diff --git a/.travis.yml b/.travis.yml
index ddba366d..214b6493 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,7 @@ cache:
 notifications:
   email: false
 node_js:
-  - '7'
+  - '6'
 before_script:
   - npm prune && npm cache clean
 script:
diff --git a/test/index.test.ts b/test/index.test.ts
index a31f7c27..5b987493 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -1,18 +1,15 @@
 import { Action, KeyCombo, shortcutJS } from '../src'
 import { getMockedEvent } from './utils'
 
+
 /**
  * Mock window
  */
-interface MockWindow extends Window {
-  addEventListener: jest.Mock<{}> & typeof window.addEventListener
-  removeEventListener: jest.Mock<{}> & typeof window.removeEventListener
-}
 function getMockWindow() {
   let myGlobal = global as any
   myGlobal.addEventListener = jest.fn()
   myGlobal.removeEventListener = jest.fn()
-  return myGlobal
+  return myGlobal as any
 }
 
 /**