fixed test issues and watch mode for unit tests

scripts/set-mock-env.ts

@@ -0,0 +1,11 @@
+import { copyFile } from 'fs';
+
+// Configure Angular `environment.ts` file path
+const sourcePath = './src/environments/mock-environment.ts';
+const targetPath = './src/environments/environment.ts';
+
+// destination.txt will be created or overwritten by default.
+copyFile(sourcePath, targetPath, (err) => {
+  if (err) throw err;
+  console.log(sourcePath + ' was copied to ' + targetPath);
+});