Include test deps in dev container

Author: ethho

.devcontainer/devcontainer.json

@@ -28,7 +28,7 @@
 	// "runServices": [],
 	// Uncomment the next line if you want to keep your containers running after VS Code shuts down.
 	"shutdownAction": "stopCompose",
-	"onCreateCommand": "python3 -m pip install -e .",
+	"onCreateCommand": "python3 -m pip install -e .[test]",
 	"features": {
 		"ghcr.io/devcontainers/features/git:1": {},
 		"ghcr.io/devcontainers/features/docker-in-docker:2": {},