To generate the example testbench, following the steps below:
1) Generate the AXI BFM core in a configuration you are interested in.
2) Right-click on the core .xci file in the Sources/Hierarchy tab and choose Open IP Example Design.
This will generate a new Vivado project with the testbench example already created and ready to simulate. See the example testbench stimulus provided for a simulation source in the new project.