diff --git a/README.md b/README.md
index bcb8a735..d9fb287f 100644
--- a/README.md
+++ b/README.md
@@ -53,6 +53,8 @@ Issue the following to run the tests:
 python -m pytest test/
 ```
 
+Some tests will fail if Open AI `gym` is not installed on your machine.
+
 ## Background
 
 The simulation of biologically plausible spiking neuron dynamics can be challenging. It is typically done by solving ordinary differential equations (ODEs) which describe said dynamics. PyTorch does not explicitly support the solution of differential equations (as opposed to [`brian2`](https://github.com/brian-team/brian2), for example), but we can convert the ODEs defining the dynamics into difference equations and solve them at regular, short intervals (a `dt` on the order of 1 millisecond) as an approximation. Of course, under the hood, packages like `brian2` are doing the same thing. Doing this in [`PyTorch`](http://pytorch.org/) is exciting for a few reasons: