test: retry flaky pack/install test (#1316)

Retry the pack and install test, which has several moving parts and
fails once in a blue moon. Refactored such that tests are now independent,
i.e., npm pack and webpack can be run independently.

Fixes #1315

system-test/test.kitchen.ts

@@ -13,7 +13,7 @@
 // limitations under the License.
 
 import * as assert from 'assert';
-import {describe, it, before, after} from 'mocha';
+import {describe, it, afterEach} from 'mocha';
 import * as execa from 'execa';
 import * as fs from 'fs';
 import * as mv from 'mv';
@@ -25,40 +25,51 @@ import {promisify} from 'util';
 const mvp = promisify(mv) as {} as (...args: string[]) => Promise<void>;
 const ncpp = promisify(ncp);
 const keep = !!process.env.GALN_KEEP_TEMPDIRS;
-const stagingDir = tmp.dirSync({keep, unsafeCleanup: true});
-const stagingPath = stagingDir.name;
 // eslint-disable-next-line @typescript-eslint/no-var-requires
 const pkg = require('../../package.json');
 
+let stagingDir: tmp.DirResult;
+let stagingPath: string;
+async function packAndInstall() {
+  stagingDir = tmp.dirSync({keep, unsafeCleanup: true});
+  stagingPath = stagingDir.name;
+  await execa('npm', ['pack'], {stdio: 'inherit'});
+  const tarball = `${pkg.name}-${pkg.version}.tgz`;
+  // stagingPath can be on another filesystem so fs.rename() will fail
+  // with EXDEV, hence we use `mv` module here.
+  await mvp(tarball, `${stagingPath}/google-auth-library.tgz`);
+  await ncpp('system-test/fixtures/kitchen', `${stagingPath}/`);
+  await execa('npm', ['install'], {cwd: `${stagingPath}/`, stdio: 'inherit'});
+}
+
 describe('pack and install', () => {
   /**
    * Create a staging directory with temp fixtures used to test on a fresh
    * application.
    */
-  before('should be able to use the d.ts', async function () {
+  it('should be able to use the d.ts', async function () {
+    // npm, once in a blue moon, fails during pack process. If this happens,
+    // we should be safe to retry.
+    //this.retries(3);
     this.timeout(40000);
-    console.log(`${__filename} staging area: ${stagingPath}`);
-    await execa('npm', ['pack'], {stdio: 'inherit'});
-    const tarball = `${pkg.name}-${pkg.version}.tgz`;
-    // stagingPath can be on another filesystem so fs.rename() will fail
-    // with EXDEV, hence we use `mv` module here.
-    await mvp(tarball, `${stagingPath}/google-auth-library.tgz`);
-    await ncpp('system-test/fixtures/kitchen', `${stagingPath}/`);
-    await execa('npm', ['install'], {cwd: `${stagingPath}/`, stdio: 'inherit'});
+    await packAndInstall();
   });
 
-  it('should be able to webpack the library', async () => {
+  it('should be able to webpack the library', async function () {
+    this.retries(3);
+    this.timeout(40000);
+    await packAndInstall();
     // we expect npm install is executed in the before hook
     await execa('npx', ['webpack'], {cwd: `${stagingPath}/`, stdio: 'inherit'});
     const bundle = path.join(stagingPath, 'dist', 'bundle.min.js');
     const stat = fs.statSync(bundle);
     assert(stat.size < 256 * 1024);
-  }).timeout(20000);
+  });
 
   /**
    * CLEAN UP - remove the staging directory when done.
    */
-  after('cleanup staging', () => {
+  afterEach('cleanup staging', () => {
     if (!keep) {
       stagingDir.removeCallback();
     }