FAR 25, JAR 25 & CS25 (FAA, JAA & EASA requirements) give the specifications that large aircraft have to meet to achieve certification. They do not tell you how to achieve them, although some have Acceptable Means of Compliance (AMC) which specify certain tests. 25.853 and Appendix F is one, with regard to flamability, smoke and toxicity for cabin materials.
It is up to the manufacturer to satisfy the authorities that the testing etc. they have carried out demonstrates compliance with the individual requirement. There are 10 Means of Compliance (MC)
MC0 Compliance statement - type design docs, methods and factors etc
MC1 Design review
MC2 Calculation/analysis
MC3 Safey assesment
MC4 Lab tests
MC5 Ground tests on related products
MC6 Flight tests
MC7 Design inspection
MC8 Flight test
MC9 Equipment qualification
It is a very long and expensive process, which is why manufacturers use several aircraft during certification to speed the process up.
I've never heard of a drop test, unless it is for landing gear testing, where the manufacturer of the gear slams the it into the ground for days on end to simulate landing loads. Flight testing does have what is called 'pilot abuse' cases including deliberate over rotation on take off and high 'flare' landings etc. We broke the 146 prototype several times doing this.
Hope this helps
DC