HTML Reporter: Move internal diff.js import to core.js

Ref #1118.

src/core.js

@@ -19,6 +19,7 @@ import ProcessingQueue from './core/processing-queue';
 import { on, emit } from './events';
 import onWindowError from './core/onerror';
 import onUncaughtException from './core/on-uncaught-exception';
+import diff from './core/diff';
 
 const QUnit = {};
 
@@ -42,6 +43,7 @@ QUnit.version = '@VERSION';
 extend(QUnit, {
   config,
 
+  diff,
   dump,
   equiv,
   reporters,

src/html-reporter/diff.js → src/core/diff.js

@@ -1,4 +1,4 @@
-import QUnit from '../core';
+/* eslint-disable indent */
 import { escapeText } from '../core/utilities';
 
 /*
@@ -29,7 +29,6 @@ import { escapeText } from '../core/utilities';
  * Usage: QUnit.diff(expected, actual)
  *
  */
-QUnit.diff = (function () {
   function DiffMatchPatch () {
   }
 
@@ -1112,13 +1111,12 @@ QUnit.diff = (function () {
     }
   };
 
-  return function (o, n) {
+  export default function diff (o, n) {
     let diff, output, text;
     diff = new DiffMatchPatch();
     output = diff.DiffMain(o, n);
     diff.diffCleanupEfficiency(output);
     text = diff.diffPrettyHtml(output);
 
     return text;
-  };
-}());
+  }

src/html-reporter/reporter.js

@@ -1,4 +1 @@
-import './fixture';
-import './diff';
-import './urlparams';
 import './html';

src/qunit.js

@@ -1,2 +1,4 @@
 import './core';
-import './html-reporter/reporter';
+import './html-runner/fixture';
+import './html-runner/urlparams';
+import './html-reporter/html';