diff --git a/napi-derive/src/lib.rs b/napi-derive/src/lib.rs
index 963f92bc..afd9d3c6 100644
--- a/napi-derive/src/lib.rs
+++ b/napi-derive/src/lib.rs
@@ -112,7 +112,7 @@ pub fn js_function(attr: TokenStream, input: TokenStream) -> TokenStream {
       }
 
       let mut env = Env::from_raw(raw_env);
-      let call_ctx = CallContext::new(&mut env, raw_this, &raw_args, #arg_len_span, argc as usize);
+      let call_ctx = CallContext::new(&mut env, cb_info, raw_this, &raw_args, #arg_len_span, argc as usize);
       let result = call_ctx.and_then(|ctx| {
         match panic::catch_unwind(AssertUnwindSafe(move || #new_fn_name(ctx))) {
           Ok(result) => result,
diff --git a/napi/src/call_context.rs b/napi/src/call_context.rs
index f8cccff1..1f10f99f 100644
--- a/napi/src/call_context.rs
+++ b/napi/src/call_context.rs
@@ -1,8 +1,12 @@
+use std::ptr;
+
+use crate::error::check_status;
 use crate::{sys, Either, Env, Error, JsUndefined, JsUnknown, NapiValue, Result, Status};
 
 pub struct CallContext<'env, T: NapiValue = JsUnknown> {
   pub env: &'env Env,
   pub this: T,
+  callback_info: sys::napi_callback_info,
   args: &'env [sys::napi_value],
   arg_len: usize,
   actual_arg_length: usize,
@@ -12,6 +16,7 @@ impl<'env, T: NapiValue> CallContext<'env, T> {
   #[inline]
   pub fn new(
     env: &'env Env,
+    callback_info: sys::napi_callback_info,
     this: sys::napi_value,
     args: &'env [sys::napi_value],
     arg_len: usize,
@@ -19,6 +24,7 @@ impl<'env, T: NapiValue> CallContext<'env, T> {
   ) -> Result<Self> {
     Ok(Self {
       env,
+      callback_info,
       this: T::from_raw(env.0, this)?,
       args,
       arg_len,
@@ -53,4 +59,13 @@ impl<'env, T: NapiValue> CallContext<'env, T> {
       }
     }
   }
+
+  pub fn get_new_target<V>(&self) -> Result<V>
+  where
+    V: NapiValue,
+  {
+    let mut value = ptr::null_mut();
+    check_status(unsafe { sys::napi_get_new_target(self.env.0, self.callback_info, &mut value) })?;
+    V::from_raw(self.env.0, value)
+  }
 }
diff --git a/napi/src/env.rs b/napi/src/env.rs
index ba2a2270..46594a9d 100644
--- a/napi/src/env.rs
+++ b/napi/src/env.rs
@@ -379,12 +379,12 @@ impl Env {
     &self,
     name: &str,
     constructor_cb: Callback,
-    properties: Vec<Property>,
+    properties: &mut [Property],
   ) -> Result<JsFunction> {
     let mut raw_result = ptr::null_mut();
     let raw_properties = properties
-      .into_iter()
-      .map(|prop| prop.into_raw(self))
+      .iter_mut()
+      .map(|prop| prop.as_raw(self.0))
       .collect::<Result<Vec<sys::napi_property_descriptor>>>()?;
 
     check_status(unsafe {
diff --git a/napi/src/js_values/class_property.rs b/napi/src/js_values/class_property.rs
index 2f57eea6..c421929b 100644
--- a/napi/src/js_values/class_property.rs
+++ b/napi/src/js_values/class_property.rs
@@ -1,17 +1,41 @@
+use std::convert::From;
+use std::ffi::CString;
 use std::ptr;
 
-use crate::{sys, Callback, Env, NapiValue, Result};
+use crate::{error::check_status, sys, Callback, NapiValue, Result};
 
-#[derive(Debug)]
-pub struct Property {
-  name: String,
-  raw_descriptor: sys::napi_property_descriptor,
+#[derive(Debug, Clone, Copy)]
+pub struct Property<'env> {
+  name: &'env str,
+  pub(crate) raw_descriptor: sys::napi_property_descriptor,
 }
 
-impl Property {
-  pub fn new(name: &str) -> Self {
+#[repr(u32)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub enum PropertyAttributes {
+  Default = sys::napi_property_attributes::napi_default as _,
+  Writable = sys::napi_property_attributes::napi_writable as _,
+  Enumerable = sys::napi_property_attributes::napi_enumerable as _,
+  Configurable = sys::napi_property_attributes::napi_configurable as _,
+  Static = sys::napi_property_attributes::napi_static as _,
+}
+
+impl From<PropertyAttributes> for sys::napi_property_attributes {
+  fn from(value: PropertyAttributes) -> Self {
+    match value {
+      PropertyAttributes::Default => sys::napi_property_attributes::napi_default,
+      PropertyAttributes::Writable => sys::napi_property_attributes::napi_writable,
+      PropertyAttributes::Enumerable => sys::napi_property_attributes::napi_enumerable,
+      PropertyAttributes::Configurable => sys::napi_property_attributes::napi_configurable,
+      PropertyAttributes::Static => sys::napi_property_attributes::napi_static,
+    }
+  }
+}
+
+impl<'env> Property<'env> {
+  pub fn new(name: &'env str) -> Self {
     Property {
-      name: String::from(name),
+      name,
       raw_descriptor: sys::napi_property_descriptor {
         utf8name: ptr::null_mut(),
         name: ptr::null_mut(),
@@ -40,8 +64,27 @@ impl Property {
     self
   }
 
-  pub(crate) fn into_raw(mut self, env: &Env) -> Result<sys::napi_property_descriptor> {
-    self.raw_descriptor.name = env.create_string(&self.name)?.raw_value();
+  pub fn with_setter(mut self, callback: Callback) -> Self {
+    self.raw_descriptor.setter = Some(callback);
+    self
+  }
+
+  pub fn with_property_attributes(mut self, attributes: PropertyAttributes) {
+    self.raw_descriptor.attributes = attributes.into();
+  }
+
+  pub(crate) fn as_raw(&mut self, env: sys::napi_env) -> Result<sys::napi_property_descriptor> {
+    let string_value = CString::new(self.name)?;
+    let mut result = ptr::null_mut();
+    check_status(unsafe {
+      sys::napi_create_string_utf8(
+        env,
+        string_value.as_ptr(),
+        self.name.len() as _,
+        &mut result,
+      )
+    })?;
+    self.raw_descriptor.name = result;
     Ok(self.raw_descriptor)
   }
 }
diff --git a/napi/src/js_values/de.rs b/napi/src/js_values/de.rs
index 2026926d..a565448a 100644
--- a/napi/src/js_values/de.rs
+++ b/napi/src/js_values/de.rs
@@ -122,7 +122,7 @@ impl<'x, 'de, 'env> serde::de::Deserializer<'x> for &'de mut De<'env> {
             ),
           ))
         } else {
-          let key = properties.get_index::<JsString>(0)?;
+          let key = properties.get_element::<JsString>(0)?;
           let value: JsUnknown = js_object.get_property(&key)?;
           visitor.visit_enum(JsEnumAccess::new(key.as_str()?.to_owned(), Some(&value.0)))
         }
@@ -289,7 +289,7 @@ impl<'de, 'env> SeqAccess<'de> for JsArrayAccess<'env> {
     if self.idx >= self.len {
       return Ok(None);
     }
-    let v = self.input.get_index::<JsUnknown>(self.idx)?;
+    let v = self.input.get_element::<JsUnknown>(self.idx)?;
     self.idx += 1;
 
     let mut de = De(&v.0);
@@ -331,7 +331,7 @@ impl<'de, 'env> MapAccess<'de> for JsObjectAccess<'env> {
       return Ok(None);
     }
 
-    let prop_name = self.properties.get_index::<JsUnknown>(self.idx)?;
+    let prop_name = self.properties.get_element::<JsUnknown>(self.idx)?;
 
     let mut de = De(&prop_name.0);
     seed.deserialize(&mut de).map(Some)
@@ -347,7 +347,7 @@ impl<'de, 'env> MapAccess<'de> for JsObjectAccess<'env> {
         format!("Index:{} out of range: {}", self.property_len, self.idx),
       ));
     }
-    let prop_name = self.properties.get_index::<JsString>(self.idx)?;
+    let prop_name = self.properties.get_element::<JsString>(self.idx)?;
     let value: JsUnknown = self.value.get_property(&prop_name)?;
 
     self.idx += 1;
diff --git a/napi/src/js_values/function.rs b/napi/src/js_values/function.rs
index c3497efa..a2190a3d 100644
--- a/napi/src/js_values/function.rs
+++ b/napi/src/js_values/function.rs
@@ -42,7 +42,7 @@ impl JsFunction {
       raw_args[i] = arg.0.value;
     }
     let mut return_value = ptr::null_mut();
-    let status = unsafe {
+    check_status(unsafe {
       sys::napi_call_function(
         self.0.env,
         raw_this,
@@ -51,8 +51,7 @@ impl JsFunction {
         &raw_args[0],
         &mut return_value,
       )
-    };
-    check_status(status)?;
+    })?;
 
     JsUnknown::from_raw(self.0.env, return_value)
   }
diff --git a/napi/src/js_values/object.rs b/napi/src/js_values/object.rs
index 4e4cdba3..e4731a7e 100644
--- a/napi/src/js_values/object.rs
+++ b/napi/src/js_values/object.rs
@@ -3,37 +3,35 @@ use std::ptr;
 
 use super::Value;
 use crate::error::check_status;
-use crate::{sys, Env, Error, JsBuffer, JsNumber, JsString, NapiValue, Result, Status};
+use crate::{sys, Error, JsString, NapiValue, Property, Result, Status};
 
 #[derive(Debug)]
 pub struct JsObject(pub(crate) Value);
 
 impl JsObject {
-  pub fn set_property<V: NapiValue>(&mut self, key: JsString, value: V) -> Result<()> {
-    let status =
-      unsafe { sys::napi_set_property(self.0.env, self.0.value, key.0.value, value.raw_value()) };
-    check_status(status)?;
-    Ok(())
-  }
-
-  pub fn set_number_indexed_property<V: NapiValue>(
-    &mut self,
-    key: JsNumber,
-    value: V,
-  ) -> Result<()> {
+  pub fn set_property<V>(&mut self, key: JsString, value: V) -> Result<()>
+  where
+    V: NapiValue,
+  {
     check_status(unsafe {
       sys::napi_set_property(self.0.env, self.0.value, key.0.value, value.raw_value())
     })
   }
 
-  pub fn set_named_property<T: NapiValue>(&mut self, name: &str, value: T) -> Result<()> {
+  pub fn set_named_property<T>(&mut self, name: &str, value: T) -> Result<()>
+  where
+    T: NapiValue,
+  {
     let key = CString::new(name)?;
     check_status(unsafe {
       sys::napi_set_named_property(self.0.env, self.0.value, key.as_ptr(), value.raw_value())
     })
   }
 
-  pub fn get_named_property<T: NapiValue>(&self, name: &str) -> Result<T> {
+  pub fn get_named_property<T>(&self, name: &str) -> Result<T>
+  where
+    T: NapiValue,
+  {
     let key = CString::new(name)?;
     let mut raw_value = ptr::null_mut();
     check_status(unsafe {
@@ -42,7 +40,66 @@ impl JsObject {
     T::from_raw(self.0.env, raw_value)
   }
 
-  pub fn get_property<K: NapiValue, T: NapiValue>(&self, key: &K) -> Result<T> {
+  pub fn has_named_property(&self, name: &str) -> Result<bool> {
+    let mut result = false;
+    let key = CString::new(name)?;
+    check_status(unsafe {
+      sys::napi_has_named_property(self.0.env, self.0.value, key.as_ptr(), &mut result)
+    })?;
+    Ok(result)
+  }
+
+  pub fn has_own_property(&self, key: &str) -> Result<bool> {
+    let mut result = false;
+    let string = CString::new(key)?;
+    let mut js_key = ptr::null_mut();
+    check_status(unsafe {
+      sys::napi_create_string_utf8(self.0.env, string.as_ptr(), key.len() as _, &mut js_key)
+    })?;
+    check_status(unsafe {
+      sys::napi_has_own_property(self.0.env, self.0.value, js_key, &mut result)
+    })?;
+    Ok(result)
+  }
+
+  pub fn has_own_property_js<K>(&self, key: K) -> Result<bool>
+  where
+    K: NapiValue,
+  {
+    let mut result = false;
+    check_status(unsafe {
+      sys::napi_has_own_property(self.0.env, self.0.value, key.raw_value(), &mut result)
+    })?;
+    Ok(result)
+  }
+
+  pub fn has_property(&self, name: &str) -> Result<bool> {
+    let string = CString::new(name)?;
+    let mut js_key = ptr::null_mut();
+    let mut result = false;
+    check_status(unsafe {
+      sys::napi_create_string_utf8(self.0.env, string.as_ptr(), name.len() as _, &mut js_key)
+    })?;
+    check_status(unsafe { sys::napi_has_property(self.0.env, self.0.value, js_key, &mut result) })?;
+    Ok(result)
+  }
+
+  pub fn has_property_js<K>(&self, name: K) -> Result<bool>
+  where
+    K: NapiValue,
+  {
+    let mut result = false;
+    check_status(unsafe {
+      sys::napi_has_property(self.0.env, self.0.value, name.raw_value(), &mut result)
+    })?;
+    Ok(result)
+  }
+
+  pub fn get_property<K, T>(&self, key: &K) -> Result<T>
+  where
+    K: NapiValue,
+    T: NapiValue,
+  {
     let mut raw_value = ptr::null_mut();
     check_status(unsafe {
       sys::napi_get_property(self.0.env, self.0.value, key.raw_value(), &mut raw_value)
@@ -50,18 +107,52 @@ impl JsObject {
     T::from_raw(self.0.env, raw_value)
   }
 
-  pub fn get_property_names<T: NapiValue>(&self) -> Result<T> {
+  pub fn get_property_names<T>(&self) -> Result<T>
+  where
+    T: NapiValue,
+  {
     let mut raw_value = ptr::null_mut();
     let status = unsafe { sys::napi_get_property_names(self.0.env, self.0.value, &mut raw_value) };
     check_status(status)?;
     T::from_raw(self.0.env, raw_value)
   }
 
-  pub fn set_index<T: NapiValue>(&mut self, index: usize, value: T) -> Result<()> {
-    self.set_number_indexed_property(Env::from_raw(self.0.env).create_int64(index as i64)?, value)
+  pub fn get_prototype<T>(&self) -> Result<T>
+  where
+    T: NapiValue,
+  {
+    let mut result = ptr::null_mut();
+    check_status(unsafe { sys::napi_get_prototype(self.0.env, self.0.value, &mut result) })?;
+    T::from_raw(self.0.env, result)
   }
 
-  pub fn get_index<T: NapiValue>(&self, index: u32) -> Result<T> {
+  pub fn set_element<T>(&mut self, index: u32, value: T) -> Result<()>
+  where
+    T: NapiValue,
+  {
+    check_status(unsafe {
+      sys::napi_set_element(self.0.env, self.0.value, index, value.raw_value())
+    })
+  }
+
+  pub fn has_element(&self, index: u32) -> Result<bool> {
+    let mut result = false;
+    check_status(unsafe { sys::napi_has_element(self.0.env, self.0.value, index, &mut result) })?;
+    Ok(result)
+  }
+
+  pub fn delete_element<T>(&mut self, index: u32) -> Result<bool> {
+    let mut result = false;
+    check_status(unsafe {
+      sys::napi_delete_element(self.0.env, self.0.value, index, &mut result)
+    })?;
+    Ok(result)
+  }
+
+  pub fn get_element<T>(&self, index: u32) -> Result<T>
+  where
+    T: NapiValue,
+  {
     let mut raw_value = ptr::null_mut();
     check_status(unsafe {
       sys::napi_get_element(self.0.env, self.0.value, index, &mut raw_value)
@@ -69,6 +160,21 @@ impl JsObject {
     T::from_raw(self.0.env, raw_value)
   }
 
+  pub fn define_properties(&mut self, properties: &mut [Property]) -> Result<()> {
+    check_status(unsafe {
+      sys::napi_define_properties(
+        self.0.env,
+        self.0.value,
+        properties.len() as _,
+        properties
+          .iter_mut()
+          .map(|property| property.as_raw(self.0.env))
+          .collect::<Result<Vec<sys::napi_property_descriptor>>>()?
+          .as_ptr(),
+      )
+    })
+  }
+
   pub fn is_array(&self) -> Result<bool> {
     let mut is_array = false;
     check_status(unsafe { sys::napi_is_array(self.0.env, self.0.value, &mut is_array) })?;
@@ -81,10 +187,6 @@ impl JsObject {
     Ok(is_buffer)
   }
 
-  pub fn to_buffer(&self) -> Result<JsBuffer> {
-    JsBuffer::from_raw(self.0.env, self.0.value)
-  }
-
   pub fn get_array_length(&self) -> Result<u32> {
     if self.is_array()? != true {
       return Err(Error::new(
diff --git a/napi/src/js_values/ser.rs b/napi/src/js_values/ser.rs
index aff74e06..3552c106 100644
--- a/napi/src/js_values/ser.rs
+++ b/napi/src/js_values/ser.rs
@@ -310,8 +310,8 @@ impl ser::SerializeSeq for SeqSerializer {
     T: Serialize,
   {
     let env = Env::from_raw(self.array.0.env);
-    self.array.set_index(
-      self.current_index,
+    self.array.set_element(
+      self.current_index as _,
       JsUnknown(value.serialize(Ser::new(&env))?),
     )?;
     self.current_index = self.current_index + 1;
@@ -334,8 +334,8 @@ impl ser::SerializeTuple for SeqSerializer {
     T: Serialize,
   {
     let env = Env::from_raw(self.array.0.env);
-    self.array.set_index(
-      self.current_index,
+    self.array.set_element(
+      self.current_index as _,
       JsUnknown(value.serialize(Ser::new(&env))?),
     )?;
     self.current_index = self.current_index + 1;
@@ -359,8 +359,8 @@ impl ser::SerializeTupleStruct for SeqSerializer {
     T: Serialize,
   {
     let env = Env::from_raw(self.array.0.env);
-    self.array.set_index(
-      self.current_index,
+    self.array.set_element(
+      self.current_index as _,
       JsUnknown(value.serialize(Ser::new(&env))?),
     )?;
     self.current_index = self.current_index + 1;
@@ -384,8 +384,8 @@ impl ser::SerializeTupleVariant for SeqSerializer {
     T: Serialize,
   {
     let env = Env::from_raw(self.array.0.env);
-    self.array.set_index(
-      self.current_index,
+    self.array.set_element(
+      self.current_index as _,
       JsUnknown(value.serialize(Ser::new(&env))?),
     )?;
     self.current_index = self.current_index + 1;
diff --git a/test_module/__test__/object.spec.ts b/test_module/__test__/object.spec.ts
new file mode 100644
index 00000000..b054a642
--- /dev/null
+++ b/test_module/__test__/object.spec.ts
@@ -0,0 +1,39 @@
+import test from 'ava'
+
+const bindings = require('../index.node')
+
+test('setProperty', (t) => {
+  const obj = {}
+  const key = 'jsPropertyKey'
+  bindings.testSetProperty(obj, key)
+  t.snapshot(obj[key])
+})
+
+test('setNamedProperty', (t) => {
+  const obj = {}
+  const property = Symbol('JsSymbol')
+  bindings.testSetNamedProperty(obj, property)
+  const keys = Object.keys(obj)
+  const [key] = keys
+  t.is(keys.length, 1)
+  t.snapshot(key)
+  t.is(obj[key], property)
+})
+
+test('testGetNamedProperty', (t) => {
+  const obj = {
+    p: Symbol('JsSymbol'),
+  }
+  t.is(bindings.testGetNamedProperty(obj), obj.p)
+})
+
+test('testHasNamedProperty', (t) => {
+  const obj = {
+    a: 1,
+    b: undefined,
+  }
+
+  t.true(bindings.testHasNamedProperty(obj, 'a'))
+  t.true(bindings.testHasNamedProperty(obj, 'b'))
+  t.false(bindings.testHasNamedProperty(obj, 'c'))
+})
diff --git a/test_module/__test__/object.spec.ts.md b/test_module/__test__/object.spec.ts.md
new file mode 100644
index 00000000..ae162d53
--- /dev/null
+++ b/test_module/__test__/object.spec.ts.md
@@ -0,0 +1,17 @@
+# Snapshot report for `test_module/__test__/object.spec.ts`
+
+The actual snapshot is saved in `object.spec.ts.snap`.
+
+Generated by [AVA](https://avajs.dev).
+
+## setProperty
+
+> Snapshot 1
+
+    'Rust object property'
+
+## setNamedProperty
+
+> Snapshot 1
+
+    'RustPropertyKey'
diff --git a/test_module/__test__/object.spec.ts.snap b/test_module/__test__/object.spec.ts.snap
new file mode 100644
index 00000000..a3727419
Binary files /dev/null and b/test_module/__test__/object.spec.ts.snap differ
diff --git a/test_module/src/buffer.rs b/test_module/src/buffer.rs
index a8884054..9b37edf0 100644
--- a/test_module/src/buffer.rs
+++ b/test_module/src/buffer.rs
@@ -1,6 +1,6 @@
 use std::str;
 
-use napi::{CallContext, Error, JsBuffer, JsNumber, JsString, Result, Status};
+use napi::{CallContext, Error, JsBuffer, JsNumber, JsString, Module, Result, Status};
 
 #[js_function(1)]
 pub fn get_buffer_length(ctx: CallContext) -> Result<JsNumber> {
@@ -15,3 +15,9 @@ pub fn buffer_to_string(ctx: CallContext) -> Result<JsString> {
     str::from_utf8(&buffer).map_err(|e| Error::new(Status::StringExpected, format!("{}", e)))?,
   )
 }
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("getBufferLength", get_buffer_length)?;
+  module.create_named_method("bufferToString", buffer_to_string)?;
+  Ok(())
+}
diff --git a/test_module/src/class.rs b/test_module/src/class.rs
index f7e3af8c..ff276a43 100644
--- a/test_module/src/class.rs
+++ b/test_module/src/class.rs
@@ -1,18 +1,20 @@
 use std::convert::TryInto;
 
-use napi::{CallContext, JsFunction, JsNumber, JsObject, JsUndefined, Property, Result};
+use napi::{CallContext, JsFunction, JsNumber, JsObject, JsUndefined, Module, Property, Result};
 
 #[js_function(1)]
-pub fn create_test_class(ctx: CallContext) -> Result<JsFunction> {
+fn create_test_class(ctx: CallContext) -> Result<JsFunction> {
   let add_count_method = Property::new("addCount").with_method(add_count);
-  let properties = vec![add_count_method];
-  ctx
-    .env
-    .define_class("TestClass", test_class_constructor, properties)
+  let mut properties = vec![add_count_method];
+  ctx.env.define_class(
+    "TestClass",
+    test_class_constructor,
+    properties.as_mut_slice(),
+  )
 }
 
 #[js_function(1)]
-pub fn test_class_constructor(mut ctx: CallContext<JsObject>) -> Result<JsUndefined> {
+fn test_class_constructor(mut ctx: CallContext<JsObject>) -> Result<JsUndefined> {
   let count = ctx.get::<JsNumber>(0)?;
   ctx
     .this
@@ -21,7 +23,7 @@ pub fn test_class_constructor(mut ctx: CallContext<JsObject>) -> Result<JsUndefi
 }
 
 #[js_function(1)]
-pub fn add_count(mut ctx: CallContext<JsObject>) -> Result<JsUndefined> {
+fn add_count(mut ctx: CallContext<JsObject>) -> Result<JsUndefined> {
   let add: i32 = ctx.get::<JsNumber>(0)?.try_into()?;
   let count: i32 = ctx
     .this
@@ -32,3 +34,8 @@ pub fn add_count(mut ctx: CallContext<JsObject>) -> Result<JsUndefined> {
     .set_named_property("count", ctx.env.create_int32(count + add)?)?;
   ctx.env.get_undefined()
 }
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("createTestClass", create_test_class)?;
+  Ok(())
+}
diff --git a/test_module/src/either.rs b/test_module/src/either.rs
index 530bfbd5..195b1ab7 100644
--- a/test_module/src/either.rs
+++ b/test_module/src/either.rs
@@ -1,6 +1,6 @@
 use std::convert::TryInto;
 
-use napi::{CallContext, Either, JsNumber, JsString, Result};
+use napi::{CallContext, Either, JsNumber, JsString, Module, Result};
 
 #[js_function(1)]
 pub fn either_number_string(ctx: CallContext) -> Result<Either<JsNumber, JsString>> {
@@ -27,3 +27,9 @@ pub fn dynamic_argument_length(ctx: CallContext) -> Result<JsNumber> {
     ctx.env.create_uint32(42)
   }
 }
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("eitherNumberString", either_number_string)?;
+  module.create_named_method("dynamicArgumentLength", dynamic_argument_length)?;
+  Ok(())
+}
diff --git a/test_module/src/env.rs b/test_module/src/env.rs
new file mode 100644
index 00000000..33aaf692
--- /dev/null
+++ b/test_module/src/env.rs
@@ -0,0 +1,35 @@
+use napi::{CallContext, JsBoolean, JsUnknown, Module, Result};
+
+#[js_function(2)]
+pub fn instanceof(ctx: CallContext) -> Result<JsBoolean> {
+  let object = ctx.get::<JsUnknown>(0)?;
+  let constructor = ctx.get::<JsUnknown>(1)?;
+  ctx.env.get_boolean(object.instanceof(constructor)?)
+}
+
+#[js_function(1)]
+pub fn is_typedarray(ctx: CallContext) -> Result<JsBoolean> {
+  let js_value = ctx.get::<JsUnknown>(0)?;
+  ctx.env.get_boolean(js_value.is_typedarray()?)
+}
+
+#[js_function(1)]
+pub fn is_dataview(ctx: CallContext) -> Result<JsBoolean> {
+  let js_value = ctx.get::<JsUnknown>(0)?;
+  ctx.env.get_boolean(js_value.is_dataview()?)
+}
+
+#[js_function(2)]
+pub fn strict_equals(ctx: CallContext) -> Result<JsBoolean> {
+  let a: JsUnknown = ctx.get(0)?;
+  let b: JsUnknown = ctx.get(1)?;
+  ctx.env.get_boolean(ctx.env.strict_equals(a, b)?)
+}
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("instanceof", instanceof)?;
+  module.create_named_method("isTypedarray", is_typedarray)?;
+  module.create_named_method("isDataview", is_dataview)?;
+  module.create_named_method("strictEquals", strict_equals)?;
+  Ok(())
+}
diff --git a/test_module/src/error.rs b/test_module/src/error.rs
new file mode 100644
index 00000000..b833eb65
--- /dev/null
+++ b/test_module/src/error.rs
@@ -0,0 +1,33 @@
+use napi::{CallContext, Error, JsBoolean, JsString, JsUnknown, Module, Result, Status};
+
+#[js_function]
+fn test_throw(_ctx: CallContext) -> Result<JsUnknown> {
+  Err(Error::from_status(Status::GenericFailure))
+}
+
+#[js_function(1)]
+fn test_throw_with_reason(ctx: CallContext) -> Result<JsUnknown> {
+  let reason = ctx.get::<JsString>(0)?;
+  Err(Error::new(
+    Status::GenericFailure,
+    reason.as_str()?.to_owned(),
+  ))
+}
+
+#[js_function]
+pub fn test_throw_with_panic(_ctx: CallContext) -> Result<JsUnknown> {
+  panic!("don't panic.");
+}
+
+#[js_function(1)]
+pub fn is_error(ctx: CallContext) -> Result<JsBoolean> {
+  let js_value = ctx.get::<JsUnknown>(0)?;
+  ctx.env.get_boolean(js_value.is_error()?)
+}
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("testThrow", test_throw)?;
+  module.create_named_method("testThrowWithReason", test_throw_with_reason)?;
+  module.create_named_method("isError", is_error)?;
+  Ok(())
+}
diff --git a/test_module/src/external.rs b/test_module/src/external.rs
index b69edfb5..c46a6be4 100644
--- a/test_module/src/external.rs
+++ b/test_module/src/external.rs
@@ -1,6 +1,6 @@
 use std::convert::TryInto;
 
-use napi::{CallContext, JsExternal, JsNumber, Result};
+use napi::{CallContext, JsExternal, JsNumber, Module, Result};
 
 struct NativeObject {
   count: i32,
@@ -19,3 +19,9 @@ pub fn get_external_count(ctx: CallContext) -> Result<JsNumber> {
   let native_object = ctx.env.get_value_external::<NativeObject>(&attached_obj)?;
   ctx.env.create_int32(native_object.count)
 }
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("createExternal", create_external)?;
+  module.create_named_method("getExternalCount", get_external_count)?;
+  Ok(())
+}
diff --git a/test_module/src/function.rs b/test_module/src/function.rs
index ef9a9596..f9e33845 100644
--- a/test_module/src/function.rs
+++ b/test_module/src/function.rs
@@ -1,4 +1,4 @@
-use napi::{CallContext, JsFunction, JsNull, JsObject, Result};
+use napi::{CallContext, JsFunction, JsNull, JsObject, Module, Result};
 
 #[js_function(1)]
 pub fn call_function(ctx: CallContext) -> Result<JsNull> {
@@ -20,3 +20,9 @@ pub fn call_function_with_this(ctx: CallContext<JsObject>) -> Result<JsNull> {
 
   ctx.env.get_null()
 }
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("testCallFunction", call_function)?;
+  module.create_named_method("testCallFunctionWithThis", call_function_with_this)?;
+  Ok(())
+}
diff --git a/test_module/src/lib.rs b/test_module/src/lib.rs
index e8ff8315..5d30ecc5 100644
--- a/test_module/src/lib.rs
+++ b/test_module/src/lib.rs
@@ -5,7 +5,7 @@ extern crate napi_derive;
 #[macro_use]
 extern crate serde_derive;
 
-use napi::{CallContext, Error, JsBoolean, JsString, JsUnknown, Module, Result, Status};
+use napi::{Module, Result};
 
 #[cfg(napi4)]
 mod libuv;
@@ -21,142 +21,44 @@ mod tokio_rt;
 mod buffer;
 mod class;
 mod either;
+mod env;
+mod error;
 mod external;
 mod function;
 mod napi_version;
+mod object;
 mod serde;
 mod string;
 mod symbol;
 mod task;
 
-use buffer::{buffer_to_string, get_buffer_length};
-use either::{dynamic_argument_length, either_number_string};
-use external::{create_external, get_external_count};
-use function::{call_function, call_function_with_this};
-#[cfg(napi4)]
-use libuv::read_file::uv_read_file;
-#[cfg(napi4)]
-use napi4::{test_threadsafe_function, test_tokio_readfile, test_tsfn_error};
-#[cfg(napi5)]
-use napi5::is_date::test_object_is_date;
-#[cfg(napi6)]
-use napi6::bigint::{
-  test_create_bigint_from_i128, test_create_bigint_from_i64, test_create_bigint_from_u128,
-  test_create_bigint_from_u64, test_create_bigint_from_words, test_get_bigint_i64,
-  test_get_bigint_u64, test_get_bigint_words,
-};
 use napi_version::get_napi_version;
-use symbol::{create_named_symbol, create_symbol_from_js_string, create_unnamed_symbol};
-use task::test_spawn_thread;
-#[cfg(napi4)]
-use tokio_rt::{error_from_tokio_future, test_execute_tokio_readfile};
 
 register_module!(test_module, init);
 
 fn init(module: &mut Module) -> Result<()> {
-  serde::register_serde_func(module)?;
-  module.create_named_method("testThrow", test_throw)?;
-  module.create_named_method("testThrowWithReason", test_throw_with_reason)?;
-  module.create_named_method("testSpawnThread", test_spawn_thread)?;
-  module.create_named_method("createExternal", create_external)?;
-  module.create_named_method("getExternalCount", get_external_count)?;
-  module.create_named_method("getBufferLength", get_buffer_length)?;
-  module.create_named_method("bufferToString", buffer_to_string)?;
-  module.create_named_method("createNamedSymbol", create_named_symbol)?;
-  module.create_named_method("createUnnamedSymbol", create_unnamed_symbol)?;
-  module.create_named_method("createSymbolFromJsString", create_symbol_from_js_string)?;
   module.create_named_method("getNapiVersion", get_napi_version)?;
-  module.create_named_method("testCallFunction", call_function)?;
-  module.create_named_method("testCallFunctionWithThis", call_function_with_this)?;
-  module.create_named_method("eitherNumberString", either_number_string)?;
-  module.create_named_method("dynamicArgumentLength", dynamic_argument_length)?;
-  module.create_named_method("createTestClass", class::create_test_class)?;
-  module.create_named_method("concatString", string::concat_string)?;
-  module.create_named_method("instanceof", instanceof)?;
-  module.create_named_method("isError", is_error)?;
-  module.create_named_method("isTypedarray", is_typedarray)?;
-  module.create_named_method("isDataview", is_dataview)?;
-  module.create_named_method("strictEquals", strict_equals)?;
+  error::register_js(module)?;
+  string::register_js(module)?;
+  serde::register_js(module)?;
+  task::register_js(module)?;
+  external::register_js(module)?;
+  buffer::register_js(module)?;
+  either::register_js(module)?;
+  symbol::register_js(module)?;
+  function::register_js(module)?;
+  class::register_js(module)?;
+  env::register_js(module)?;
+  object::register_js(module)?;
   #[cfg(napi4)]
-  module.create_named_method("testExecuteTokioReadfile", test_execute_tokio_readfile)?;
+  napi4::register_js(module)?;
   #[cfg(napi4)]
-  module.create_named_method("testTsfnError", test_tsfn_error)?;
+  tokio_rt::register_js(module)?;
   #[cfg(napi4)]
-  module.create_named_method("testThreadsafeFunction", test_threadsafe_function)?;
-  #[cfg(napi4)]
-  module.create_named_method("testTokioReadfile", test_tokio_readfile)?;
-  #[cfg(napi4)]
-  module.create_named_method("testTokioError", error_from_tokio_future)?;
-  #[cfg(napi4)]
-  module.create_named_method("uvReadFile", uv_read_file)?;
+  libuv::read_file::register_js(module)?;
   #[cfg(napi5)]
-  module.create_named_method("testObjectIsDate", test_object_is_date)?;
+  napi5::register_js(module)?;
   #[cfg(napi6)]
-  module.create_named_method("testCreateBigintFromI64", test_create_bigint_from_i64)?;
-  #[cfg(napi6)]
-  module.create_named_method("testCreateBigintFromU64", test_create_bigint_from_u64)?;
-  #[cfg(napi6)]
-  module.create_named_method("testCreateBigintFromI128", test_create_bigint_from_i128)?;
-  #[cfg(napi6)]
-  module.create_named_method("testCreateBigintFromU128", test_create_bigint_from_u128)?;
-  #[cfg(napi6)]
-  module.create_named_method("testCreateBigintFromWords", test_create_bigint_from_words)?;
-  #[cfg(napi6)]
-  module.create_named_method("testGetBigintI64", test_get_bigint_i64)?;
-  #[cfg(napi6)]
-  module.create_named_method("testGetBigintU64", test_get_bigint_u64)?;
-  #[cfg(napi6)]
-  module.create_named_method("testGetBigintWords", test_get_bigint_words)?;
+  napi6::register_js(module)?;
   Ok(())
 }
-
-#[js_function]
-fn test_throw(_ctx: CallContext) -> Result<JsUnknown> {
-  Err(Error::from_status(Status::GenericFailure))
-}
-
-#[js_function(1)]
-fn test_throw_with_reason(ctx: CallContext) -> Result<JsUnknown> {
-  let reason = ctx.get::<JsString>(0)?;
-  Err(Error::new(
-    Status::GenericFailure,
-    reason.as_str()?.to_owned(),
-  ))
-}
-
-#[js_function]
-pub fn test_throw_with_panic(_ctx: CallContext) -> Result<JsUnknown> {
-  panic!("don't panic.");
-}
-
-#[js_function(2)]
-pub fn instanceof(ctx: CallContext) -> Result<JsBoolean> {
-  let object = ctx.get::<JsUnknown>(0)?;
-  let constructor = ctx.get::<JsUnknown>(1)?;
-  ctx.env.get_boolean(object.instanceof(constructor)?)
-}
-
-#[js_function(1)]
-pub fn is_error(ctx: CallContext) -> Result<JsBoolean> {
-  let js_value = ctx.get::<JsUnknown>(0)?;
-  ctx.env.get_boolean(js_value.is_error()?)
-}
-
-#[js_function(1)]
-pub fn is_typedarray(ctx: CallContext) -> Result<JsBoolean> {
-  let js_value = ctx.get::<JsUnknown>(0)?;
-  ctx.env.get_boolean(js_value.is_typedarray()?)
-}
-
-#[js_function(1)]
-pub fn is_dataview(ctx: CallContext) -> Result<JsBoolean> {
-  let js_value = ctx.get::<JsUnknown>(0)?;
-  ctx.env.get_boolean(js_value.is_dataview()?)
-}
-
-#[js_function(2)]
-pub fn strict_equals(ctx: CallContext) -> Result<JsBoolean> {
-  let a: JsUnknown = ctx.get(0)?;
-  let b: JsUnknown = ctx.get(1)?;
-  ctx.env.get_boolean(ctx.env.strict_equals(a, b)?)
-}
diff --git a/test_module/src/libuv/read_file.rs b/test_module/src/libuv/read_file.rs
index 04258f56..cb4b0e75 100644
--- a/test_module/src/libuv/read_file.rs
+++ b/test_module/src/libuv/read_file.rs
@@ -1,9 +1,9 @@
-use std::thread;
 use std::fs;
+use std::thread;
 
-use futures::prelude::*;
 use futures::channel::oneshot;
-use napi::{CallContext, Result, JsString, JsObject, Status, Error};
+use futures::prelude::*;
+use napi::{CallContext, Error, JsObject, JsString, Module, Result, Status};
 
 #[js_function(1)]
 pub fn uv_read_file(ctx: CallContext) -> Result<JsObject> {
@@ -14,7 +14,15 @@ pub fn uv_read_file(ctx: CallContext) -> Result<JsObject> {
     let res = fs::read(p).map_err(|e| Error::new(Status::Unknown, format!("{}", e)));
     sender.send(res).expect("Send data failed");
   });
-  ctx.env.execute(receiver.map_err(|e| Error::new(Status::Unknown, format!("{}", e))).map(|x| x.and_then(|x| x)), |&mut env, data| {
-    env.create_buffer_with_data(data)
-  })
+  ctx.env.execute(
+    receiver
+      .map_err(|e| Error::new(Status::Unknown, format!("{}", e)))
+      .map(|x| x.and_then(|x| x)),
+    |&mut env, data| env.create_buffer_with_data(data),
+  )
+}
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("uvReadFile", uv_read_file)?;
+  Ok(())
 }
diff --git a/test_module/src/napi4/mod.rs b/test_module/src/napi4/mod.rs
index 832dd8ee..52296cae 100644
--- a/test_module/src/napi4/mod.rs
+++ b/test_module/src/napi4/mod.rs
@@ -1,3 +1,12 @@
+use napi::{Module, Result};
+
 mod tsfn;
 
-pub use tsfn::*;
+use tsfn::*;
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("testTsfnError", test_tsfn_error)?;
+  module.create_named_method("testThreadsafeFunction", test_threadsafe_function)?;
+  module.create_named_method("testTokioReadfile", test_tokio_readfile)?;
+  Ok(())
+}
diff --git a/test_module/src/napi5/is_date.rs b/test_module/src/napi5/date.rs
similarity index 100%
rename from test_module/src/napi5/is_date.rs
rename to test_module/src/napi5/date.rs
diff --git a/test_module/src/napi5/mod.rs b/test_module/src/napi5/mod.rs
index ca06b83a..2554cc82 100644
--- a/test_module/src/napi5/mod.rs
+++ b/test_module/src/napi5/mod.rs
@@ -1 +1,8 @@
-pub mod is_date;
+use napi::{Module, Result};
+
+mod date;
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("testObjectIsDate", date::test_object_is_date)?;
+  Ok(())
+}
diff --git a/test_module/src/napi6/bigint.rs b/test_module/src/napi6/bigint.rs
index c5340227..2bd6eada 100644
--- a/test_module/src/napi6/bigint.rs
+++ b/test_module/src/napi6/bigint.rs
@@ -49,13 +49,7 @@ pub fn test_get_bigint_words(ctx: CallContext) -> Result<JsObject> {
     .create_bigint_from_words(true, vec![i64::max_value() as u64, i64::max_value() as u64])?;
   let mut js_arr = ctx.env.create_array_with_length(2)?;
   let (_signed, words) = js_bigint.get_words()?;
-  js_arr.set_number_indexed_property(
-    ctx.env.create_int64(0)?,
-    ctx.env.create_bigint_from_u64(words[0])?,
-  )?;
-  js_arr.set_number_indexed_property(
-    ctx.env.create_int64(1)?,
-    ctx.env.create_bigint_from_u64(words[1])?,
-  )?;
+  js_arr.set_element(0, ctx.env.create_bigint_from_u64(words[0])?)?;
+  js_arr.set_element(1, ctx.env.create_bigint_from_u64(words[1])?)?;
   Ok(js_arr)
 }
diff --git a/test_module/src/napi6/mod.rs b/test_module/src/napi6/mod.rs
index 8f8d1485..7e4121ff 100644
--- a/test_module/src/napi6/mod.rs
+++ b/test_module/src/napi6/mod.rs
@@ -1 +1,17 @@
-pub mod bigint;
+use napi::{Module, Result};
+
+mod bigint;
+
+use bigint::*;
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("testCreateBigintFromI64", test_create_bigint_from_i64)?;
+  module.create_named_method("testCreateBigintFromU64", test_create_bigint_from_u64)?;
+  module.create_named_method("testCreateBigintFromI128", test_create_bigint_from_i128)?;
+  module.create_named_method("testCreateBigintFromU128", test_create_bigint_from_u128)?;
+  module.create_named_method("testCreateBigintFromWords", test_create_bigint_from_words)?;
+  module.create_named_method("testGetBigintI64", test_get_bigint_i64)?;
+  module.create_named_method("testGetBigintU64", test_get_bigint_u64)?;
+  module.create_named_method("testGetBigintWords", test_get_bigint_words)?;
+  Ok(())
+}
diff --git a/test_module/src/object.rs b/test_module/src/object.rs
new file mode 100644
index 00000000..638406ba
--- /dev/null
+++ b/test_module/src/object.rs
@@ -0,0 +1,38 @@
+use napi::{CallContext, JsBoolean, JsObject, JsString, JsUndefined, JsUnknown, Module, Result};
+
+#[js_function(2)]
+fn test_set_property(ctx: CallContext) -> Result<JsUndefined> {
+  let mut obj = ctx.get::<JsObject>(0)?;
+  let key = ctx.get::<JsString>(1)?;
+  obj.set_property(key, ctx.env.create_string("Rust object property")?)?;
+  ctx.env.get_undefined()
+}
+
+#[js_function(2)]
+fn test_set_named_property(ctx: CallContext) -> Result<JsUndefined> {
+  let mut obj = ctx.get::<JsObject>(0)?;
+  let property = ctx.get::<JsUnknown>(1)?;
+  obj.set_named_property("RustPropertyKey", property)?;
+  ctx.env.get_undefined()
+}
+
+#[js_function(1)]
+fn test_get_named_property(ctx: CallContext) -> Result<JsUnknown> {
+  let obj = ctx.get::<JsObject>(0)?;
+  obj.get_named_property("p")
+}
+
+#[js_function(2)]
+fn test_has_named_property(ctx: CallContext) -> Result<JsBoolean> {
+  let obj = ctx.get::<JsObject>(0)?;
+  let key = ctx.get::<JsString>(1)?;
+  ctx.env.get_boolean(obj.has_named_property(key.as_str()?)?)
+}
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("testSetProperty", test_set_property)?;
+  module.create_named_method("testSetNamedProperty", test_set_named_property)?;
+  module.create_named_method("testGetNamedProperty", test_get_named_property)?;
+  module.create_named_method("testHasNamedProperty", test_has_named_property)?;
+  Ok(())
+}
diff --git a/test_module/src/serde.rs b/test_module/src/serde.rs
index ebc2ce14..6c99c87f 100644
--- a/test_module/src/serde.rs
+++ b/test_module/src/serde.rs
@@ -162,7 +162,7 @@ fn roundtrip_object(ctx: CallContext) -> Result<JsUnknown> {
   ctx.env.to_js_value(&de_serialized)
 }
 
-pub fn register_serde_func(m: &mut Module) -> Result<()> {
+pub fn register_js(m: &mut Module) -> Result<()> {
   m.create_named_method("make_num_77", make_num_77)?;
   m.create_named_method("make_num_32", make_num_32)?;
   m.create_named_method("make_str_hello", make_str_hello)?;
diff --git a/test_module/src/string.rs b/test_module/src/string.rs
index 8728146e..125f5c3f 100644
--- a/test_module/src/string.rs
+++ b/test_module/src/string.rs
@@ -1,4 +1,4 @@
-use napi::{CallContext, JsString, Result};
+use napi::{CallContext, JsString, Module, Result};
 
 #[js_function(1)]
 pub fn concat_string(ctx: CallContext) -> Result<JsString> {
@@ -6,3 +6,8 @@ pub fn concat_string(ctx: CallContext) -> Result<JsString> {
   let out_string = format!("{} + Rust 🦀 string!", in_string.as_str()?);
   ctx.env.create_string_from_std(out_string)
 }
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("concatString", concat_string)?;
+  Ok(())
+}
diff --git a/test_module/src/symbol.rs b/test_module/src/symbol.rs
index ef912ac1..e4770b29 100644
--- a/test_module/src/symbol.rs
+++ b/test_module/src/symbol.rs
@@ -1,4 +1,4 @@
-use napi::{CallContext, JsString, JsSymbol, Result};
+use napi::{CallContext, JsString, JsSymbol, Module, Result};
 
 #[js_function]
 pub fn create_named_symbol(ctx: CallContext) -> Result<JsSymbol> {
@@ -15,3 +15,10 @@ pub fn create_symbol_from_js_string(ctx: CallContext) -> Result<JsSymbol> {
   let name = ctx.get::<JsString>(0)?;
   ctx.env.create_symbol_from_js_string(name)
 }
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("createNamedSymbol", create_named_symbol)?;
+  module.create_named_method("createUnnamedSymbol", create_unnamed_symbol)?;
+  module.create_named_method("createSymbolFromJsString", create_symbol_from_js_string)?;
+  Ok(())
+}
diff --git a/test_module/src/task.rs b/test_module/src/task.rs
index d570f545..c2ad5f66 100644
--- a/test_module/src/task.rs
+++ b/test_module/src/task.rs
@@ -1,6 +1,6 @@
 use std::convert::TryInto;
 
-use napi::{CallContext, Env, JsNumber, JsObject, Result, Task};
+use napi::{CallContext, Env, JsNumber, JsObject, Module, Result, Task};
 
 struct ComputeFib {
   n: u32,
@@ -34,8 +34,13 @@ fn fibonacci_native(n: u32) -> u32 {
 }
 
 #[js_function(1)]
-pub fn test_spawn_thread(ctx: CallContext) -> Result<JsObject> {
+fn test_spawn_thread(ctx: CallContext) -> Result<JsObject> {
   let n = ctx.get::<JsNumber>(0)?;
   let task = ComputeFib::new(n.try_into()?);
   ctx.env.spawn(task)
 }
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("testSpawnThread", test_spawn_thread)?;
+  Ok(())
+}
diff --git a/test_module/src/tokio_rt/mod.rs b/test_module/src/tokio_rt/mod.rs
index 5e6f6d4f..7d34e233 100644
--- a/test_module/src/tokio_rt/mod.rs
+++ b/test_module/src/tokio_rt/mod.rs
@@ -1,3 +1,11 @@
+use napi::{Module, Result};
+
 mod read_file;
 
-pub use read_file::*;
+use read_file::*;
+
+pub fn register_js(module: &mut Module) -> Result<()> {
+  module.create_named_method("testExecuteTokioReadfile", test_execute_tokio_readfile)?;
+  module.create_named_method("testTokioError", error_from_tokio_future)?;
+  Ok(())
+}