diff --git a/lib/build.js b/lib/build.js
index 3375a4f4..2898a991 100644
--- a/lib/build.js
+++ b/lib/build.js
@@ -4,6 +4,8 @@ var conf = require('./config');
 var webpack = require('webpack');
 var merge = require('webpack-merge');
 
+const testFilePattern = "\\.(test|spec)\\.?";
+
 // custom babel target for each node version
 function getBabelTarget(envConfig) {
   var key = 'AWS_LAMBDA_JS_RUNTIME';
@@ -75,7 +77,9 @@ function webpackConfig(dir, additionalConfig) {
       rules: [
         {
           test: /\.(m?js|ts)?$/,
-          exclude: /(node_modules|bower_components)/,
+          exclude: new RegExp(
+            `(node_modules|bower_components|${testFilePattern})`
+          ),
           use: {
             loader: 'babel-loader',
             options: babelOpts
@@ -99,8 +103,10 @@ function webpackConfig(dir, additionalConfig) {
   };
   fs.readdirSync(dirPath).forEach(function(file) {
     if (file.match(/\.(m?js|ts)$/)) {
-      var name = file.replace(/\.(m?js|ts)$/, '');
-      webpackConfig.entry[name] = './' + file;
+      var name = file.replace(/\.(m?js|ts)$/, "");
+      if (!name.match(new RegExp(testFilePattern))) {
+        webpackConfig.entry[name] = "./" + file;
+      }
     }
   });
   if (Object.keys(webpackConfig.entry) < 1) {