mix excessibility (Excessibility v0.15.0)

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Runs axe-core accessibility checks on HTML snapshots.

Usage

With no arguments, checks ALL existing snapshots:

mix excessibility

With arguments, runs tests first then checks NEW snapshots only:

# Run a test file
mix excessibility test/my_app_web/live/page_live_test.exs

# Run a specific test by line number
mix excessibility test/my_app_web/live/page_live_test.exs:42

# Run tests with a tag
mix excessibility --only a11y

# Run a describe block
mix excessibility test/my_test.exs:10

# Scan each snapshot at several widths (WCAG 1.4.10 Reflow only
# shows up at narrow viewports)
mix excessibility --viewports 1440x900,320x800

# Also flag interactive elements that are mostly outside the
# visible area, and page-level horizontal overflow
mix excessibility --viewports 1440x900,320x800 --check-clipping

Configuration

  • :axe_disable_rules - List of axe rule IDs to disable (default: [])
  • :viewports - List of {width, height} tuples to scan each snapshot at (default: single 1280x720 scan). Equivalent to the --viewports flag; the flag wins when both are given.
  • :check_clipping - Flag interactive elements whose visible width falls below :clipping_ratio, plus page-level horizontal overflow (default: false). Equivalent to the --check-clipping flag.
  • :clipping_ratio - Minimum visible-width ratio before an element counts as clipped (default: 0.9)
  • :excessibility_output_path - Base directory for snapshots (default: "test/excessibility")
  • :cross_snapshot_enabled? - Diff consecutive snapshots of the same test to flag content that changed without an aria-live region (default: true). Only fires on snapshots that carry capture metadata.

Prerequisites

Run mix excessibility.install first to install axe-core and Playwright via npm.