diff --git a/karma.conf.js b/karma.conf.js
index 30ac506e5..a4e83f693 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -32,7 +32,7 @@ function getPlugins() {
     plugins.push(new IgnorePlugin(/create-react-class/));
   }
 
-  return plugins
+  return plugins;
 }
 
 module.exports = function karma(config) {
@@ -59,7 +59,11 @@ module.exports = function karma(config) {
     reporters: ['dots'],
 
     files: [
-      'test/*-spec.{jsx,js}',
+      'test/*.{jsx,js}',
+    ],
+
+    exclude: [
+      'test/_*.{jsx,js}',
     ],
 
     browsers: [
diff --git a/src/version.js b/src/version.js
index 3a691d7ce..d55f7f3df 100644
--- a/src/version.js
+++ b/src/version.js
@@ -7,4 +7,4 @@ const [major, minor] = VERSION.split('.');
 export const REACT013 = VERSION.slice(0, 4) === '0.13';
 export const REACT014 = VERSION.slice(0, 4) === '0.14';
 export const REACT15 = major === '15';
-export const REACT155 = REACT15 && +minor >= 5;
+export const REACT155 = REACT15 && minor >= 5;