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 track_coverage() 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
  • 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

Requires Python 3.11+

pip install ui-coverage-tool

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 two popular UI automation frameworks: Playwright and Selenium. In both cases, coverage data is automatically saved to the ./coverage-results folder after each call to track_coverage.

Playwright

from playwright.sync_api import sync_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.)
from ui_coverage_tool import UICoverageTracker, SelectorType, ActionType

# Create an instance of the tracker.
# The `app` value should match the name in your UI_COVERAGE_APPS config.
tracker = UICoverageTracker(app="my-ui-app")

with sync_playwright() as playwright:
    browser = playwright.chromium.launch()
    page = browser.new_page()
    page.goto("https://my-ui-app.com/login")

    username_input = page.locator("#username-input")
    username_input.fill('user@example.com')

    # Track this interaction with the tracker
    tracker.track_coverage(
        selector='#username-input',  # The selector (CSS)
        action_type=ActionType.FILL,  # The action type: FILL
        selector_type=SelectorType.CSS  # The selector type: CSS
    )

    login_button = page.locator('//button[@id="login-button"]')
    login_button.click()

    # Track the click action with the tracker
    tracker.track_coverage(
        selector='//button[@id="login-button"]',  # The selector (XPath)
        action_type=ActionType.CLICK,  # The action type: CLICK
        selector_type=SelectorType.XPATH  # The selector type: XPath
    )

Quick summary:

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

Selenium

from selenium import webdriver
from ui_coverage_tool import UICoverageTracker, SelectorType, ActionType

driver = webdriver.Chrome()

# Initialize the tracker with the app key
tracker = UICoverageTracker(app="my-ui-app")

driver.get("https://my-ui-app.com/login")

username_input = driver.find_element("css selector", "#username-input")
username_input.send_keys("user@example.com")

# Track the fill action
tracker.track_coverage('#username-input', ActionType.FILL, SelectorType.CSS)

login_button = driver.find_element("xpath", '//button[@id="login-button"]')
login_button.click()

# Track the click action
tracker.track_coverage('//button[@id="login-button"]', ActionType.CLICK, SelectorType.XPATH)

Coverage Report Generation

After every call to tracker.track_coverage(...), 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:

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 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 get_settings().

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"

results_dir: "./coverage-results"
history_file: "./coverage-history.json"
history_retention_limit: 30
html_report_file: "./index.html"
json_report_file: "./coverage-report.json"

Configuration via JSON

Example: ui_coverage_config.json

{
  "services": [
    {
      "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"
    }
  ],
  "results_dir": "./coverage-results",
  "history_file": "./coverage-history.json",
  "history_retention_limit": 30,
  "html_report_file": "./index.html",
  "json_report_file": "./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).	❌	—
results_dir	Directory to store raw coverage result files.	❌	./coverage-results
history_file	File to store historical coverage data.	❌	./coverage-history.json
history_retention_limit	Maximum number of historical entries to keep.	❌	30
html_report_file	Path to save the final HTML report (if enabled).	❌	./index.html
json_report_file	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:

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: copy-report

This is an internal command mainly used during local development. It updates the report template for the generated coverage reports. It is typically used to ensure that the latest report template is available when you generate new reports.

Usage:

ui-coverage-tool copy-report

• This command updates the internal template used by the save-report command. It's useful if the template structure or styling has changed and you need the latest version for your reports.
• This command is typically only used by developers working on the tool itself.

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:

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