Add try-catch.

tests/throw.rs

@@ -1,4 +1,4 @@
-use rhai::{Engine, EvalAltResult};
+use rhai::{Engine, EvalAltResult, INT};
 
 #[test]
 fn test_throw() {
@@ -14,3 +14,27 @@ fn test_throw() {
         EvalAltResult::ErrorRuntime(s, _) if s.is::<()>()
     ));
 }
+
+#[test]
+fn test_try_catch() -> Result<(), Box<EvalAltResult>> {
+    let engine = Engine::new();
+
+    assert_eq!(
+        engine.eval::<INT>("try { throw 42; } catch (x) { return x; }")?,
+        42
+    );
+
+    assert_eq!(
+        engine.eval::<INT>("try { throw 42; } catch { return 123; }")?,
+        123
+    );
+
+    assert!(matches!(
+        *engine
+            .eval::<()>("try { 42/0; } catch { throw; }")
+            .expect_err("expects error"),
+        EvalAltResult::ErrorArithmetic(_, _)
+    ));
+
+    Ok(())
+}