some underflow tests

1 files changed, 31 insertions, 1 deletions

diff --git a/src/forth/vm.rs b/src/forth/vm.rs
index e5973dd..2305393 100644
--- a/src/forth/vm.rs
+++ b/src/forth/vm.rs
@@ -112,7 +112,7 @@ pub struct VM {
     pub ip: InstructionPointer,
 }
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq, Eq)]
 pub enum RuntimeError {
     StackUnderflow,
 }
@@ -596,6 +596,16 @@ mod tests {
     }
 
     #[test]
+    fn opcode_dup_underflow() -> Result<(), RuntimeError> {
+        let wordlist = wl_for(vec![
+            vec![OpCode::Dup],
+        ]);
+        let mut vm = VM::new(wordlist);
+        assert!(vm.run().is_err_and(|e| e == RuntimeError::StackUnderflow));
+        Ok(())
+    }
+
+    #[test]
     fn opcode_swap() -> Result<(), RuntimeError> {
         let wordlist = wl_for(vec![
             vec![OpCode::Num(1), OpCode::Num(2), OpCode::Swap],
@@ -607,6 +617,16 @@ mod tests {
     }
 
     #[test]
+    fn opcode_swap_underflow() -> Result<(), RuntimeError> {
+        let wordlist = wl_for(vec![
+            vec![OpCode::Num(1), OpCode::Swap],
+        ]);
+        let mut vm = VM::new(wordlist);
+        assert!(vm.run().is_err_and(|e| e == RuntimeError::StackUnderflow));
+        Ok(())
+    }
+
+    #[test]
     fn opcode_rot() -> Result<(), RuntimeError> {
         let wordlist = wl_for(vec![
             vec![OpCode::Num(1), OpCode::Num(2), OpCode::Num(3), OpCode::Rot],
@@ -618,6 +638,16 @@ mod tests {
     }
 
     #[test]
+    fn opcode_rot_underflow() -> Result<(), RuntimeError> {
+        let wordlist = wl_for(vec![
+            vec![OpCode::Num(1), OpCode::Num(2), OpCode::Rot],
+        ]);
+        let mut vm = VM::new(wordlist);
+        assert!(vm.run().is_err_and(|e| e == RuntimeError::StackUnderflow));
+        Ok(())
+    }
+
+    #[test]
     fn tif_no_ret() -> Result<(), RuntimeError> {
         let wordlist = wl_for(vec![
             vec![OpCode::Call(1)],