Use vm.Script and refactor coverage caching. (#1239)

* Use `vm.Script`.

* Rewrite basic coverage support in Jest.

* Move `vm.Script` creation and caching into `transform`.

* Copy all jest packages into example folders.

This ensures we are using the latest version of every package.

* Cache the wrapped code.

* Use babel-jest for Jest itself; update setup.

* Added a transform.js test.
* Relax jest.mock babel transform restrictions.
* Updated package.json and .npmignore for all packages.

* Make watch script resilient to deleted files.

Author: cpojer

.babelrc

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    "syntax-trailing-function-commas",
+    "transform-flow-strip-types"
+  ],
+  "retainLines": true
+}

examples/react/package.json

@@ -1,7 +1,7 @@
 {
   "dependencies": {
-    "react": "~0.14.0",
-    "react-dom": "~0.14.0"
+    "react": "~15.2.0",
+    "react-dom": "~15.2.0"
   },
   "devDependencies": {
     "babel-jest": "*",

integration_tests/__tests__/snapshot-test.js

@@ -26,7 +26,7 @@ const originalTestPath = path.resolve(
   __dirname,
   '../snapshot/__tests__/snapshot-test.js'
 );
-const originalTestContent = fs.readFileSync(originalTestPath, 'utf-8');
+const originalTestContent = fs.readFileSync(originalTestPath, 'utf8');
 const copyOfTestPath = originalTestPath.replace('.js', '_copy.js');
 
 const snapshotEscapeDir =
@@ -49,7 +49,7 @@ const fileExists = filePath => {
 const getSnapshotOfCopy = () => {
   const exports = Object.create(null);
   // eslint-disable-next-line no-eval
-  eval(fs.readFileSync(snapshotOfCopy, 'utf-8'));
+  eval(fs.readFileSync(snapshotOfCopy, 'utf8'));
   return exports;
 };
 

package.json

@@ -24,6 +24,7 @@
     "clean": "rm -rf ./packages/*/node_modules; npm run build-clean",
     "lint": "eslint .",
     "postinstall": "node ./scripts/postinstall.js && node ./scripts/build.js",
+    "publish": "npm run build-clean && npm run build && lerna publish",
     "t": "node ./scripts/test.js",
     "test": "npm run typecheck && npm run lint && npm run build && npm run t",
     "typecheck": "flow check",

packages/babel-jest/.npmignore

@@ -0,0 +1,3 @@
+**/__mocks__/**
+**/__tests__/**
+src

packages/babel-plugin-jest-hoist/.babelrc

@@ -1,3 +1,3 @@
 {
-  "presets": ["es2015", {plugins: ["./"]}]
+  "presets": ["es2015", {"plugins": ["./"]}]
 }

packages/babel-plugin-jest-hoist/.npmignore

@@ -1,2 +1,3 @@
-__tests__/
-__test_modules__/
+**/__mocks__/**
+**/__tests__/**
+src

packages/babel-plugin-jest-hoist/package.json

@@ -12,7 +12,7 @@
     "react": "^0.14.0"
   },
   "jest": {
-    "rootDir": "./build",
+    "rootDir": "./src",
     "scriptPreprocessor": "../../babel-jest",
     "testEnvironment": "node"
   },

packages/babel-plugin-jest-hoist/src/index.js

@@ -14,10 +14,12 @@ function invariant(condition, message) {
   }
 }
 
-// We allow `jest`, `require`, all default Node.js globals and all ES2015
-// built-ins to be used inside of a `jest.mock` factory.
+// We allow `jest`, `expect`, `require`, all default Node.js globals and all
+// ES2015 built-ins to be used inside of a `jest.mock` factory.
+// We also allow variables prefixed with `mock` as an escape-hatch.
 const WHITELISTED_IDENTIFIERS = {
   jest: true,
+  expect: true,
   require: true,
   Infinity: true,
   NaN: true,
@@ -103,12 +105,16 @@ FUNCTIONS.mock = args => {
 
       if (!found) {
         invariant(
-          scope.hasGlobal(name) && WHITELISTED_IDENTIFIERS[name],
-          'The second argument of `jest.mock()` is not allowed to ' +
-          'reference any outside variables.\n' +
+          (scope.hasGlobal(name) && WHITELISTED_IDENTIFIERS[name]) ||
+          /^mock/.test(name),
+          'The module factory of `jest.mock()` is not allowed to ' +
+          'reference any out-of-scope variables.\n' +
           'Invalid variable access: ' + name + '\n' +
           'Whitelisted objects: ' +
-          Object.keys(WHITELISTED_IDENTIFIERS).join(', ') + '.',
+          Object.keys(WHITELISTED_IDENTIFIERS).join(', ') + '.\n' +
+          'Note: This is a precaution to guard against uninitialized mock ' +
+          'variables. If it is ensured that the mock is required lazily, ' +
+          'variable names prefixed with `mock` are permitted.',
         );
       }
     }

packages/babel-preset-jest/.npmignore

@@ -0,0 +1,3 @@
+**/__mocks__/**
+**/__tests__/**
+src