Avoid adding module import when not needed.

Author: Robert Jackson

__testfixtures__/ember-qunit-codemod/non-module-ember-qunit-imports.input.js

@@ -0,0 +1,8 @@
+import resolver from './helpers/resolver';
+import {
+  setResolver
+} from 'ember-qunit';
+import { start } from 'ember-cli-qunit';
+
+setResolver(resolver);
+start();

__testfixtures__/ember-qunit-codemod/non-module-ember-qunit-imports.output.js

@@ -0,0 +1,8 @@
+import resolver from './helpers/resolver';
+import {
+  setResolver
+} from 'ember-qunit';
+import { start } from 'ember-cli-qunit';
+
+setResolver(resolver);
+start();

ember-qunit-codemod.js

@@ -45,7 +45,7 @@ module.exports = function(file, api, options) {
     // Find `module` and `test` imports
     let migrateToQUnitImport = ['module', 'test', 'skip', 'todo'];
 
-    let specifiers = new Set(['module']);
+    let specifiers = new Set();
     // Replace old with new test helpers imports
     emberQUnitImports
       .find(j.ImportSpecifier)
@@ -84,6 +84,15 @@ module.exports = function(file, api, options) {
         let importName = p.node.imported.name;
         let mappedName = mapping[importName] || importName;
 
+        if (mappedName !== importName) {
+          ensureImportWithSpecifiers({
+            source: 'qunit',
+            anchor: 'ember-qunit',
+            positionMethod: 'insertBefore',
+            specifiers: ['module'],
+          });
+        }
+
         // If importName is `moduleForComponent` determine if we need
         // `setupTest` (unit) or `setupRenderingTest` (integration)
         if (importName === 'moduleForComponent') {