Instead of rendering a reference HTML page that wraps an <img> tag
pointing to a PNG, Screenshot tests now load the expected PNG directly
from disk and compare it against the rendered screenshot. This
eliminates the indirection of loading and rendering a second page just
to display a static image.
This also means --rebaseline now works for Screenshot tests, generating
the expected PNG automatically instead of requiring manual screenshot
capture and placement.
Changes:
- Add TestMode::Screenshot with its own collector and runner
- Move PNGs from Screenshot/images/ to Screenshot/expected/ with
normalized names matching input filenames
- Remove all 92 reference HTML wrapper files and the images/
directory
- Remove <link rel="match"> from all 94 Screenshot input HTML
files
- Update add_libweb_test.py Screenshot boilerplate accordingly
- Add Screenshot mode to results viewer image comparison tabs
If the difference between the expected and actual test images was small,
our in-browser diff tool would often fail to highlight differing pixels.
Replace this by generating a new diff PNG that is layered as follows:
1. 50%/50% blend of the actual and expected images
2. 80% blend with white / rgb(255, 255, 255)
3. Differing pixels are highlighted in red / rgb(255, 0, 0)
- Generate colorized HTML diff files (.diff.html) alongside plain text
diffs (.diff.txt) for each failing test
- Add total test count to results summary
- Improve the results-index.html viewer with a dark theme, keyboard
navigation, search/filter, and tabbed interface for viewing diffs,
expected/actual output, and stdout/stderr
- Move s_total_tests assignment outside live display block so it's
always set
- Add --results-dir CLI flag to specify output directory
- Default to {tempdir}/test-web-results if not specified
- Capture stdout/stderr from all helper processes (WebContent,
RequestServer, ImageDecoder) to prevent output spam
- Save captured output to per-test files in results directory
- Save test diffs (expected vs actual) to results directory
- Generate HTML index of failed tests with links to diffs
- Display live-updating concurrent test status with progress bar
- Defer warning messages until after test run completes
