unit tests for remix-tests CLI usage

libs/remix-tests/tests/testRunner.cli.spec.ts

+import { spawnSync, execSync } from 'child_process'
+import { resolve } from 'path'
+
+describe('testRunner: remix-tests CLI', () => {
+    // remix-tests binary, after build, is used as executable 
+    const executablePath = resolve(__dirname + '/../../../dist/libs/remix-tests/bin/remix-tests')
+    const result = spawnSync('ls', { cwd: resolve(__dirname + '/../../../dist/libs/remix-tests') })
+    if(result) {
+        const dirContent = result.stdout.toString()
+        // Install dependencies if 'node_modules' is not already present
+        if(!dirContent.includes('node_modules')) execSync('npm install', { cwd: resolve(__dirname + '/../../../dist/libs/remix-tests') })
+    }
+
+    describe('test various CLI options', () => {
+      test('remix-tests version', () => {
+        const res = spawnSync(executablePath, ['-V'])
+        expect(res.stdout.toString().trim()).toBe(require('../package.json').version)
+      })
+    })
+})
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