UI Coverage Tool

UI Coverage Tool is an innovative, no-overhead solution for tracking and visualizing UI test coverage — directly on your actual application, not static snapshots. The tool collects coverage during UI test execution and generates an interactive HTML report. This report embeds a live iframe of your application and overlays coverage data on top, letting you see exactly what was tested and how.

Features

• Live application preview: The report displays a real iframe of your app, not static screenshots. You can explore any page and see which elements were interacted with, what actions were performed, and how often.
• Flexible frame filters: Focus only on what matters — filter elements by specific actions (CLICK, FILL, VISIBLE, etc.), or action groups. Ideal for analyzing specific scenarios or regression areas.
• Custom highlight & badge colors: Easily change the highlight and badge colors used in the iframe for different action types or UI states. Great for tailoring the report to your team's visual style or accessibility needs.
• No framework lock-in: Works with any UI testing framework (Playwright, Selenium, etc.) by simply logging actions via the trackCoverage() method.
• Element-level statistics: View detailed statistics by selector: type of action, count of actions, and a timeline graph of coverage.
• Global history overview: Track historical trends of total coverage and action types across time.
• Per-element timeline: Dive deep into the history of interactions for each element — when and how it was used.
• Full element index: Searchable table of all elements interacted with during tests, even if you're not sure where they are in the UI.
• Multi-app support: Testing multiple domains? No problem. Just list your apps in the config — the report will let you switch between them.

Table of Contents

• Features
• Links
• Preview
• Installation
• Embedding the Agent Script
• Usage
  • Playwright
  • Selenium
  • Puppeteer
  • Coverage Report Generation
• Configuration
  • .env
  • YAML
  • JSON
  • Reference
• Command-Line Interface (CLI)

Links

Example Report

You can view an example of a coverage report generated by the tool here.

Questions & Support

If you have any questions or need assistance, feel free to ask @Nikita Filonov.

Preview

Summary

History

Frame

Element Details

Elements Table

Installation

With npm

npm install ui-coverage-tool-js

With yarn

yarn add ui-coverage-tool-js

Embedding the Agent Script

To enable live interaction and visual highlighting in the report, you must embed the coverage agent into your application.

Add this to your HTML:

<script src="https://nikita-filonov.github.io/ui-coverage-report/agent.global.js"></script>

That’s it. No other setup required. Without this script, the coverage report will not be able to highlight elements.

Usage

Below are examples of how to use the tool with popular UI automation frameworks: Playwright, Puppeteer, Selenium. In both cases, coverage data is automatically saved to the ./coverage-results folder after each call to await tracker.trackCoverage(...).

Playwright

import { chromium } from 'playwright';
// Import the main components of the tool:
// - UICoverageTracker — the main class for tracking coverage
// - SelectorType — type of selector (CSS, XPATH)
// - ActionType — type of action (CLICK, FILL, CHECK_VISIBLE, etc.)
import { ActionType, SelectorType, UICoverageTracker } from 'ui-coverage-tool-js';

// Create an instance of the tracker.
// The `app` value should match the name in your UI_COVERAGE_APPS config.
const tracker = new UICoverageTracker({ app: 'my-ui-app' });

(async () => {
  const browser = await chromium.launch();
  const page = await browser.newPage();

  await page.goto('https://my-ui-app.com/login');

  const usernameInput = page.locator('#username-input');
  await usernameInput.fill('user@example.com');

  // Track this interaction with the tracker
  await tracker.trackCoverage({
    selector: '#username-input',
    selectorType: SelectorType.CSS,
    actionType: ActionType.FILL
  });

  const loginButton = page.locator('//button[@id="login-button"]');
  await loginButton.click();

  // Track the click action with the tracker
  await tracker.trackCoverage({
    selector: '//button[@id="login-button"]',
    selectorType: SelectorType.XPATH,
    actionType: ActionType.CLICK
  });

  await browser.close();
})();

Quick summary:

• Call await tracker.trackCoverage(...) after each user interaction.
• Provide the selector, action type, and selector type.
• The tool automatically stores tracking data as JSON files.

Puppeteer

import puppeteer from 'puppeteer';
import { ActionType, SelectorType, UICoverageTracker } from 'ui-coverage-tool-js';

const tracker = new UICoverageTracker({ app: 'my-ui-app' });

(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();

  await page.goto('https://my-ui-app.com/login');

  await page.type('#username-input', 'user@example.com');
  await tracker.trackCoverage({
    selector: '#username-input',
    selectorType: SelectorType.CSS,
    actionType: ActionType.FILL
  });

  const loginButton = await page.$x('//button[@id="login-button"]');
  if (loginButton[0]) {
    await loginButton[0].click();
    await tracker.trackCoverage({
      selector: '//button[@id="login-button"]',
      selectorType: SelectorType.XPATH,
      actionType: ActionType.CLICK
    });
  }

  await browser.close();
})();

Selenium

import { Builder, By } from 'selenium-webdriver';
import { ActionType, SelectorType, UICoverageTracker } from 'ui-coverage-tool-js';

const tracker = new UICoverageTracker({ app: 'my-ui-app' });

(async () => {
  const driver = await new Builder().forBrowser('chrome').build();

  try {
    await driver.get('https://my-ui-app.com/login');

    const usernameInput = await driver.findElement(By.css('#username-input'));
    await usernameInput.sendKeys('user@example.com');

    await tracker.trackCoverage({
      selector: '#username-input',
      actionType: ActionType.FILL,
      selectorType: SelectorType.CSS
    });

    const loginButton = await driver.findElement(By.xpath('//button[@id="login-button"]'));
    await loginButton.click();

    await tracker.trackCoverage({
      selector: '//button[@id="login-button"]',
      actionType: ActionType.CLICK,
      selectorType: SelectorType.XPATH
    });

  } finally {
    await driver.quit();
  }
})();

Coverage Report Generation

After every call to await tracker.trackCoverage(...), the tool automatically stores coverage data in the ./coverage-results/ directory as JSON files. You don’t need to manually manage the folder — it’s created and populated automatically.

./coverage-results/
  ├── 0a8b92e9-66e1-4c04-aa48-9c8ee28b99fa.json
  ├── 0a235af0-67ae-4b62-a034-a0f551c9ebb5.json
  └── ...

Once your tests are complete and coverage data has been collected, generate a final interactive report using this command:

npx ui-coverage-tool save-report

This will generate:

• index.html — a standalone HTML report that you can:
  • Open directly in your browser
  • Share with your team
  • Publish to GitHub Pages / GitLab Pages
• coverage-report.json — a structured JSON report that can be used for:
  • Printing a coverage summary in CI/CD logs
  • Sending metrics to external systems
  • Custom integrations or dashboards

Important! The npx ui-coverage-tool save-report command must be run from the root of your project, where your config files (.env, ui-coverage.config.yaml, etc.) are located. Running it from another directory may result in missing data or an empty report.

Configuration

You can configure the UI Coverage Tool using a single file: either a YAML, JSON, or .env file. By default, the tool looks for configuration in:

• ui-coverage.config.yaml
• ui-coverage.config.json
• .env (for environment variable configuration)

All paths are relative to the current working directory, and configuration is automatically loaded via getSettings().

Important! Files must be in the project root.

Configuration via .env

All settings can be declared using environment variables. Nested fields use dot notation, and all variables must be prefixed with UI_COVERAGE_.

Example: .env

# Define the applications that should be tracked. In the case of multiple apps, they can be added in a comma-separated list.
UI_COVERAGE_APPS='[
    {
        "key": "my-ui-app",
        "url": "https://my-ui-app.com/login",
        "name": "My UI App",
        "tags": ["UI", "PRODUCTION"],
        "repository": "https://github.com/my-ui-app"
    }
]'

# The directory where the coverage results will be saved.
UI_COVERAGE_RESULTS_DIR="./coverage-results"

# The file that stores the history of coverage results.
UI_COVERAGE_HISTORY_FILE="./coverage-history.json"

# The retention limit for the coverage history. It controls how many historical results to keep.
UI_COVERAGE_HISTORY_RETENTION_LIMIT=30

# Optional file paths for the HTML and JSON reports.
UI_COVERAGE_HTML_REPORT_FILE="./index.html"
UI_COVERAGE_JSON_REPORT_FILE="./coverage-report.json"

Configuration via YAML

Example: ui-coverage.config.yaml

apps:
  - key: "my-ui-app"
    url: "https://my-ui-app.com/login",
    name: "My UI App"
    tags: [ "UI", "PRODUCTION" ]
    repository: "https://github.com/my-ui-app"

resultsDir: "./coverage-results"
historyFile: "./coverage-history.json"
historyRetentionLimit: 30
htmlReportFile: "./index.html"
jsonReportFile: "./coverage-report.json"

Configuration via JSON

Example: ui-coverage.config.json

{
  "apps": [
    {
      "key": "my-ui-app",
      "url": "https://my-ui-app.com/login",
      "name": "My UI App",
      "tags": [
        "UI",
        "PRODUCTION"
      ],
      "repository": "https://github.com/my-ui-app"
    }
  ],
  "resultsDir": "./coverage-results",
  "historyFile": "./coverage-history.json",
  "historyRetentionLimit": 30,
  "htmlReportFile": "./index.html",
  "jsonReportFile": "./coverage-report.json"
}

Configuration Reference

Key	Description	Required	Default
apps	List of applications to track. Each must define key, name, and url.	✅	—
services[].key	Unique internal identifier for the service.	✅	—
services[].url	Entry point URL of the app.	✅	—
services[].name	Human-friendly name for the service (used in reports).	✅	—
services[].tags	Optional tags used in reports for filtering or grouping.	❌	—
services[].repository	Optional repository URL (will be shown in report).	❌	—
resultsDir	Directory to store raw coverage result files.	❌	./coverage-results
historyFile	File to store historical coverage data.	❌	./coverage-history.json
historyRetentionlimit	Maximum number of historical entries to keep.	❌	30
htmlReportFile	Path to save the final HTML report (if enabled).	❌	./index.html
jsonReportFile	Path to save the raw JSON report (if enabled).	❌	./coverage-report.json

How It Works

Once configured, the tool automatically:

• Tracks test coverage during UI interactions.
• Writes raw coverage data to coverage-results/.
• Stores optional historical data and generates an HTML report at the end.

No manual data manipulation is required – the tool handles everything automatically based on your config.

Command-Line Interface (CLI)

The UI Coverage Tool provides several CLI commands to help with managing and generating coverage reports.

Command: save-report

Generates a detailed coverage report based on the collected result files. This command will process all the raw coverage data stored in the coverage-results directory and generate an HTML report.

Usage:

npx ui-coverage-tool save-report

• This is the main command to generate a coverage report. After executing UI tests and collecting coverage data, use this command to aggregate the results into a final report.
• The report is saved as an HTML file, typically named index.html, which can be opened in any browser.

Command: print-config

Prints the resolved configuration to the console. This can be useful for debugging or verifying that the configuration file has been loaded and parsed correctly.

Usage:

npx ui-coverage-tool print-config

• This command reads the configuration file (ui-coverage.config.yaml, ui-coverage.config.json, or .env) and prints the final configuration values to the console.
• It helps verify that the correct settings are being applied and is particularly useful if something is not working as expected.

Troubleshooting

The report is empty or missing data

• Ensure that trackCoverage() is called during your tests.
• Make sure you run npx ui-coverage-tool save-report from the root directory.
• Make sure to setup configuration correctly.
• Check that the coverage-results directory contains .json files.