There was no interview, HR contacted via personal WhatsApp. Quick process. I do assume whether or not an interview is required is based on the position you apply for and your locale, so do take this with a mega grain of salt.
It was basically another test, they didn't ask questions about me. I basically took another test during the interview with the interviewer watching me. It was unexpected although nothing to difficult
Interview questions [1]
Question 1
What is a polynomial, L'hopitals rule, trig identities
