build(test): recursively find test files; fail on unsupported dependency versions (#728)

This PR was generated using Autosynth. 🌈

Synth log will be available here:
https://source.cloud.google.com/results/invocations/28f926df-4479-489a-b60f-ecf7782e1eb7/targets

- [ ] To automatically regenerate this PR, check this box.

Source-Link: googleapis/synthtool@fdd03c1

Author: yoshi-automation

.github/workflows/ci.yaml

@@ -16,7 +16,7 @@ jobs:
         with:
           node-version: ${{ matrix.node }}
       - run: node --version
-      - run: npm install
+      - run: npm install --engine-strict
       - run: npm test
       - name: coverage
         uses: codecov/codecov-action@v1

.mocharc.js

@@ -14,7 +14,8 @@
 const config = {
   "enable-source-maps": true,
   "throw-deprecation": true,
-  "timeout": 10000
+  "timeout": 10000,
+  "recursive": true
 }
 if (process.env.MOCHA_THROW_DEPRECATION === 'false') {
   delete config['throw-deprecation'];

synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/nodejs-datastore.git",
-        "sha": "aedbe261308def60e6444022ba72f1caaab02b35"
+        "sha": "fa5faacb16b8c021314348acc5534e1802e0826e"
       }
     },
     {
@@ -19,7 +19,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "8cf6d2834ad14318e64429c3b94f6443ae83daf9"
+        "sha": "fdd03c161003ab97657cc0218f25c82c89ddf4b6"
       }
     }
   ],