Add test script to run just validation tests and update readme

projects/plugins/jetpack/extensions/shared/test/block-fixtures.md

@@ -23,23 +23,23 @@ the parsing and serialization of that block. Additionally, each deprecation for
 a block should also have a fixture.
 
 These fixtures must be named like
-`core__blockname{__*,}.{html,json,serialized.html}`. For example, for the
-`core/image` block, the following four fixture files must exist:
+`jetpack__blockname{__*,}.{html,json,serialized.html}`. For example, for the
+`jetpack/whatsapp-button` block, the following four fixture files must exist:
 
-1. `core__image.html` (or `core__image__specific-test-name.html`). Must
+1. `jetpack__whatsapp-button.html` (or `jetpack__whatsapp-button__specific-test-name.html`). Must
    contain a `<!-- wp:core/image -->` block.
-2. `core__image.parsed.json` (or `core__image__specific-test-name.parsed.json`).
-3. `core__image.json` (or `core__image__specific-test-name.json`).
-4. `core__image.serialized.html` (or
-   `core__image__specific-test-name.serialized.html`).
+2. `jetpack__whatsapp-button__image.parsed.json` (or `core__image__specific-test-name.parsed.json`).
+3. `jetpack__whatsapp-button.json` (or `jetpack__whatsapp-button__specific-test-name.json`).
+4. `jetpack__whatsapp-button.serialized.html` (or
+   `jetpack__whatsapp-button.serialized.html`).
 
 For each deprecation a fixture should exist with the filename format
-`core__image__deprecated-1.html`, with the number relating to the deprecation version.
+`jetpack__whatsapp-button__deprecated-1.html`, with the number relating to the deprecation version.
 
 Ideally all important attributes and features of the block should be tested
-this way.
+this way, for example with a gallery block where adding a  `linkTo` attribute may significantly change the saved content of the block there might be a fixture that has the image tag wrapped in a `<a>` and named `jetpack__tiled-gallery__link-to-attachment.html`.
 
-## Creating Fixtures
+## Creating fixtures
 
 When adding a new fixtures, only the first file above (1, e.g. `core__image.html`) needs
 to be created manually, the other files are generated from this first file.
@@ -73,7 +73,13 @@ contents of the `.json` and `.serialized.html` files are as expected.
 In particular, check that the `isValid` property is `true`, and that
 the attributes are serialized correctly.
 
-## Updating Fixtures
+## Add a deprecation fixture
+
+When adding a fixture for a block deprecation follow the same steps as above but name the new fixture file as `core__image__dreprecated-1.html`) where the number at the end represents the deprecation version. The content of this file should match the saved block content the deprecated version of the block
+
+In the case of deprecations the content of the `.json` and `.serialized.html` files should match the content of the produced by the latest version of the block save method, ie. they should mimic what would happen to a blocks content when a deprecated version is loaded in the editor and migrated to be compatible with the new save method.
+
+## Updating fixtures
 
 The process for updating fixtures for existing tests is similar to that for creating them:
 
@@ -94,6 +100,10 @@ yarn fixtures:regenerate
 After regenerating fixtures, check the diff (using git/github) to check that the changes were expected
 and the block is still valid (`isValid` is `true`).
 
+## Running the tests
+
+The fixture tests will be run as part of running the `fixtures:generate` and `fixtures:regenerate` scripts and also as part of the `yarn test-extensions` test run. They can also be run independently with `yarn fixtures:test`
+
 ## Related
 
 See the

projects/plugins/jetpack/package.json

@@ -37,6 +37,7 @@
 		"distclean": "rm -rf node_modules && yarn clean",
 		"fixtures:regenerate": "REGENERATE_FIXTURES=y GENERATE_MISSING_FIXTURES=y yarn jest",
 		"fixtures:generate": "GENERATE_MISSING_FIXTURES=y yarn jest",
+		"fixtures:test": "jest validate.js",
 		"install-if-deps-outdated": "yarn install --check-files --production=false --frozen-lockfile",
 		"test-adminpage": "yarn test-client && yarn test-gui",
 		"test-client": "NODE_ENV=test NODE_PATH=tests:_inc/client tests/runner.js",