Add responsive snapshot capture and CORS iframe support

[bhokaremoin]

Overview

Adds support for responsive snapshot capture, CORS iframe serialization, and cookie context capture to improve Percy snapshot fidelity and enable multi-width testing.

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Key Features

1. Responsive Snapshot Capture

Enables capturing DOM snapshots at multiple viewport widths in a single call.

• Added capture_responsive_dom() to iterate through configured widths
• Fetches width configurations from Percy CLI via get_responsive_widths()
• Supports environment variables: PERCY_RESPONSIVE_CAPTURE_MIN_HEIGHT, PERCY_RESPONSIVE_CAPTURE_RELOAD_PAGE, RESPONSIVE_CAPTURE_SLEEP_TIME

Usage:

percy_snapshot(page, "Homepage", responsiveSnapshotCapture=True, widths=[375, 768, 1280])

2. Cookie Context Capture

Snapshots now include page cookies to preserve authentication and session state.

• Modified get_serialized_dom() to capture page.context.cookies()
• DOM snapshot structure changed from string to object: {"html": "...", "cookies": [...]}

3. CORS Iframe Capture

Captures cross-origin iframe content previously inaccessible due to browser security.

• Added process_frame() to serialize cross-origin frames
• Injects Percy DOM script into each frame context
• Sequential processing to avoid Playwright thread-safety issues

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Code Changes

percy/screenshot.py:

• is_percy_enabled() → _is_percy_enabled() returns dict instead of string
• Added get_serialized_dom() with CORS iframe support
• Added responsive capture helpers
• Unified logging via log() helper

Tests:

• Added 59 test cases with 100% coverage
• New file tests/test_init.py for wrapper tests

Infrastructure:

• Added coverage enforcement (100% threshold)
• Updated Playwright 1.28.* → 1.40.*
• Updated Percy CLI to ^1.31.9-beta.5

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Breaking Changes

• DOM snapshot structure changed from string to object
• Requires Percy CLI ^1.31.9-beta.5 or higher

[Copilot]

Pull request overview

This PR enhances the Percy Playwright Python SDK’s snapshot fidelity and capabilities by adding multi-viewport (“responsive”) DOM snapshot capture, serializing cross-origin iframes, and including cookie context in snapshots. It also tightens CI quality gates by enforcing 100% coverage and updates Playwright/Percy CLI dependencies to support the new behavior.

Changes:

• Add responsive snapshot capture (capture_responsive_dom, widths config lookup, resize/reload/sleep helpers).
• Extend DOM snapshot payload to include cookies and cross-origin iframe snapshots (get_serialized_dom, process_frame).
• Add/expand tests and enforce 100% coverage in CI; bump Playwright and Percy CLI versions.

Reviewed changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
percy/screenshot.py	Implements responsive capture, cookie capture, and CORS iframe serialization; introduces CLI logging helper.
percy/__init__.py	Adds pragma: no cover handling for defensive import fallback.
tests/test_screenshot.py	Updates/expands unit and integration tests for new snapshot payload and helpers.
tests/test_init.py	Adds tests for backwards-compatible wrapper functions and version export.
requirements.txt	Updates Playwright pin to 1.40.*.
package.json	Updates @percy/cli dev dependency to ^1.31.9-beta.5.
development.txt	Adds coverage dependency for local/CI reporting.
Makefile	Adds coverage targets and enforces 100% coverage.
.github/workflows/test.yml	Runs make test-coverage in CI.
.coveragerc	Adds coverage configuration and fail-under threshold.

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[Copilot]

Pull request overview

Copilot reviewed 9 out of 10 changed files in this pull request and generated 7 comments.

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[Copilot]

@bhokaremoin I've opened a new pull request, #126, to work on those changes. Once the pull request is ready, I'll request review from you.

[Copilot]

Pull request overview

Copilot reviewed 9 out of 10 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

percy/init.py:13

• With 100% coverage enforced, only marking the except ImportError line as # pragma: no cover won’t exclude the fallback percy_snapshot() function body from coverage. In normal installs the try import succeeds, so lines 9-13 will remain uncovered and will fail coverage report --fail-under=100. Add # pragma: no cover to the fallback def/raise lines (or restructure so the whole fallback is excluded) to keep coverage deterministic.

except ImportError:  # pragma: no cover
    # This is defensive code in case percy_snapshot is not available
    def percy_snapshot(page, *a, **kw):
        raise ModuleNotFoundError(
            "[percy] `percy-playwright-python` package is not installed, "
            "please install it to use percy_snapshot command"
        )

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