diff --git a/src/engine.rs b/src/engine.rs
index 5bb26d2c..c4c68b87 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -1314,405 +1314,3 @@ impl Engine {
         engine
     }
 }
-
-
-#[test]
-fn test_number_literal() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<i64>("65") {
-        assert_eq!(result, 65);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_chars() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<char>("'y'") {
-        assert_eq!(result, 'y');
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval::<char>("'\\u2764'") {
-        assert_eq!(result, '❤');
-    } else {
-        assert!(false);
-    }
-
-    match engine.eval::<char>("''") {
-        Err(_) => (),
-        _ => assert!(false),
-    }
-}
-
-#[test]
-fn test_ops() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<i64>("60 + 5") {
-        assert_eq!(result, 65);
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval::<i64>("(1 + 2) * (6 - 4) / 2") {
-        assert_eq!(result, 3);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_mismatched_op() {
-    let mut engine = Engine::new();
-
-    match engine.eval::<i64>("60 + \"hello\"") {
-        Err(EvalAltResult::ErrorFunctionArgMismatch) => (),
-        _ => assert!(false),
-    }
-}
-
-#[test]
-fn test_bool_op1() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<bool>("true && (false || true)") {
-        assert_eq!(result, true);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_bool_op2() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<bool>("false && (false || true)") {
-        assert_eq!(result, false);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_op_prec() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<i64>("let x = 0; if x == 10 || true { x = 1} x") {
-        assert_eq!(result, 1);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_if() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<i64>("if true { 55 }") {
-        assert_eq!(result, 55);
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval::<i64>("if false { 55 } else { 44 }") {
-        assert_eq!(result, 44);
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval::<i64>("if true { 55 } else { 44 }") {
-        assert_eq!(result, 55);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_while() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<i64>("let x = 0; while x < 10 { x = x + 1; if x > 5 { \
-                                            break } } x") {
-        assert_eq!(result, 6);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_var_scope() {
-    let mut engine = Engine::new();
-    let mut scope: Scope = Vec::new();
-
-    if let Ok(_) = engine.eval_with_scope::<()>(&mut scope, "let x = 4 + 5") {
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval_with_scope::<i64>(&mut scope, "x") {
-        assert_eq!(result, 9);
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(_) = engine.eval_with_scope::<()>(&mut scope, "x = x + 1; x = x + 2;") {
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval_with_scope::<i64>(&mut scope, "x") {
-        assert_eq!(result, 12);
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(_) = engine.eval_with_scope::<()>(&mut scope, "{let x = 3}") {
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval_with_scope::<i64>(&mut scope, "x") {
-        assert_eq!(result, 12);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_method_call() {
-    #[derive(Clone)]
-    struct TestStruct {
-        x: i64,
-    }
-
-    impl TestStruct {
-        fn update(&mut self) {
-            self.x += 1000;
-        }
-
-        fn new() -> TestStruct {
-            TestStruct { x: 1 }
-        }
-    }
-
-    let mut engine = Engine::new();
-
-    engine.register_type::<TestStruct>();
-
-    engine.register_fn("update", TestStruct::update);
-    engine.register_fn("new_ts", TestStruct::new);
-
-    if let Ok(result) = engine.eval::<TestStruct>("let x = new_ts(); x.update(); x") {
-        assert_eq!(result.x, 1001);
-    } else {
-        assert!(false);
-    }
-
-}
-
-#[test]
-fn test_get_set() {
-    #[derive(Clone)]
-    struct TestStruct {
-        x: i64,
-    }
-
-    impl TestStruct {
-        fn get_x(&mut self) -> i64 {
-            self.x
-        }
-
-        fn set_x(&mut self, new_x: i64) {
-            self.x = new_x;
-        }
-
-        fn new() -> TestStruct {
-            TestStruct { x: 1 }
-        }
-    }
-
-    let mut engine = Engine::new();
-
-    engine.register_type::<TestStruct>();
-
-    engine.register_get_set("x", TestStruct::get_x, TestStruct::set_x);
-    engine.register_fn("new_ts", TestStruct::new);
-
-    if let Ok(result) = engine.eval::<i64>("let a = new_ts(); a.x = 500; a.x") {
-        assert_eq!(result, 500);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_big_get_set() {
-    #[derive(Clone)]
-    struct TestChild {
-        x: i64,
-    }
-
-    impl TestChild {
-        fn get_x(&mut self) -> i64 {
-            self.x
-        }
-
-        fn set_x(&mut self, new_x: i64) {
-            self.x = new_x;
-        }
-
-        fn new() -> TestChild {
-            TestChild { x: 1 }
-        }
-    }
-
-    #[derive(Clone)]
-    struct TestParent {
-        child: TestChild,
-    }
-
-    impl TestParent {
-        fn get_child(&mut self) -> TestChild {
-            self.child.clone()
-        }
-
-        fn set_child(&mut self, new_child: TestChild) {
-            self.child = new_child;
-        }
-
-        fn new() -> TestParent {
-            TestParent { child: TestChild::new() }
-        }
-    }
-
-    let mut engine = Engine::new();
-
-    engine.register_type::<TestChild>();
-    engine.register_type::<TestParent>();
-
-    engine.register_get_set("x", TestChild::get_x, TestChild::set_x);
-    engine.register_get_set("child", TestParent::get_child, TestParent::set_child);
-
-    engine.register_fn("new_tp", TestParent::new);
-
-    if let Ok(result) = engine.eval::<i64>("let a = new_tp(); a.child.x = 500; a.child.x") {
-        assert_eq!(result, 500);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_internal_fn() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<i64>("fn addme(a, b) { a+b } addme(3, 4)") {
-        assert_eq!(result, 7);
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval::<i64>("fn bob() { return 4; 5 } bob()") {
-        assert_eq!(result, 4);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_big_internal_fn() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<i64>("fn mathme(a, b, c, d, e, f) { a - b * c + d * e - f \
-                                            } mathme(100, 5, 2, 9, 6, 32)") {
-        assert_eq!(result, 112);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_string() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<String>("\"Test string: \\u2764\"") {
-        assert_eq!(result, "Test string: ❤");
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval::<String>("\"foo\" + \"bar\"") {
-        assert_eq!(result, "foobar");
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_arrays() {
-    let mut engine = Engine::new();
-
-    if let Ok(result) = engine.eval::<i64>("let x = [1, 2, 3]; x[1]") {
-        assert_eq!(result, 2);
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval::<i64>("let y = [1, 2, 3]; y[1] = 5; y[1]") {
-        assert_eq!(result, 5);
-    } else {
-        assert!(false);
-    }
-}
-
-#[test]
-fn test_array_with_structs() {
-    #[derive(Clone)]
-    struct TestStruct {
-        x: i64,
-    }
-
-    impl TestStruct {
-        fn update(&mut self) {
-            self.x += 1000;
-        }
-
-        fn get_x(&mut self) -> i64 {
-            self.x
-        }
-
-        fn set_x(&mut self, new_x: i64) {
-            self.x = new_x;
-        }
-
-        fn new() -> TestStruct {
-            TestStruct { x: 1 }
-        }
-    }
-
-    let mut engine = Engine::new();
-
-    engine.register_type::<TestStruct>();
-
-    engine.register_get_set("x", TestStruct::get_x, TestStruct::set_x);
-    engine.register_fn("update", TestStruct::update);
-    engine.register_fn("new_ts", TestStruct::new);
-
-    if let Ok(result) = engine.eval::<i64>("let a = [new_ts()]; a[0].x") {
-        assert_eq!(result, 1);
-    } else {
-        assert!(false);
-    }
-
-    if let Ok(result) = engine.eval::<i64>("let a = [new_ts()]; a[0].x = 100; a[0].update(); \
-                                            a[0].x") {
-        assert_eq!(result, 1100);
-    } else {
-        assert!(false);
-    }
-}
diff --git a/src/lib.rs b/src/lib.rs
index 1dbf3a78..0b9cc5ca 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -11,5 +11,8 @@ mod engine;
 mod fn_register;
 mod parser;
 
+#[cfg(test)]
+mod tests;
+
 pub use engine::{Engine, Scope};
 pub use fn_register::FnRegister;
diff --git a/src/tests.rs b/src/tests.rs
new file mode 100644
index 00000000..dffed5d7
--- /dev/null
+++ b/src/tests.rs
@@ -0,0 +1,400 @@
+#[test]
+fn test_number_literal() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<i64>("65") {
+        assert_eq!(result, 65);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_chars() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<char>("'y'") {
+        assert_eq!(result, 'y');
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval::<char>("'\\u2764'") {
+        assert_eq!(result, '❤');
+    } else {
+        assert!(false);
+    }
+
+    match engine.eval::<char>("''") {
+        Err(_) => (),
+        _ => assert!(false),
+    }
+}
+
+#[test]
+fn test_ops() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<i64>("60 + 5") {
+        assert_eq!(result, 65);
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval::<i64>("(1 + 2) * (6 - 4) / 2") {
+        assert_eq!(result, 3);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_mismatched_op() {
+    let mut engine = Engine::new();
+
+    match engine.eval::<i64>("60 + \"hello\"") {
+        Err(EvalAltResult::ErrorFunctionArgMismatch) => (),
+        _ => assert!(false),
+    }
+}
+
+#[test]
+fn test_bool_op1() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<bool>("true && (false || true)") {
+        assert_eq!(result, true);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_bool_op2() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<bool>("false && (false || true)") {
+        assert_eq!(result, false);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_op_prec() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<i64>("let x = 0; if x == 10 || true { x = 1} x") {
+        assert_eq!(result, 1);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_if() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<i64>("if true { 55 }") {
+        assert_eq!(result, 55);
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval::<i64>("if false { 55 } else { 44 }") {
+        assert_eq!(result, 44);
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval::<i64>("if true { 55 } else { 44 }") {
+        assert_eq!(result, 55);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_while() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<i64>("let x = 0; while x < 10 { x = x + 1; if x > 5 { \
+                                            break } } x") {
+        assert_eq!(result, 6);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_var_scope() {
+    let mut engine = Engine::new();
+    let mut scope: Scope = Vec::new();
+
+    if let Ok(_) = engine.eval_with_scope::<()>(&mut scope, "let x = 4 + 5") {
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval_with_scope::<i64>(&mut scope, "x") {
+        assert_eq!(result, 9);
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(_) = engine.eval_with_scope::<()>(&mut scope, "x = x + 1; x = x + 2;") {
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval_with_scope::<i64>(&mut scope, "x") {
+        assert_eq!(result, 12);
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(_) = engine.eval_with_scope::<()>(&mut scope, "{let x = 3}") {
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval_with_scope::<i64>(&mut scope, "x") {
+        assert_eq!(result, 12);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_method_call() {
+    #[derive(Clone)]
+    struct TestStruct {
+        x: i64,
+    }
+
+    impl TestStruct {
+        fn update(&mut self) {
+            self.x += 1000;
+        }
+
+        fn new() -> TestStruct {
+            TestStruct { x: 1 }
+        }
+    }
+
+    let mut engine = Engine::new();
+
+    engine.register_type::<TestStruct>();
+
+    engine.register_fn("update", TestStruct::update);
+    engine.register_fn("new_ts", TestStruct::new);
+
+    if let Ok(result) = engine.eval::<TestStruct>("let x = new_ts(); x.update(); x") {
+        assert_eq!(result.x, 1001);
+    } else {
+        assert!(false);
+    }
+
+}
+
+#[test]
+fn test_get_set() {
+    #[derive(Clone)]
+    struct TestStruct {
+        x: i64,
+    }
+
+    impl TestStruct {
+        fn get_x(&mut self) -> i64 {
+            self.x
+        }
+
+        fn set_x(&mut self, new_x: i64) {
+            self.x = new_x;
+        }
+
+        fn new() -> TestStruct {
+            TestStruct { x: 1 }
+        }
+    }
+
+    let mut engine = Engine::new();
+
+    engine.register_type::<TestStruct>();
+
+    engine.register_get_set("x", TestStruct::get_x, TestStruct::set_x);
+    engine.register_fn("new_ts", TestStruct::new);
+
+    if let Ok(result) = engine.eval::<i64>("let a = new_ts(); a.x = 500; a.x") {
+        assert_eq!(result, 500);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_big_get_set() {
+    #[derive(Clone)]
+    struct TestChild {
+        x: i64,
+    }
+
+    impl TestChild {
+        fn get_x(&mut self) -> i64 {
+            self.x
+        }
+
+        fn set_x(&mut self, new_x: i64) {
+            self.x = new_x;
+        }
+
+        fn new() -> TestChild {
+            TestChild { x: 1 }
+        }
+    }
+
+    #[derive(Clone)]
+    struct TestParent {
+        child: TestChild,
+    }
+
+    impl TestParent {
+        fn get_child(&mut self) -> TestChild {
+            self.child.clone()
+        }
+
+        fn set_child(&mut self, new_child: TestChild) {
+            self.child = new_child;
+        }
+
+        fn new() -> TestParent {
+            TestParent { child: TestChild::new() }
+        }
+    }
+
+    let mut engine = Engine::new();
+
+    engine.register_type::<TestChild>();
+    engine.register_type::<TestParent>();
+
+    engine.register_get_set("x", TestChild::get_x, TestChild::set_x);
+    engine.register_get_set("child", TestParent::get_child, TestParent::set_child);
+
+    engine.register_fn("new_tp", TestParent::new);
+
+    if let Ok(result) = engine.eval::<i64>("let a = new_tp(); a.child.x = 500; a.child.x") {
+        assert_eq!(result, 500);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_internal_fn() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<i64>("fn addme(a, b) { a+b } addme(3, 4)") {
+        assert_eq!(result, 7);
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval::<i64>("fn bob() { return 4; 5 } bob()") {
+        assert_eq!(result, 4);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_big_internal_fn() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<i64>("fn mathme(a, b, c, d, e, f) { a - b * c + d * e - f \
+                                            } mathme(100, 5, 2, 9, 6, 32)") {
+        assert_eq!(result, 112);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_string() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<String>("\"Test string: \\u2764\"") {
+        assert_eq!(result, "Test string: ❤");
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval::<String>("\"foo\" + \"bar\"") {
+        assert_eq!(result, "foobar");
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_arrays() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<i64>("let x = [1, 2, 3]; x[1]") {
+        assert_eq!(result, 2);
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval::<i64>("let y = [1, 2, 3]; y[1] = 5; y[1]") {
+        assert_eq!(result, 5);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_array_with_structs() {
+    #[derive(Clone)]
+    struct TestStruct {
+        x: i64,
+    }
+
+    impl TestStruct {
+        fn update(&mut self) {
+            self.x += 1000;
+        }
+
+        fn get_x(&mut self) -> i64 {
+            self.x
+        }
+
+        fn set_x(&mut self, new_x: i64) {
+            self.x = new_x;
+        }
+
+        fn new() -> TestStruct {
+            TestStruct { x: 1 }
+        }
+    }
+
+    let mut engine = Engine::new();
+
+    engine.register_type::<TestStruct>();
+
+    engine.register_get_set("x", TestStruct::get_x, TestStruct::set_x);
+    engine.register_fn("update", TestStruct::update);
+    engine.register_fn("new_ts", TestStruct::new);
+
+    if let Ok(result) = engine.eval::<i64>("let a = [new_ts()]; a[0].x") {
+        assert_eq!(result, 1);
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval::<i64>("let a = [new_ts()]; a[0].x = 100; a[0].update(); \
+                                            a[0].x") {
+        assert_eq!(result, 1100);
+    } else {
+        assert!(false);
+    }
+}