Remove onKeyUp

Author: AsaAyers

lib/assertions.js

@@ -77,11 +77,10 @@ exports.props = {
       }
     },
 
-    // I don't know that it matters if you use onKeyUp or onKeyDown.
     BUTTON_ROLE_ENTER: {
-      msg: 'You have `role="button"` but did not define an `onKeyDown` or `onKeyUp` handler. Add it, and have the "Enter" key do the same thing as an `onClick` handler.',
+      msg: 'You have `role="button"` but did not define an `onKeyDown` handler. Add it, and have the "Enter" key do the same thing as an `onClick` handler.',
       test (tagName, props, children) {
-        return !(props.role === 'button' && !(props.onKeyUp || props.onKeyDown));
+        return !(props.role === 'button' && props.onKeyDown);
       }
     }