feat: Add assert_screenshot/3 for visual regression testing#181
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Thank you so much for this Wígny!
An excellent addition to phoenix_test_playwright, and two well crafted PRs.
Some small comments.
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Handle renamed error key `custom_error_message` (was `error_message`) in the `expect_screenshot` wire format introduced in playwright_ex 0.7.0.
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Thanks for the changes.
Especially the improvements to documentation is appreciated.
That made me think we should be more consistent regarding defaults:
Either duplicate all, or remove all defaults (and rely on playwright defaults).
Also, if you don't mind: Copy option doc text from playwright docs?
Happy to merge as is though.
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Beautiful. Let's get this baby shipped. |
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When writing browser tests, we sometimes need to assert visual changes in elements — layout shifts, style regressions, rendering differences.
@playwright/testshipstoHaveScreenshotfor exactly this, but it's not accessible from Elixir.This PR introduces
assert_screenshot/3, a helper built on the same underlying PlaywrightexpectScreenshotprotocol command that powerstoHaveScreenshot.On the first run, it captures a screenshot and saves it as the baseline. On subsequent runs, it compares the live page against that baseline server-side, passing silently on match, failing with a diff image on mismatch.
Note: depends on ftes/playwright_ex#56. The
mix.exspoints at that branch and will need updating once it merges.