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@instana/synthetic-browser-script
Advanced tools
A local runner to test and debug your browser scripts locally with CLI
This is a local runner can accelerate your Synthetic browser testing on-boarding. It provides totally the same testing results as Instana Synthetic thus can save your time in developing and testing Synthetic scripts locally. As a script writer you may have following requirements:
💡 a local runner to test and debug my scripts locally with CLI
💡 a npm package providing all the Instana Synthetic browser testing APIs
💡 "code completion" or "code hinting" in VS Code for all the browser testing APIs
💡 open full browser to perform my test actions to convince me of the quality of my scripts
💡 reproduce my test failures locally to help me debug root cause
💡 examples to demonstrate how to use browser testing APIs thus I can write my own ones on top of them
Synthetic-browser-script is now available in the public NPM channel.
Supported runtime
Chromium, Mozilla Firefox, Node.js runtime.
☑️ Google Chrome / Chromium
☑️ Mozilla Firefox
☑️ Node.js v22.x
☑️ selenium-webdriver v4.35.0
macOS and Linux are supported by default. You can skip this step if you are using macOS or Linux. To set up your environment in Windows, you can install WSL 2 and then install any Linux distribution (i.e. Ubuntu).
xeyes doesn't work: check the inbound rules for VcXsrv windows server (Windows Security - Firewall & network protection - Advanced settings - Inbound rules). Allow the traffic for TCP protocol and restrict the Scope by including only your local IP address.The rest of the steps described in this document can now be performed on your Linux distribution.
You can use nvm to install Node.js if you don't have one.
Node.js v22 is recommended.
nvm install v22.12.0
node --version
v22.12.0
# if you have multiple versions of Node.js installed, you can switch Node.js version with nvm
nvm list
nvm alias default v22.12.0
nvm use v22.12.0
Initialize a new project with default values if you don't have one.
It is recommended to create a project folder as a new Node.js project.
Then you can put all your scripts under this Node.js project or sub-folders, develop and maintain your scripts continuously.
Firstly, assuming that your project folder is browser-local-runner, you will install @instana/synthetic-browser-script package under your Node.js project as a dependency following the instructions below.
Secondly, you can put your first script in the sub-folder e.g. test-ibm-website.
Then you get all the test results in this sub-folder including screenshots, browser logs, HAR file, videos if generated after running your script with the local runner.
# create a folder for your Node.js project as your working directory
cd browser-local-runner
# use npm init to initialize
npm init
From your existing project's root dir:
# npm local install
npm install @instana/synthetic-browser-script --save-dev
# yarn local install
yarn add -D @instana/synthetic-browser-script
To run the command-line and verify the installation, use npx synb --help. Global installation is not recommended.
Synthetic-browser-script comes with useful command line options and rich examples, which are automatically copied to node_modules/@instana/synthetic-browser-script/examples during installation and can also be used as boilerplate to write your own tests on top of them.
When you use local installation, you can run the command-line application with npx synb --help.
You can run --help and follow the instructions given at the console output. Use --version or -v to ensure it is the latest version.
# list all the command-line options
npx synb --help
# check the current version
npx synb --version
Use CLI npx synb to execute.
Use -b to specify the browser type (chrome is by default without this option).
Use --isNewEngine=true flag if your chrome browser version is greater than v126.0.0.
Use -f to specify the entry point of the javascript test scripts.
# copy examples
cp -r node_modules/@instana/synthetic-browser-script/examples .
# run bundled browser test scripts
npx synb -b chrome -f examples/bundledscripts/mytest.js
Execution logs will be shown in console output. All the test results including HAR file, videos, screenshots, browser log can be found in the same directory of your test script.
Create a folder for your test scripts and use -f, --file to specify the entry point of the test scripts. The test results will be put in the same folder. Synthetic-browser-script comes with examples of different browser test types as Browser Script, Selenium IDE Script, single or bundled script in node_modules/@instana/synthetic-browser-script/examples. Will take them as examples. For the examples with proxy demonstration as examples/browserscripts/api-sample-proxy.js and examples/side/api-sample-browserapi.side, you need to change the proxy to the valid one before running it.
Example #1: Use npx synb --help to check all the CLI options.
Example #2: Execute browser script test
Instana Synthetic browser testing supports Selenium based APIs, and additional more than 30 extended browser testing APIs. Refer to Browser Testing API reference for useful browser testing APIs. The examples in examples/browserscripts demonstrate how to use these APIs. Run a demo test as below. --delay --loglevel are optional. --delay can make test fast by delaying cleanup work. --loglevel can set user log level.
npx synb -f examples/browserscripts/api-sample-actions.js --delay --loglevel error
Example #3: Execute scripts with user credentials
You can use $secure.MY_SECURE_CREDENTIAL to refer to predefined secure credentials in your script. $secure is one of the global variables Instana synthetic provided to help you accelerate and optimize script development. For more information about how to use global variables in Instana Synthetic, see Instana Browser scripts.
To test and run script locally, you can create a file of synb.json in the same directory or parent directory of your scripts to mockup global variables for test purpose.
synb.json
{
"secure": {
"username": "user1",
"password": "pass1"
}
}
npx synb -f examples/bundledscripts/mytest.js
To run test in Instana, create a credential with Instana Open API to store and access the secrets securely with the following steps:
Then, in your browser script, use $secure.credentialName to refer to the created credential, for example, $secure.username or $secure.password. You can find the complete example in test_login_2fa.js.
// mytest.js
// input email
await findElementByIdAndSendKeys('email', $secure.username, timeout);
// input password
await findElementByIdAndSendKeys('password', $secure.password, timeout);
// click login
await findButtonByClassAndClick('in-button');
Example #4: Execute multiple browser scripts with global variables
If the business logic is really complex, containing everything in a single script is a bad experiences for developers, multiple script files are also supported for better maintenance, especially managing them in Git repo. You can use bundled scripts and use -f to point the entry point.
In this example examples/bundledscripts, we use multiple scripts and $synthetic global object to demonstrate how to write complex test scripts. You can use $synthetic.var_name to access predefined or customized environment and runtime variables in the script. For more information about how to use global variables in Instana Synthetic, see Instana Browser scripts.
The $synthetic object's properties can be accessed by user scripts.
And the properties of $synthetic.labels can be defined as "customProperties" in Synthetic test configuration.
In your local test env, you can define examples/bundledscripts/synb.json to mockup these variables for test purpose.
You can also put it in parent path in your project root directory.
npx synb -f examples/bundledscripts/mytest.js
Example #5: Execute selenium IDE scripts
The easiest way to create your own scripts is to use Selenium IDE to record and Synthetic-browser-script to playback.
Download and install Selenium IDE Firefox addon or Chrome extension in Firefox/Chrome browser. Restart the browser.
Open Selenium IDE from the menu bar.
Click Record a new test in a new project link in the open-up window, and follow the instructions to record a script.
When Selenium IDE is recording, it generates a command for each user action in a script.
After recording, save the script into a .side file.
You can add commands e.g. assert title, or test your script with run button.

Test with Synthetic-browser-script.
Why can not playback with Selenium IDE directly? Instana Synthetic provides more advanced Browser Testing APIs which can not be supported by Selenium IDE. If you are using them, you can run your side script with Synthetic-browser-script. Further more, usually you have cookies or cache in your browser once you access the website, unless you clean them from browser settings, you will not see the same website pages as end users. Thus it is recommended to playback with Instana Synthetic-browser-script.
npx synb --side -f examples/side/search-instana.side
How can I set a proxy for my local test? You can use environment variables if you do not want to change your scripts.
export PLAYBACK_PROXY_TYPE="manual"
export PLAYBACK_PROXY_HOST_PORT="hostname:8080"
Then you can see the logs:
2023-05-26T05:29:22Z [SyntheticPoP] [INFO] manual proxy config {"proxyType":"manual","ftpProxy":"xxxx:8080","httpProxy":"xxxx:8080","sslProxy":"xxxxx:8080"}
After test with CLI, you can create your Synthetic test in Instana.
Instana Browser testing test types:
Use Instana Synthetic Monitoring UI to create your test by using the wizard.
You can also use synthetic-synctl tool to create Synthetic test by using command lines.
# create a WebpageScript test with Selenium IDE recorded script
synctl create test -t 3 \
--label browserscript-1 \
--location "LNCa5C1uYDYTL8hXFVps" \
--record-video true \
--frequency 15
--from-file side/webpage-script.side \
--browser chrome
# create a BrowserScript test with JavaScript file
synctl create test -t 2 \
--label "browserscript-test" \
--location "$LOCATION_ID" \
--frequency 5 \
--browser chrome \
--from-file api-sample-actions.js
# patch a Synthetic test to update test script
synctl patch test 6wY4yPKfEpz09sBFhYSG --script-file rumattatch.side
# get test details to see the updated results
synctl get test 6wY4yPKfEpz09sBFhYSG --show-details
Launch Visual Studio Code with code . in your project directory which already set up above.
You can develop your browser script tests in Visual Studio Code with "code completion" or "code hinting" feature for all the browser testing APIs.
Workspace in VS Code

VS Code IntelliSense for Browser Testing


.vscode/launch.json
{
"version": "0.2.0",
"configurations": [
{
"type": "node",
"request": "launch",
"name": "yarn start",
"runtimeExecutable": "yarn",
"runtimeArgs": ["start"],
"port": 5858,
"cwd": "${workspaceRoot}",
"timeout": 10000
}
]
}
package.json
{
"name": "browser-local-runner",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1",
"start": "synb --file examples/bundledscripts/mytest.js"
},
"author": "",
"license": "ISC",
"devDependencies": {
"@instana/synthetic-browser-script": "^1.1.0"
}
}
FAQs
A local runner to test and debug your browser scripts locally with CLI
The npm package @instana/synthetic-browser-script receives a total of 4 weekly downloads. As such, @instana/synthetic-browser-script popularity was classified as not popular.
We found that @instana/synthetic-browser-script demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 6 open source maintainers collaborating on the project.
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