Move UI reducer tests to Jest (#2070)

* Add jest-immutable-matchers

* Move UI reducer tests to Jest

Author: outoftime

jest-setup.js

@@ -1,3 +1,8 @@
+// eslint-disable-next-line import/no-namespace
+import * as immutableMatchers from 'jest-immutable-matchers';
+
+jest.addMatchers(immutableMatchers);
+
 function createRange() {
   // createRange is always called with a Document context
   /* eslint-disable no-invalid-this, consistent-this */

package.json

@@ -357,6 +357,7 @@
     "is-docker": "2.0.0",
     "jest": "24.9.0",
     "jest-extended": "0.11.2",
+    "jest-immutable-matchers": "2.0.1",
     "jscodeshift": "0.7.0",
     "json-loader": "0.5.7",
     "karma": "4.4.1",