Test harness for HyphaeVM

This commit adds a testing framework for HyphaeVM which enables
testing various aspects of the VM state after running input programs
against a VM with possibly preinitialized state.

This includes a builder pattern initializer for the VM, and bespoke
logic for a test case tester.

Signed-off-by: Ava Affine <ava@sunnypup.io>

hyphae/src/stackstack.rs

@@ -24,16 +24,63 @@ struct StackInner<T: Sized> {
     pub data: T
 }
 
+impl<T: Clone> Clone for StackInner<T> {
+    fn clone(&self) -> Self {
+        StackInner{
+            next: self.next.clone(),
+            data: self.data.clone()
+        }
+    }
+
+    fn clone_from(&mut self, source: &Self) {
+        *self = source.clone()
+    }
+}
+
 struct Stack<T: Sized> (Rc<Option<StackInner<T>>>);
 
+impl<T: Clone> Clone for Stack<T> {
+    fn clone(&self) -> Self {
+        Stack(Rc::from((*self.0).clone()))
+    }
+
+    fn clone_from(&mut self, source: &Self) {
+        *self = source.clone()
+    }
+}
+
 struct StackStackInner<T: Sized> {
     next: StackStack<T>,
     count: usize,
     stack: Stack<T>,
 }
 
+impl<T: Clone> Clone for StackStackInner<T> {
+    fn clone(&self) -> Self {
+        StackStackInner{
+            next: self.next.clone(),
+            count: self.count,
+            stack: self.stack.clone()
+        }
+    }
+
+    fn clone_from(&mut self, source: &Self) {
+        *self = source.clone()
+    }
+}
+
 pub struct StackStack<T: Sized> (Rc<Option<StackStackInner<T>>>);
 
+impl<T: Clone> Clone for StackStack<T> {
+    fn clone(&self) -> Self {
+        StackStack(Rc::from((*self.0).clone()))
+    }
+
+    fn clone_from(&mut self, source: &Self) {
+        *self = source.clone()
+    }
+}
+
 impl<T> From<T> for StackInner<T> {
     fn from(t: T) -> StackInner<T> {
         StackInner {