Simulating a Read/Write operation by FPGA in EEPROM
You can find simulation models for various EEPROM from the sites such as:

Free Memory Foundry or other similar sites. 
There you can find (for example) : "s25fl116k.vhd VHDL model of a 16-Mbit Flash Memory with 108-MHz SPI Multi I/O Bus."  I am not sure if this is something you can use or not. But if you do a quick search on Google for your specific flash memory you will find it or something similar to it to use with your test code.