This patch implements a new image comparison function, codenamed
"ssim-cie94". The goal of the new comparison function is to cancel out
browser non-determenistic rendering.
To use the new comparison function:
```ts
await expect(page).toHaveScreenshot({
comparator: 'ssim-cie94',
});
```
As of Nov 30, 2022, we identified the following sources of
non-determenistic rendering for Chromium:
- Anti-aliasing for certain shapes might be different due to the
way skia rasterizes certain shapes.
- Color blending might be different on `x86` and `aarch64`
architectures.
The new function employs a few heuristics to fight these
differences.
Consider two non-equal image pixels `(r1, g1, b1)` and `(r2, g2, b2)`:
1. If the [CIE94] metric is less then 1.0, then we consider these pixels
**EQUAL**. (The value `1.0` is the [just-noticeable difference] for
[CIE94].). Otherwise, proceed to next step.
1. If all the 8 neighbors of the first pixel match its color, or
if the 8 neighbors of the second pixel match its color, then these
pixels are **DIFFERENT**. (In case of anti-aliasing, some of the
direct neighbors have to be blended up or down.) Otherwise, proceed
to next step.
1. If SSIM in some locality around the different pixels is more than
0.99, then consider this pixels to be **EQUAL**. Otherwise, mark them
as **DIFFERENT**. (Local SSIM for anti-aliased pixels turns out to be
very close to 1.0).
[CIE94]: https://en.wikipedia.org/wiki/Color_difference#CIE94
[just-noticeable difference]:
https://en.wikipedia.org/wiki/Just-noticeable_difference
This patch adds support to multiple diffs. These are possible
due to soft assertions.
Drive-by: rename second screenshot in `toHaveScreenshot` failure when
re-generating expectations from "expected" to "previous".
This patch reverts 2 commits that removed the feature from the method:
- "fix: explicitly ignore maxDiffPixels in toMatchSnapshot (#12570)"
commit b8af8458d6.
- "chore: remove `maxDiffPixels` from toMatchSnapshot (#12539)"
commit a3dff45974.
- `stdout.isTTY` controls whether list reporter updates lines or just adds them;
- `env.CI` is used in a few places to affect the defaults:
- whether to open interactive html;
- default reporter dot/line;
- default terminal reporter added to non-terminal reporters;
- `env.PWTEST_SKIP_TEST_OUTPUT` is removed;
- `env.PW_TEST_DEBUG_REPORTERS` is introduced specifically for tests.
This patch prepares for the `toHaveScreenshot` implementation
by splitting common parts from `toMatchSnapshot`.
Drive-by: fix default extension generation from `.bin` to `.dat`
for unknown buffers.
This patch adds additional options to `toMatchSnapshot` method:
- `pixelCount` - acceptable number of pixels that differ to still
consider images equal. Unset by default.
- `pixelRatio` - acceptable ratio of all image pixels (from 0 to 1) that differ to still
consider images equal. Unset by default.
Fixes#12167, #10219
Soft expects will still fail the test, but will not abort it's execution. As a consequence of this:
- `TestResult` now might have multiple errors, which is reflected with a new `testResult.erros: TestError[]` field.
- `TestInfo` now might have multiple errors as well, which is reflected with a new `testInfo.errors: TestError[]` field.
Fixes#7819
Textual snapshot diffs were previously broken in the HTML Report. The strikethrough'd text extended beyond the intended region.
HTML Report Before:
<img width="693" alt="Screen Shot 2021-12-27 at 4 43 35 PM" src="https://user-images.githubusercontent.com/11915034/147518750-a60f9002-6eed-48a1-a412-20fabd076fa6.png">
HTML Report After:
<img width="206" alt="Screen Shot 2021-12-27 at 4 48 37 PM" src="https://user-images.githubusercontent.com/11915034/147518762-19a4c8f9-ccc3-4a3c-a962-5a42edc6fc5d.png">
This now matches what's expected and shown in the terminal (which has always been correct):
<img width="1384" alt="Screen Shot 2021-12-27 at 4 36 29 PM" src="https://user-images.githubusercontent.com/11915034/147518799-f538259e-5a45-4d6f-916c-a12ccb620c5b.png">
NB: This MR is a workaround, but not a root cause fix. It works, but I never fully got to the root cause so a bug upstream may be required. It's unclear whether it's (1) in [`colors`](https://www.npmjs.com/package/colors), (2) in [`ansi-to-html`](https://www.npmjs.com/package/ansi-to-html), or (3) Playwright's use of the two. Since the terminal output is correct, I suspect it is in `ansi-to-html`. For example:
```js
const colors = require("colors");
const Convert = require('ansi-to-html');
const convert = new Convert();
// original (strike incorrectly wraps everything in the HTML)
console.log(convert.toHtml(colors.strikethrough("crossed out") + ' ' + colors.red("red")))
// prints: <strike>crossed out <span style="color:#A00">red<span style="color:#FFF"></span></span></strike>
// workaround
console.log(convert.toHtml(colors.reset(colors.strikethrough("crossed out")) + ' ' + colors.red("red")))
// prints: <strike>crossed out</strike> <span style="color:#A00">red<span style="color:#FFF"></span></span>
```
Fixes#11116
This prevents future retries from passing because of the actual
snapshot being written.
In theory, we can avoid running the retry since it should fail anyway.
However, this brings problems, for example in the `describe.serial` mode
where running a test also has some side effects and so it should not be
skipped. Since running a test without a snapshot is rare, it should be
fine to retry it.
- Uses some auto fixtures to set default options and instrumentation on BrowserType.
- Moves screenshot, trace and video to worker-scoped fixtures.
- Throws in page/context when used from beforeAll/afterAll.
- Plumbs around BrowserType to be accessible from Browser and BrowserContext.
This avoids problems with `toMatchSnapshot('../../dir/file.png')`
where we append this path to `snapshotDir` and end up in some random
place.
Also added a note to documentation.
- Source now lives at `src/test`.
- Former folio tests live at `tests/playwright-test`.
- We use `src/test/internal.ts` that exposes base test without
Playwright fixtures for most tests (to avoid modifications for now).
- Test types live in `types/testFoo.d.ts`.
- Stable test runner is installed to `tests/config/test-runner` during `npm install`.
- All deps including test-only are now listed in `package.json`.
Non-test deps must also be listed in `build_package.js` to get included.
