do loop.

tests/while_loop.rs

@@ -24,3 +24,28 @@ fn test_while() -> Result<(), Box<EvalAltResult>> {
 
     Ok(())
 }
+
+#[test]
+fn test_do() -> Result<(), Box<EvalAltResult>> {
+    let engine = Engine::new();
+
+    assert_eq!(
+        engine.eval::<INT>(
+            r"
+                let x = 0;
+
+                do {
+                    x += 1;
+                    if x > 5 { break; }
+                    if x > 3 { continue; }
+                    x += 3;
+                } while x < 10;
+                
+                x
+        ",
+        )?,
+        6
+    );
+
+    Ok(())
+}