!oaklean-header

@oaklean/jest-profiler-environment

A jest environment to collect energy measurements on source code level during test execution.

Supports Jest versions 28 & 29.

Table of Contents

- Usage
- Installation
- Configure Jest
- Configure Oaklean
- Collect Energy Measurements
- Interpret The Measurements
- For More Information

Usage

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npm add --save-dev @oaklean/profiler-jest-environment

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Add the @oaklean/jest-profiler-environment to the jest config:

Adjust the jest config like this:
``javascript
module.exports = {
...
testEnvironment: '@oaklean/profiler-jest-environment/env.js', // add this line
globalSetup: '@oaklean/profiler-jest-environment/setup.js', // add this line
globalTeardown: '@oaklean/profiler-jest-environment/teardown.js', // add this line
...
}
`

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The CLI can be used to easily setup a .oaklean config file.
1. Install oaklean: npm add @oaklean/profiler
2. Run the init script: npx oak init
3. It will ask you which sensor interface should be used for energy measurements:
`
Select a sensor interface (recommended for your platform: perf)
None (pure cpu time measurements)
powermetrics (macOS only)
❯ perf (Linux only)
windows (Windows only)
energy measurements on Linux (Intel & AMD CPUs only)
`
4. The cli asks you to confirm your choice and generates a valid .oaklean and .oaklean.local config file for you:
`
✔ Select a sensor interface (recommended for your platform: powermetrics) perf (Linux only)
[Oaklean] [Main Config]
{
"extends": ".oaklean.local",
"exportOptions": {
"outDir": "profiles/",
"outHistoryDir": "profiles_history/",
"rootDir": "./",
"exportV8Profile": false,
"exportReport": true,
"exportSensorInterfaceData": false
},
"projectOptions": {
"identifier": "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX"
},
"runtimeOptions": {
"seeds": {},
"v8": {
"cpu": {
"sampleInterval": 1
}
}
}
}
[Oaklean] [Local Config]
{
"runtimeOptions": {
"sensorInterface": {
"type": "perf",
"options": {
"outputFilePath": "energy-measurements.txt",
"sampleInterval": 100
}
}
}
}
? Is this OK? (yes) (Y/n)
`

##### Available Sensor Interfaces
| SensorInterface | Operating System |
| --------------- | ---------------- |
| powermetrics | macOS |
| perf | linux |
| windows | windows |

If you want to how to setup the Sensor Interfaces and how to make them work with Docker you can read more about it here

> :warning: Most Sensor Interfaces need root privileges

> Look into the Sensor Interface Docs to see how you can run them without root privileges

> :mag: How measurements work

> During the test execution measurements are collected with a sample based approach. So for every n - microseconds it collects a v8 cpu profile and energy measurements of the sensor interface. You can adjust the sampling rate with the sampleInterval options in the .oaklean config file above.

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> :warning: The measurement data is NOT automatically collected

To enable measurements during test execution you must set an environment variable beforehand (ENABLE_MEASUREMENTS=1).
When running Jest tests with this environment variable, the measurement data should be saved in the specified output directory.

> :pinched_fingers: For more accurate measurement results

It is mandatory to run Jest with the --runInBand option. This ensures that the tests are executed sequentially and not in different threads: npx jest --coverage --runInBand.

Execute the tests:
ENABLE_MEASUREMENTS=1 npx jest --coverage --runInBand

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The Oaklean` VSCode Extension lets you to interpret the measurements. It integrates the energy measurements directly into your IDE.

You can find it here:
- Github
- VS Code Extension

It provides code highlighting to point out which source code locations consume the most energy:


!vscode-code-highlighting-img


It also provides multiple features to determine the components that consume the most energy, including node modules:


!vscode-explorer-img

For More Information

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* Oaklean Website

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* Oaklean Profiler
* Oaklean VS Code Extension

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* Oaklean Packages

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* Oaklean Extension - Visual Studio Marketplace
* Oaklean Extension - Open VSX Registry