diff --git a/assets/tests/ruby/promise_runtime_error.rb b/assets/tests/ruby/promise_runtime_error.rb
new file mode 100644
index 0000000..48827fc
--- /dev/null
+++ b/assets/tests/ruby/promise_runtime_error.rb
@@ -0,0 +1,5 @@
+def test_func
+  rust_func.and_then do |x|
+    print("abc" + 5)
+  end
+end
diff --git a/assets/tests/ruby/return_via_promise.rb b/assets/tests/ruby/return_via_promise.rb
index dc9d107..c1ec94b 100644
--- a/assets/tests/ruby/return_via_promise.rb
+++ b/assets/tests/ruby/return_via_promise.rb
@@ -3,7 +3,7 @@ $state = {
 }
 
 def test_func
-  # rust_func.and_then do |x|
-  #   $state['x'] = x
-  # end
+  rust_func.and_then do |x|
+    $state['x'] = x
+  end
 end
diff --git a/assets/tests/ruby/side_effects.rb b/assets/tests/ruby/side_effects.rb
new file mode 100644
index 0000000..8b6177d
--- /dev/null
+++ b/assets/tests/ruby/side_effects.rb
@@ -0,0 +1,3 @@
+def test_func
+  spawn_entity
+end
diff --git a/src/runtimes/ruby.rs b/src/runtimes/ruby.rs
index 73eabd9..6700a93 100644
--- a/src/runtimes/ruby.rs
+++ b/src/runtimes/ruby.rs
@@ -331,11 +331,13 @@ impl<T: IntoValue> FuncArgs<'_, RubyValue, RubyRuntime> for Vec<T> {
 
 macro_rules! impl_tuple {
     ($($idx:tt $t:tt),+) => {
-        impl<'a, $($t,)+> FuncArgs<'a, RubyValue, RubyRuntime>
+        impl<'a, $($t: IntoValue,)+> FuncArgs<'a, RubyValue, RubyRuntime>
             for ($($t,)+)
         {
             fn parse(self, _engine: &'a magnus::Ruby) -> Vec<RubyValue> {
-                todo!();
+                vec![
+                    $(RubyValue::new(self.$idx.into_value()), )+
+                ]
             }
         }
     };
diff --git a/tests/tests.rs b/tests/tests.rs
index 49ec68a..950bbd0 100644
--- a/tests/tests.rs
+++ b/tests/tests.rs
@@ -189,7 +189,7 @@ macro_rules! scripting_tests {
         }
 
         #[test]
-        fn test_script_function_gets_called_from_rust_with_heterogenous_params() {
+        fn test_script_function_gets_called_from_rust_with_multiple_params() {
             let mut app = build_test_app();
 
             app.add_scripting::<$runtime>(|_| {});
@@ -225,33 +225,7 @@ macro_rules! scripting_tests {
         }
 
         #[test]
-        fn test_script_function_gets_called_from_rust_with_multiple_params() {
-            let mut app = build_test_app();
-
-            app.add_scripting::<$runtime>(|_| {});
-
-            let entity_id = run_script::<$runtime, _, _>(
-                &mut app,
-                format!(
-                    "tests/{}/script_function_gets_called_from_rust_with_multiple_params.{}",
-                    $script, $extension
-                )
-                .to_string(),
-                |mut scripted_entities: Query<(Entity, &mut <$runtime as Runtime>::ScriptData)>,
-                 scripting_runtime: ResMut<$runtime>| {
-                    let (entity, mut script_data) = scripted_entities.single_mut().unwrap();
-                    scripting_runtime
-                        .call_fn("test_func", &mut script_data, entity, vec![1, 2])
-                        .unwrap();
-                },
-            );
-
-            <$runtime>::assert_state_key_value_i32(&app.world(), entity_id, "a_value", 1i32);
-            <$runtime>::assert_state_key_value_i32(&app.world(), entity_id, "b_value", 2i32);
-        }
-
-        #[test]
-        fn test_call_script_function_that_casues_runtime_error() {
+        fn call_script_function_that_casues_runtime_error() {
             let mut app = build_test_app();
 
             app.add_scripting::<$runtime>(|_| {});
@@ -274,18 +248,14 @@ macro_rules! scripting_tests {
         }
 
         #[test]
-        fn test_call_script_function_that_causes_runtime_error() {
+        fn call_script_function_that_does_not_exist() {
             let mut app = build_test_app();
 
             app.add_scripting::<$runtime>(|_| {});
 
             run_script::<$runtime, _, _>(
                 &mut app,
-                format!(
-                    "tests/{}/call_script_function_that_causes_runtime_error.{}",
-                    $script, $extension
-                )
-                .to_string(),
+                format!("tests/{}/side_effects.{}", $script, $extension).to_string(),
                 |mut scripted_entities: Query<(Entity, &mut <$runtime as Runtime>::ScriptData)>,
                  scripting_runtime: ResMut<$runtime>| {
                     let (entity, mut script_data) = scripted_entities.single_mut().unwrap();
@@ -297,7 +267,7 @@ macro_rules! scripting_tests {
         }
 
         #[test]
-        fn test_script_function_gets_called_from_rust() {
+        fn script_function_gets_called_from_rust() {
             let mut app = build_test_app();
 
             app.add_scripting::<$runtime>(|_| {});
@@ -316,7 +286,7 @@ macro_rules! scripting_tests {
         }
 
         #[test]
-        fn test_return_via_promise() {
+        fn return_via_promise() {
             let mut app = build_test_app();
 
             app.add_scripting::<$runtime>(|runtime| {
@@ -333,7 +303,7 @@ macro_rules! scripting_tests {
         }
 
         #[test]
-        fn test_promise_runtime_error_does_not_panic() {
+        fn promise_runtime_error() {
             let mut app = build_test_app();
 
             app.add_scripting::<$runtime>(|runtime| {
@@ -348,7 +318,7 @@ macro_rules! scripting_tests {
         }
 
         #[test]
-        fn test_side_effects() {
+        fn side_effects() {
             let mut app = build_test_app();
 
             #[derive(Component)]
@@ -374,7 +344,7 @@ macro_rules! scripting_tests {
         }
 
         #[test]
-        fn test_rust_function_gets_called_from_script() {
+        fn rust_function_gets_called_from_script() {
             let mut app = build_test_app();
 
             #[derive(Default, Resource)]
@@ -519,7 +489,9 @@ mod ruby_tests {
             value: &str,
         ) {
             let runtime = world.get_resource::<RubyRuntime>().unwrap();
-            runtime.with_engine(|engine| {
+            let key = key.to_string();
+            let value = value.to_string();
+            runtime.with_engine_thread(move |engine| {
                 let state: magnus::value::Value = engine.eval("$state").unwrap();
                 let res: String = state.funcall_public("[]", (key,)).unwrap();
                 assert_eq!(res, value);