docs: add test enclave usage example

README.md

@@ -1,12 +1,36 @@
 # nixsgx
 
-This repository contains a Nix flake with up2date packages for the Intel SGX SDK and gramine.
+This repository contains a Nix flake with up-to-date packages for the Intel SGX SDK and gramine.
 
 Hopefully most of the packages will be upstreamed to nixpkgs at some point.
 
 All package builds should be reproducible and therefore can be used to build reproducible enclave images.
 
 ## Usage
 
-See: https://github.com/matter-labs/teepot
-and https://github.com/matter-labs/era-fee-withdrawer/tree/gramine-sgx
+### Test enclave
+
+A testing enclave container is provided and can be ran like so:
+
+```sh
+# Build the dcap (or azure) container variant
+nix build .#nixsgx-test-sgx-dcap
+
+# Load image into docker
+docker load < result
+
+# Run the enclave, binding the sgx devices
+docker run -i --init --rm \
+  --device /dev/sgx_enclave \
+  --device /dev/sgx_provision \
+  nixsgx-test-sgx-dcap:latest
+```
+
+> Note: An external aesmd instance can be provided by mounting the socket to the container: `-v /var/run/aesmd/aesm.socket:/var/run/aesmd/aesm.socket`
+
+### Reference projects
+
+The following projects provide reproducible enclaves using nixsgx:
+
+- https://github.com/matter-labs/teepot
+- https://github.com/matter-labs/era-fee-withdrawer/tree/gramine-sgx