From 518a71d24a65c0ae173674d9160fccd6181e8901 Mon Sep 17 00:00:00 2001
From: Reid 'arrdem' McKenzie <me@arrdem.com>
Date: Sun, 18 Dec 2022 12:22:06 -0700
Subject: [PATCH] Unittests on the stack; fix byte order & round-tripping

---
 src/stack.rs | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 83 insertions(+), 1 deletion(-)

diff --git a/src/stack.rs b/src/stack.rs
index d3bfe37..aa37554 100644
--- a/src/stack.rs
+++ b/src/stack.rs
@@ -34,7 +34,7 @@ impl Stack {
         if self.idx > 254 {
             Err(StackError::StackOverflow)
         } else {
-            val.to_le_bytes().map(|x| self.push1(x).ok());
+            val.to_be_bytes().map(|x| self.push1(x).ok());
             Ok(())
         }
     }
@@ -63,6 +63,7 @@ impl Stack {
         } else {
             let high = self.buff[idx as usize] as u16;
             let low = self.buff[(idx + 1) as usize] as u16;
+            println!("idx {}; high {:#02x}; low {:#02x};", idx, high, low);
             Ok((high << 8) + low)
         }
     }
@@ -91,3 +92,84 @@ impl Stack {
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod stack_test {
+    use super::*;
+
+    #[test]
+    fn test_push_pop() {
+        let mut s = Stack::new();
+        match s.push1(0xFF) {
+            Ok(()) => (),
+            Err(_) => assert!(false, "pushing stack of size 0 errored"),
+        }
+        assert_eq!(s.idx, 1);
+
+        match s.peek1() {
+            Ok(val) => assert_eq!(val, 0xFF),
+            Err(_) => assert!(false, "popping stack of size 1 errored"),
+        }
+        assert_eq!(s.idx, 1);
+
+        match s.pop1() {
+            Ok(val) => assert_eq!(val, 0xFF),
+            Err(_) => assert!(false, "popping stack of size 1 errored"),
+        }
+        assert_eq!(s.idx, 0);
+    }
+
+    #[test]
+    fn test_push2_pop2() {
+        let mut s = Stack::new();
+        match s.push2(0xFF00) {
+            Ok(()) => (),
+            Err(_) => assert!(false, "pushing stack of size 0 errored"),
+        }
+        assert_eq!(s.idx, 2);
+
+        match s.peek2() {
+            Ok(val) => assert_eq!(val, 0xFF00),
+            Err(_) => assert!(false, "peek2 stack of size 2 errored"),
+        }
+        assert_eq!(s.idx, 2);
+
+        match s.pop2() {
+            Ok(val) => assert_eq!(val, 0xFF00),
+            Err(_) => assert!(false, "peek2 stack of size 2 errored"),
+        }
+        assert_eq!(s.idx, 0);
+    }
+
+    #[test]
+    fn test_push2_pop1_pop1() {
+        let mut s = Stack::new();
+        match s.push2(0xFF00) {
+            Ok(()) => (),
+            Err(_) => assert!(false, "pushing stack of size 0 errored"),
+        }
+        assert_eq!(s.idx, 2);
+
+        match s.pop1() {
+            Ok(val) => assert_eq!(val, 0x00),
+            Err(_) => assert!(false, "peek1 stack of size 2 errored"),
+        }
+        assert_eq!(s.idx, 1);
+
+        match s.pop1() {
+            Ok(val) => assert_eq!(val, 0xFF),
+            Err(_) => assert!(false, "peek1 stack of size 2 errored"),
+        }
+        assert_eq!(s.idx, 0);
+    }
+
+    #[test]
+    fn test_pop_empty() {
+        let mut s = Stack::new();
+        match s.pop1() {
+            Ok(_) => assert!(false, "popping stack of size 0 succeeded"),
+            Err(StackError::StackUnderflow) => (),
+            Err(_) => assert!(false, "poppoing stack of size 0 didn't underflow"),
+        }
+    }
+}