[zero][system] Create jest transformer to test

zero-runtime styled components

packages/zero-jest/README.md

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+# @mui/zero-jest
+
+Jest transformer for zero-runtime styled testing support.

packages/zero-jest/package.json

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+{
+  "name": "@mui/zero-jest",
+  "version": "0.0.1-alpha.1",
+  "private": true,
+  "author": "MUI Team",
+  "description": "Jest transformer for zero-runtime styled testing support.",
+  "main": "./src/index.ts",
+  "keywords": [
+    "zero runtime",
+    "css-in-js",
+    "mui",
+    "jest"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/mui/material-ui.git",
+    "directory": "packages/zero-jest"
+  },
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/mui/material-ui/issues"
+  },
+  "homepage": "@TODO",
+  "funding": {
+    "type": "opencollective",
+    "url": "https://opencollective.com/mui"
+  },
+  "scripts": {
+    "build": "yarn build:legacy && yarn build:modern && yarn build:node && yarn build:stable && yarn build:copy-files",
+    "build:legacy": "node ../../scripts/build.mjs legacy",
+    "build:modern": "node ../../scripts/build.mjs modern",
+    "build:node": "node ../../scripts/build.mjs node",
+    "build:stable": "node ../../scripts/build.mjs stable",
+    "build:copy-files": "node ../../scripts/copyFiles.mjs",
+    "prebuild": "rimraf build tsconfig.build.tsbuildinfo",
+    "release": "yarn build && npm publish build",
+    "test": "cd ../../ && cross-env NODE_ENV=test mocha 'packages/zero-babel-plugin/**/*.test.{js,ts,tsx}'"
+  },
+  "dependencies": {
+    "@linaria/babel-preset": "^4.5.4",
+    "@linaria/utils": "^4.5.3",
+    "@mui/zero-tag-processor": "0.0.1-alpha.1",
+    "babel-jest": "^29.7.0"
+  },
+  "devDependencies": {
+    "@jest/transform": "^29.7.0"
+  },
+  "peerDependencies": {},
+  "sideEffects": false,
+  "publishConfig": {
+    "access": "public"
+  },
+  "engines": {
+    "node": ">=12.0.0"
+  }
+}

packages/zero-jest/src/index.js

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+import { TransformCacheCollection, transform as linariaTransform } from '@linaria/babel-preset';
+import { syncResolve, asyncResolveFallback } from '@linaria/utils';
+import babelJest from 'babel-jest';
+
+const transformCache = new TransformCacheCollection();
+
+function getLinariaConfig(filename, options) {
+  const { theme = {}, cssVariablesPrefix = 'mui' } = options ?? {};
+  return {
+    filename,
+    pluginOptions: {
+      themeArgs: {
+        theme,
+      },
+      cssVariablesPrefix,
+    },
+  };
+}
+
+/**
+ * @typedef {Object} TransformerConfig
+ * @property {unknown} theme
+ */
+
+/**
+ *
+ * @param {TransformerConfig} userOptions
+ * @returns
+ */
+function createZeroTransformer(userOptions) {
+  const { theme, cssVariablesPrefix = 'mui', ...rest } = userOptions;
+  const babelTransformer = babelJest.createTransformer({
+    ...rest,
+    plugins: (userOptions?.rest ?? []).concat('@mui/zero-tag-processor/pre-linaria-plugin'),
+  });
+  // eslint-disable-next-line global-require
+  const { transformSync: linariaTransformSync } = require('@linaria/babel-preset/lib/transform');
+
+  /** @type {import("@jest/transform").Transformer<TransformerConfig>} */
+  const zeroTransformer = {
+    ...babelTransformer,
+    process(sourceText, sourcePath, options) {
+      const { code } = babelTransformer.process(sourceText, sourcePath, options);
+      const linariaResult = linariaTransformSync(
+        code ?? sourceText,
+        getLinariaConfig(sourcePath, {
+          theme,
+          cssVariablesPrefix,
+        }),
+        syncResolve,
+        {},
+        transformCache,
+      );
+      return {
+        code: linariaResult?.code ?? sourceText,
+        map: linariaResult?.map,
+      };
+    },
+    async processAsync(sourceText, sourcePath, options) {
+      const { code } = babelTransformer.processAsync(sourceText, sourcePath, options);
+      const linariaResult = await linariaTransform(
+        code ?? sourceText,
+        getLinariaConfig(sourcePath, {
+          theme,
+          cssVariablesPrefix,
+        }),
+        asyncResolveFallback,
+        {},
+        transformCache,
+      );
+      return {
+        code: linariaResult?.code ?? code ?? sourceText,
+        map: linariaResult?.map,
+      };
+    },
+  };
+
+  return zeroTransformer;
+}
+
+const transformerFactory = { createTransformer: createZeroTransformer };
+
+export default transformerFactory;