user-name>", "privKeyPath": "/path/to/private/key", "password": "<password>" } } } } ] } ]

In the devices object, provide the following information:

id

A user-defined unique identifier for your device.

connectivity.ip

The IP address of your device.

connectivity.port

Optional. The port number to use for SSH connections to your device.

connectivity.auth

Authentication information for the connection.

This property applies only if connectivity.protocol is set to ssh.

connectivity.auth.method

The authentication method used to access a device over the given connectivity protocol.

Supported values are:

  • pki

  • password

connectivity.auth.credentials

The credentials used for authentication.

connectivity.auth.credentials.user

The user name used to sign in to your device.

connectivity.auth.credentials.privKeyPath

The full path to the private key used to sign in to your device.

This value applies only if connectivity.auth.method is set to pki.

devices.connectivity.auth.credentials.password

The password used for signing in to your device.

This value applies only if connectivity.auth.method is set to password.

Note

Specify privKeyPath only if method is set to pki.

Specify password only if method is set to password.

Run the test suite

After you create your test suite, you want to make sure that it functions as expected. Complete the following steps to run the test suite with your existing device pool to do so.

  1. Copy your MyTestSuite_1.0.0 folder into <device-tester-extract-location>/tests.

  2. Run the following commands:

    cd <device-tester-extract-location>/bin ./devicetester_[linux | mac | win_x86-64] run-suite --suite-id MyTestSuite

IDT runs your test suite and streams the results to the console. When the test has finished running, you see the following information:

time="2020-10-19T09:24:47-07:00" level=info msg=Using pool: pool time="2020-10-19T09:24:47-07:00" level=info msg=Using test suite "MyTestSuite_1.0.0" for execution time="2020-10-19T09:24:47-07:00" level=info msg=b'hello world\n' suiteId=MyTestSuite groupId=myTestGroup testCaseId=myTestCase deviceId=my-device executionId=9a52f362-1227-11eb-86c9-8c8590419f30 time="2020-10-19T09:24:47-07:00" level=info msg=All tests finished. executionId=9a52f362-1227-11eb-86c9-8c8590419f30 time="2020-10-19T09:24:48-07:00" level=info msg= ========== Test Summary ========== Execution Time: 1s Tests Completed: 1 Tests Passed: 1 Tests Failed: 0 Tests Skipped: 0 ---------------------------------- Test Groups: myTestGroup: PASSED ---------------------------------- Path to IoT Device Tester Report: /path/to/devicetester/results/9a52f362-1227-11eb-86c9-8c8590419f30/awsiotdevicetester_report.xml Path to Test Execution Logs: /path/to/devicetester/results/9a52f362-1227-11eb-86c9-8c8590419f30/logs Path to Aggregated JUnit Report: /path/to/devicetester/results/9a52f362-1227-11eb-86c9-8c8590419f30/MyTestSuite_Report.xml

Troubleshooting

Use the following information to help resolve any issues with completing the tutorial.

Test case does not run successfully

If the test does not run successfully, IDT streams the error logs to the console that can help you troubleshoot the test run. Before you check the error logs, verify the following:

  • The IDT client SDK is in the correct folder as described in this step.

  • You meet all the prerequisites for this tutorial.

Cannot connect to the device under test

Verify the following:

  • Your device.json file contains the correct IP address, port, and authentication information.

  • You can connect to your device over SSH from your host computer.