Add plugins test.

tests/plugins.rs

@@ -0,0 +1,24 @@
+use rhai::{export_module, exported_module};
+use rhai::{Engine, EvalAltResult, INT};
+
+#[export_module]
+pub mod array_package {
+    use rhai::{Array, INT};
+
+    pub fn len(array: &mut Array, mul: INT) -> INT {
+        (array.len() as INT) * mul
+    }
+}
+
+#[test]
+fn test_plugins() -> Result<(), Box<EvalAltResult>> {
+    let mut engine = Engine::new();
+
+    let m = exported_module!(array_package);
+
+    engine.load_package(m.into());
+
+    assert_eq!(engine.eval::<INT>("let a = [1, 2, 3]; a.len(2)")?, 6);
+
+    Ok(())
+}