running an IE test in appveyor

appveyor.yml

@@ -19,7 +19,7 @@ test_script:
   - node --version
   - node_modules\.bin\npm --version
   # run tests
-  - node_modules\.bin\npm test
+  - node_modules\.bin\npm run test-ie
 
 # Don't actually build.
 build: off

karma.conf.ie.js

@@ -0,0 +1,13 @@
+module.exports = function (config) {
+  require('./karma.conf.js')(config);
+  config.set({
+    plugins: config.plugins.concat('karma-ie-launcher'),
+    browsers: ['IE'],
+    customLaunchers: {
+      IE11: {
+        base: 'IE',
+        'x-ua-compatible': 'IE=EmulateIE9'
+      }
+    }
+  });
+};