Fix: npm prepare script on Windows (refs #166) (#168)

* Chore: Test on Windows and macOS

* Fix: npm prepare script on Windows (refs #166)

The previous script worked on macOS and Linux, but I neglected to
consider Windows. This wouldn't affect users thankfully, only
developers, so the blast radius would have been small had it not been
caught. Now that we're testing on Windows, future bugs like this should
be caught. I'm out of ideas for doing this entirely inside npm scripts,
so I broke down and did it in JS.

* Chore: Increase test timeout for Windows and macOS runners

They occasionally exhibit extremely slow filesystem performance.

* Add npm-prepare script JSDoc header

.github/workflows/ci.yml

@@ -24,10 +24,16 @@ jobs:
 
   test:
     name: Test
-    runs-on: ubuntu-latest
     strategy:
       matrix:
+        os: [ubuntu-latest]
         node-version: ["8.10.0", 8.x, 10.x, 12.x, 13.x, 14.x]
+        include:
+        - os: windows-latest
+          node: "12.x"
+        - os: macOS-latest
+          node: "12.x"
+    runs-on: ${{ matrix.os }}
     steps:
     - name: Checkout
       uses: actions/checkout@v1

npm-prepare.js

@@ -0,0 +1,20 @@
+/**
+ * @fileoverview Install examples' dependencies as part of local npm install for
+ * development and CI.
+ * @author btmills
+ */
+
+"use strict";
+
+const childProcess = require("child_process");
+const fs = require("fs");
+const path = require("path");
+
+const examplesDir = path.resolve(__dirname, "examples");
+const examples = fs.readdirSync(examplesDir);
+
+for (const example of examples) {
+    childProcess.execSync("npm install", {
+        cwd: path.resolve(examplesDir, example)
+    });
+}

package.json

@@ -21,7 +21,7 @@
   ],
   "scripts": {
     "lint": "eslint --ext js,md .",
-    "prepare": "for example in examples/*; do (cd \"$example\" && npm install); done",
+    "prepare": "node ./npm-prepare.js",
     "test": "npm run lint && npm run test-cov",
     "test-cov": "nyc _mocha -- -c tests/{examples,lib}/**/*.js",
     "generate-release": "eslint-generate-release",

tests/lib/plugin.js

@@ -55,7 +55,7 @@ describe("recommended config", () => {
                 // hook-level timeouts uses `this`, so disable the rule.
                 // https://mochajs.org/#hook-level
                 // eslint-disable-next-line no-invalid-this
-                this.timeout(9999);
+                this.timeout(30000);
 
                 execSync("npm link && npm link eslint-plugin-markdown");
             } else {