feat(examples): add Jest example

This PR adds an example of how you might create a Jest rule

Unfortunately Jest does not handle symlinks very well so we have to add some patches so that it behaves correctly(See: jasongwartz/bazel_rules_nodejs_contrib#4 (comment))

examples/jest/.bazelignore

@@ -0,0 +1 @@
+node_modules

examples/jest/.bazelrc

@@ -0,0 +1 @@
+import %workspace%/../../common.bazelrc

examples/jest/BUILD.bazel

@@ -0,0 +1,24 @@
+load(":jest.bzl", "jest_test")
+
+jest_test(
+    name = "test",
+    srcs = [
+        "index.test.js",
+        "index2.test.js",
+    ],
+    jest_config = ":jest.config.js",
+    deps = [
+        ":extra.js",
+        ":index.js",
+        "@npm//@babel/core",
+        "@npm//@babel/preset-env",
+        "@npm//@jest/transform",
+        "@npm//babel-jest",
+    ],
+)
+
+# Just a dummy test so that we have a test target for //... on certain bazelci platforms with bazel_integration_test
+sh_test(
+    name = "dummy_test",
+    srcs = ["dummy_test.sh"],
+)

examples/jest/README.md

@@ -0,0 +1,3 @@
+# Jest example
+
+This example shows how you might use the Jest testing framework

examples/jest/WORKSPACE

@@ -0,0 +1,48 @@
+# Copyright 2019 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+workspace(
+    name = "examples_jest",
+    managed_directories = {"@npm": ["node_modules"]},
+)
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "build_bazel_rules_nodejs",
+    sha256 = "ad4be2c6f40f5af70c7edf294955f9d9a0222c8e2756109731b25f79ea2ccea0",
+    urls = ["https://github.com/bazelbuild/rules_nodejs/releases/download/0.38.3/rules_nodejs-0.38.3.tar.gz"],
+)
+
+load("@build_bazel_rules_nodejs//:index.bzl", "yarn_install")
+
+yarn_install(
+    name = "npm",
+    data = [
+        "//:tools/patches/@jest+core+24.7.1.patch",
+        "//:tools/patches/@jest+transform+24.7.1.patch",
+        "//:tools/patches/jest-cli+24.7.1.patch",
+        "//:tools/patches/jest-config+24.7.1.patch",
+        "//:tools/patches/jest-haste-map+24.7.1.patch",
+        "//:tools/patches/jest-resolve+24.7.1.patch",
+        "//:tools/patches/jest-runtime+24.7.1.patch",
+    ],
+    package_json = "//:package.json",
+    quiet = False,
+    yarn_lock = "//:yarn.lock",
+)
+
+load("@npm//:install_bazel_dependencies.bzl", "install_bazel_dependencies")
+
+install_bazel_dependencies()

examples/jest/babel.config.js

@@ -0,0 +1,12 @@
+module.exports = {
+  presets: [
+    [
+      '@babel/preset-env',
+      {
+        targets: {
+          node: 'current',
+        },
+      },
+    ],
+  ],
+};

examples/jest/dummy_test.sh

@@ -0,0 +1,2 @@
+echo "Just a dummy test so that we have a test target for //... on certain bazelci platforms with bazel_integration_test"
+exit 0

examples/jest/extra.js

@@ -0,0 +1 @@
+export default 'test';

examples/jest/index.js

@@ -0,0 +1,3 @@
+import extra from './extra';
+
+export default extra;

examples/jest/index.test.js

@@ -0,0 +1,5 @@
+import indexfile from './index.js';
+
+test('it should work', () => {
+  expect(indexfile).toBe('test');
+});

examples/jest/index2.test.js

@@ -0,0 +1,5 @@
+import indexfile from './index.js';
+
+test('it should work', () => {
+  expect(indexfile).toBe('test');
+});

examples/jest/jest.bzl

@@ -0,0 +1,25 @@
+"Shows how you might create a macro for the autogeneratd Jest rule"
+
+load("@npm//jest-cli:index.bzl", _jest_test = "jest_test")
+
+def jest_test(name, srcs, deps, jest_config):
+    "A macro around the autogenerated jest_test rule"
+    jest_config_location_arg = "$(location " + jest_config + ")"
+    jest_test_path_arg = ["--runTestsByPath"]
+    for src in srcs:
+        jest_test_path_arg = jest_test_path_arg + ["$(location " + src + ")"]
+
+    args = [
+        "--config",
+        jest_config_location_arg,
+        "--no-cache",
+        "--no-watchman",
+        "--ci",
+        "--runTestsByPath",
+    ] + jest_test_path_arg
+
+    _jest_test(
+        name = name,
+        data = [jest_config] + srcs + deps,
+        args = args,
+    )

examples/jest/jest.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  testEnvironment: 'node',
+
+  transform: {'^.+\\.jsx?$': 'babel-jest'},
+  testMatch: ['**/*.test.js']
+};

examples/jest/package.json

@@ -0,0 +1,21 @@
+{
+    "name": "jest_example",
+    "private": true,
+    "devDependencies": {
+        "@babel/cli": "^7.6.0",
+        "@babel/core": "^7.6.0",
+        "@babel/preset-env": "^7.6.0",
+        "@jest/transform": "24.7.1",
+        "babel-jest": "24.7.1",
+        "jest-cli": "24.7.1",
+        "jest-config": "24.7.1",
+        "jest-haste-map": "24.7.1",
+        "jest-resolve": "24.7.1",
+        "jest-runtime": "24.7.1",
+        "patch-package": "6.1.2"
+    },
+    "scripts": {
+        "test": "bazel test ...",
+        "postinstall": "patch-package --patch-dir=./tools/patches"
+    }
+}

examples/jest/tools/patches/@jest+core+24.7.1.patch

@@ -0,0 +1,13 @@
+diff --git a/node_modules/@jest/core/build/runJest.js b/node_modules/@jest/core/build/runJest.js
+index 5afb90a..9a2c15b 100644
+--- a/node_modules/@jest/core/build/runJest.js
++++ b/node_modules/@jest/core/build/runJest.js
+@@ -244,7 +244,7 @@ const processResults = (runResults, options) => {
+
+   if (isJSON) {
+     if (outputFile) {
+-      const cwd = (0, _realpathNative().sync)(process.cwd());
++      const cwd = process.cwd();
+
+       const filePath = _path().default.resolve(cwd, outputFile);
+

examples/jest/tools/patches/@jest+transform+24.7.1.patch

@@ -0,0 +1,13 @@
+diff --git a/node_modules/@jest/transform/build/ScriptTransformer.js b/node_modules/@jest/transform/build/ScriptTransformer.js
+index 81397c7..7589de2 100644
+--- a/node_modules/@jest/transform/build/ScriptTransformer.js
++++ b/node_modules/@jest/transform/build/ScriptTransformer.js
+@@ -328,7 +328,7 @@ class ScriptTransformer {
+   }
+
+   transformSource(filepath, content, instrument) {
+-    const filename = this._getRealPath(filepath);
++    const filename = filepath;
+
+     const transform = this._getTransformer(filename);
+

examples/jest/tools/patches/jest-cli+24.7.1.patch

@@ -0,0 +1,26 @@
+diff --git a/node_modules/jest-cli/build/cli/index.js b/node_modules/jest-cli/build/cli/index.js
+index 831a476..46f7570 100644
+--- a/node_modules/jest-cli/build/cli/index.js
++++ b/node_modules/jest-cli/build/cli/index.js
+@@ -271,7 +271,7 @@ const getProjectListFromCLIArgs = (argv, project) => {
+
+   if (!projects.length && process.platform === 'win32') {
+     try {
+-      projects.push((0, _realpathNative().sync)(process.cwd()));
++      projects.push(process.cwd());
+     } catch (err) {
+       // do nothing, just catch error
+       // process.binding('fs').realpath can throw, e.g. on mapped drives
+diff --git a/node_modules/jest-cli/build/init/index.js b/node_modules/jest-cli/build/init/index.js
+index cae2fc2..7f38281 100644
+--- a/node_modules/jest-cli/build/init/index.js
++++ b/node_modules/jest-cli/build/init/index.js
+@@ -134,7 +134,7 @@ var _default =
+   /*#__PURE__*/
+   (function() {
+     var _ref = _asyncToGenerator(function*(
+-      rootDir = (0, _realpathNative().sync)(process.cwd())
++      rootDir = process.cwd()
+     ) {
+       // prerequisite checks
+       const projectPackageJsonPath = _path().default.join(

examples/jest/tools/patches/jest-config+24.7.1.patch

@@ -0,0 +1,35 @@
+diff --git a/node_modules/jest-config/build/getCacheDirectory.js b/node_modules/jest-config/build/getCacheDirectory.js
+index 7e64ba6..6ea2cfd 100644
+--- a/node_modules/jest-config/build/getCacheDirectory.js
++++ b/node_modules/jest-config/build/getCacheDirectory.js
+@@ -50,7 +50,7 @@ const getCacheDirectory = () => {
+     getuid = _process.getuid;
+
+   const tmpdir = _path().default.join(
+-    (0, _realpathNative().sync)(_os().default.tmpdir()),
++    _os().default.tmpdir(),
+     'jest'
+   );
+
+diff --git a/node_modules/jest-config/build/normalize.js b/node_modules/jest-config/build/normalize.js
+index ce37c38..c34497a 100644
+--- a/node_modules/jest-config/build/normalize.js
++++ b/node_modules/jest-config/build/normalize.js
+@@ -428,7 +428,7 @@ const normalizeRootDir = options => {
+
+   try {
+     // try to resolve windows short paths, ignoring errors (permission errors, mostly)
+-    options.rootDir = (0, _realpathNative().sync)(options.rootDir);
++    options.rootDir = options.rootDir;
+   } catch (e) {
+     // ignored
+   }
+@@ -1004,7 +1004,7 @@ function normalize(options, argv, configPath, projectIndex = Infinity) {
+
+   try {
+     // try to resolve windows short paths, ignoring errors (permission errors, mostly)
+-    newOptions.cwd = (0, _realpathNative().sync)(process.cwd());
++    newOptions.cwd = process.cwd();
+   } catch (e) {
+     // ignored
+   }

examples/jest/tools/patches/jest-haste-map+24.7.1.patch

@@ -0,0 +1,26 @@
+diff --git a/node_modules/jest-haste-map/build/crawlers/node.js b/node_modules/jest-haste-map/build/crawlers/node.js
+index a179225..06106b9 100644
+--- a/node_modules/jest-haste-map/build/crawlers/node.js
++++ b/node_modules/jest-haste-map/build/crawlers/node.js
+@@ -165,7 +165,7 @@ function find(roots, extensions, ignore, callback) {
+ }
+
+ function findNative(roots, extensions, ignore, callback) {
+-  const args = Array.from(roots);
++  const args = Array.from(['-L'].concat(roots));
+   args.push('-type', 'f');
+
+   if (extensions.length) {
+diff --git a/node_modules/jest-haste-map/build/index.js b/node_modules/jest-haste-map/build/index.js
+index eb8d84f..97ec2c1 100644
+--- a/node_modules/jest-haste-map/build/index.js
++++ b/node_modules/jest-haste-map/build/index.js
+@@ -403,7 +403,7 @@ class HasteMap extends _events().default {
+       roots: Array.from(new Set(options.roots)),
+       skipPackageJson: !!options.skipPackageJson,
+       throwOnModuleCollision: !!options.throwOnModuleCollision,
+-      useWatchman: options.useWatchman == null ? true : options.useWatchman,
++      useWatchman: false,
+       watch: !!options.watch
+     };
+     this._console = options.console || global.console;

examples/jest/tools/patches/jest-resolve+24.7.1.patch

@@ -0,0 +1,46 @@
+diff --git a/node_modules/jest-resolve/build/defaultResolver.js b/node_modules/jest-resolve/build/defaultResolver.js
+index 64e7387..b5b74d3 100644
+--- a/node_modules/jest-resolve/build/defaultResolver.js
++++ b/node_modules/jest-resolve/build/defaultResolver.js
+@@ -137,7 +137,7 @@ function resolveSync(target, options) {
+     if (result) {
+       // Dereference symlinks to ensure we don't create a separate
+       // module instance depending on how it was referenced.
+-      result = _fs().default.realpathSync(result);
++      // result = _fs().default.realpathSync(result);
+     }
+
+     return result;
+diff --git a/node_modules/jest-resolve/build/index.js b/node_modules/jest-resolve/build/index.js
+index 8e6bfe0..c3a9f27 100644
+--- a/node_modules/jest-resolve/build/index.js
++++ b/node_modules/jest-resolve/build/index.js
+@@ -57,7 +57,7 @@ function _defineProperty(obj, key, value) {
+ const NATIVE_PLATFORM = 'native'; // We might be inside a symlink.
+
+ const cwd = process.cwd();
+-const resolvedCwd = (0, _realpathNative().sync)(cwd) || cwd;
++const resolvedCwd = cwd;
+ const nodePaths = process.env.NODE_PATH
+   ? process.env.NODE_PATH.split(_path().default.delimiter)
+       .filter(Boolean) // The resolver expects absolute paths.
+diff --git a/node_modules/jest-resolve/build/nodeModulesPaths.js b/node_modules/jest-resolve/build/nodeModulesPaths.js
+index 8d9d10f..5d55456 100644
+--- a/node_modules/jest-resolve/build/nodeModulesPaths.js
++++ b/node_modules/jest-resolve/build/nodeModulesPaths.js
+@@ -55,14 +55,7 @@ function nodeModulesPaths(basedir, options) {
+   } // The node resolution algorithm (as implemented by NodeJS and TypeScript)
+   // traverses parents of the physical path, not the symlinked path
+
+-  let physicalBasedir;
+-
+-  try {
+-    physicalBasedir = (0, _realpathNative().sync)(basedirAbs);
+-  } catch (err) {
+-    // realpath can throw, e.g. on mapped drives
+-    physicalBasedir = basedirAbs;
+-  }
++  let physicalBasedir = basedirAbs;
+
+   const paths = [physicalBasedir];
+

examples/jest/tools/patches/jest-runtime+24.7.1.patch

@@ -0,0 +1,13 @@
+diff --git a/node_modules/jest-runtime/build/cli/index.js b/node_modules/jest-runtime/build/cli/index.js
+index 47f4f5d..ff2bbc1 100644
+--- a/node_modules/jest-runtime/build/cli/index.js
++++ b/node_modules/jest-runtime/build/cli/index.js
+@@ -203,7 +203,7 @@ function run(cliArgv, cliInfo) {
+     return;
+   }
+
+-  const root = (0, _realpathNative().sync)(process.cwd());
++  const root = process.cwd();
+
+   const filePath = _path().default.resolve(root, argv._[0]);
+