I am not going to explore ton of different tools, at some point I found EDA playground website and it worked quite well for me. So this is a deal, we will use that for online quick tests. Note: you will need to use a working email for a free account.

I prefer to use xcelium simulator since it align with xrun command we use in cadence. They start the sim screen from two code windows: left one for the testbench and the right one for the block itself, though I did not get why do we need it, you can as well add new tab as new file or describe a new module right inside of the testbench code.