There were plenty of different rounds before the final interview with HR like,
1) Aptitude Test (normal RS Agarwal stuff)
2) MS Excel test (bounded time duration, so little difficult, around 5-8 questions)
3) Skills test+background check
4) Group interview (mostly the team you join, it's Line Manager, his Senior or sometimes the client too)
5) final round with HR (final person to talk to about all you queries, expectations, compensation etc.)
Most of the time employee referrals work to a great extent at TESCO-HSC.