add process test

__tests__/process.ts

@@ -0,0 +1,20 @@
+import os from 'os'
+
+// this unit is used to increase the test coverage
+describe('Process Testing', () => {
+  it('should terminate the worker pool using nodejs 12.5+', async () => {
+    Object.defineProperty(process, 'version', { value: 'v12.5.0' })
+    const { start, stop } = require('../src/job')
+    await start()
+
+    await stop()
+  })
+
+  it('should warn about the number of CPUs using more than 10 CPUs', async () => {
+    Object.defineProperty(os, 'cpus', { value: () => Array.from({ length: 12 }) })
+    const { start, stop } = require('../src/job')
+    await start()
+
+    await stop()
+  })
+})