update cpu count collector | remove npm cache from tests

Author: mvogttech

.github/workflows/test.yml

@@ -21,7 +21,6 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}
-          cache: npm
 
       - name: Install dependencies
         run: npm install

README.md

@@ -854,10 +854,12 @@ Main agent singleton instance.
 
 ## Changelog
 
-### v1.0.17 (Bug Fixes)
+### v1.0.17 (Bug Fixes & Testing)
 
 - **DDP queue unblock recursion fix** - Restructured `DDPQueueCollector.wrapUnblock()` to eliminate a remaining infinite recursion path. The catch block previously retried calling `originalUnblock()` after a failure, but `originalUnblock` can itself be a wrapper from another layer (e.g., `MethodTracer`). If that wrapper threw, the retry would re-enter it, creating unbounded mutual recursion and `RangeError: Maximum call stack size exceeded`. The fix sets the `unblocked` guard immediately on entry, isolates metrics collection in its own try/catch so failures are non-fatal, and calls `originalUnblock()` exactly once with no retry. (fixes [#7](https://github.com/SkySignalAPM/agent/issues/7))
 - **Console error object serialization** - `ErrorTracker` now properly serializes object arguments passed to `console.error()` using `JSON.stringify` instead of `String()`. Previously, `console.error('test', {a:1, b:2})` would be captured as `"test [object Object]"` — it now correctly captures `"test {"a":1,"b":2}"`. The same fix applies to `UnhandledRejection` events where the rejection reason is a plain object rather than an Error instance. Serialization is depth-limited (5 levels) and size-capped (5KB) to prevent oversized payloads from deeply nested objects. Circular references are detected and replaced with `"[Circular]"`. (fixes [#10](https://github.com/SkySignalAPM/agent/issues/10))
+- **Use `os.availableParallelism()` for CPU count** - Replaced `os.cpus().length` with `os.availableParallelism()` in `SystemMetricsCollector` and `EnvironmentCollector`. The Node.js docs advise against using `os.cpus().length` to determine available parallelism, as it can return an empty array on some systems. `os.availableParallelism()` (Node 18.14+) is the recommended API for this purpose.
+- **963 unit tests with GitHub Actions CI** - Added a comprehensive standalone test suite (Mocha + Chai + Sinon) covering all collectors, client modules, and library utilities. Includes regression tests for bugs #7 and #10. Tests run via `npm test` without requiring a Meteor environment. Added GitHub Actions workflow (`.github/workflows/test.yml`) to run tests on push/PR against Node.js 20 and 22.
 
 ### v1.0.16 (Bug Fixes)
 

lib/collectors/EnvironmentCollector.js

@@ -145,7 +145,7 @@ export default class EnvironmentCollector {
       platform: os.platform(),
       release: os.release(),
       arch: os.arch(),
-      cpuCount: os.cpus().length,
+      cpuCount: os.availableParallelism(),
       cpuModel: os.cpus()[0]?.model || "unknown",
       totalMemory: os.totalmem(),
       freeMemory: os.freemem(),

lib/collectors/SystemMetricsCollector.js

@@ -133,7 +133,7 @@ export default class SystemMetricsCollector {
 
       // CPU metrics
       const cpuUsage = this._getCpuUsage();
-      const cpuCores = os.cpus().length;
+      const cpuCores = os.availableParallelism();
       const loadAverage = os.loadavg();
 
       // Memory metrics