enable saving config between steps in a single feature

pkg/environment/magic.go

@@ -134,6 +134,11 @@ func (mr *MagicEnvironment) Prerequisite(ctx context.Context, t *testing.T, f *f
 	})
 }
 
+// Test implements Environment.Test.
+// In the MagicEnvironment implementation, the Store that is inside of the
+// Feature will be assigned to the context. If no Store is set on Feature,
+// Test will create a new store.KVStore and set it on the feature and then
+// apply it to the Context.
 func (mr *MagicEnvironment) Test(ctx context.Context, t *testing.T, f *feature.Feature) {
 	t.Helper() // Helper marks the calling function as a test helper function.
 

pkg/state/context.go

@@ -23,10 +23,15 @@ import (
 
 type envKey struct{}
 
+// ContextWith decorates the given context with the provided Store, and returns
+// the resulting context.
 func ContextWith(ctx context.Context, s Store) context.Context {
 	return context.WithValue(ctx, envKey{}, s)
 }
 
+// FromContext returns the Store from Context, if not found FromContext will
+// panic.
+// TODO: revisit if we really want to panic here... likely not.
 func FromContext(ctx context.Context) Store {
 	if e, ok := ctx.Value(envKey{}).(Store); ok {
 		return e