diff --git a/lib/mongodb.js b/lib/mongodb.js
index 61c9efe92..165d63582 100644
--- a/lib/mongodb.js
+++ b/lib/mongodb.js
@@ -2033,7 +2033,7 @@ function visitAllProperties(data, modelCtorOrDef, visitor) {
  * Decimal128 type
  */
 function coerceDecimalProperty(propValue, propDef, setValue) {
-  var updatedValue;
+  let updatedValue;
   if (hasDataType('decimal128', propDef)) {
     if (Array.isArray(propValue)) {
       updatedValue = propValue.map(val => Decimal128.fromString(val));
diff --git a/test/decimal.test.js b/test/decimal.test.js
index 586be7c25..7a8825fe9 100644
--- a/test/decimal.test.js
+++ b/test/decimal.test.js
@@ -9,12 +9,7 @@ require('./init.js');
 const promisify = require('bluebird').promisify;
 const Decimal128 = require('mongodb').Decimal128;
 
-var db,
-  OrderDecimal,
-  modelWithDecimalArray,
-  modelWithDecimalNestedArray,
-  modelWithDecimalNestedObject,
-  modelWithDeepNestedDecimalProps;
+var db, OrderDecimal;
 
 describe('model with decimal property', function() {
   before(function(done) {
@@ -70,7 +65,7 @@ describe('model with decimal property', function() {
 
   context('nested decimal props', function() {
     it('should create/update instance for array of decimal props', function() {
-      modelWithDecimalArray = db.define('modelWithDecimalArray', {
+      const modelWithDecimalArray = db.define('modelWithDecimalArray', {
         randomReview: {
           type: [String],
           mongodb: {
@@ -116,7 +111,7 @@ describe('model with decimal property', function() {
         });
     });
     it('should create/update instance for nested decimal prop inside array', function() {
-      modelWithDecimalNestedArray = db.define('modelWithDecimalNestedArray', {
+      const modelWithDecimalNestedArray = db.define('modelWithDecimalNestedArray', {
         tickets: {
           type: [
             {
@@ -167,7 +162,7 @@ describe('model with decimal property', function() {
       };
       let instanceId;
 
-      modelWithDecimalNestedArray.create(createData)
+      return modelWithDecimalNestedArray.create(createData)
         .then(function(inst) {
           instanceId = inst.id;
           return findRawModelDataAsync('modelWithDecimalNestedArray', instanceId);
@@ -187,7 +182,7 @@ describe('model with decimal property', function() {
     });
 
     it('should create/update instance for nested decimal prop inside object', function() {
-      modelWithDecimalNestedObject = db.define('modelWithDecimalNestedObject', {
+      const modelWithDecimalNestedObject = db.define('modelWithDecimalNestedObject', {
         awards: {
           type: {
             wins: {
@@ -242,7 +237,7 @@ describe('model with decimal property', function() {
         });
     });
     it('should create/update instance for deeply nested decimal props', function() {
-      modelWithDeepNestedDecimalProps = db.define('modelWithDeepNestedDecimalProps', {
+      const modelWithDeepNestedDecimalProps = db.define('modelWithDeepNestedDecimalProps', {
         imdb: {
           type: {
             duration: {