diff --git a/apps/keyboard/test/unit/imes/latin/worker_test.js b/apps/keyboard/test/unit/imes/latin/worker_test.js
index 4b3309a0e9da..f10953c3f6ec 100644
--- a/apps/keyboard/test/unit/imes/latin/worker_test.js
+++ b/apps/keyboard/test/unit/imes/latin/worker_test.js
@@ -1,9 +1,6 @@
 /*global InputMethodDatabaseLoader, WordListConverter, InputMethods, dump */
 'use strict';
 
-require('/test/unit/setup_engine.js');
-require('/js/imes/latin/latin.js');
-
 require('/js/settings/word_list_converter.js');
 require('/js/keyboard/input_method_database_loader.js');
 
@@ -11,439 +8,439 @@ suite('Latin worker', function() {
   var worker;
   var keymaps = {};
 
-  suiteSetup(function() {
-    worker = new Worker('../../../../js/imes/latin/worker.js');
-
-    keymaps.qwerty = InputMethods.latin.generateNearbyKeyMap({
-      'keyboardWidth': 320,
-      'keyboardHeight': 205,
-      'keyArray': [{
-        'code': 113,
-        'x': 0,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 119,
-        'x': 32,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 101,
-        'x': 64,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 114,
-        'x': 96,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 116,
-        'x': 128,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 121,
-        'x': 160,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 117,
-        'x': 192,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 105,
-        'x': 224,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 111,
-        'x': 256,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 112,
-        'x': 288,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 97,
-        'x': 16,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 115,
-        'x': 48,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 100,
-        'x': 80,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 102,
-        'x': 112,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 103,
-        'x': 144,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 104,
-        'x': 176,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 106,
-        'x': 208,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 107,
-        'x': 240,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 108,
-        'x': 272,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 20,
-        'x': 0,
-        'y': 131,
-        'width': 48,
-        'height': 43
-      }, {
-        'code': 122,
-        'x': 48,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 120,
-        'x': 80,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 99,
-        'x': 112,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 118,
-        'x': 144,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 98,
-        'x': 176,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 110,
-        'x': 208,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 109,
-        'x': 240,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 8,
-        'x': 272,
-        'y': 131,
-        'width': 48,
-        'height': 43
-      }, {
-        'code': 65534,
-        'x': 0,
-        'y': 182,
-        'width': 48,
-        'height': 43
-      }, {
-        'code': 65533,
-        'x': 48,
-        'y': 182,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 32,
-        'x': 80,
-        'y': 182,
-        'width': 144,
-        'height': 43
-      }, {
-        'code': 46,
-        'x': 224,
-        'y': 182,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 13,
-        'x': 256,
-        'y': 182,
-        'width': 64,
-        'height': 43
-      }],
-      'keyWidth': 32,
-      'keyHeight': 50
-    });
-
-    keymaps.azerty = InputMethods.latin.generateNearbyKeyMap({
-      'keyboardWidth': 320,
-      'keyboardHeight': 205,
-      'keyArray': [{
-        'code': 97,
-        'x': 0,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 122,
-        'x': 32,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 101,
-        'x': 64,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 114,
-        'x': 96,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 116,
-        'x': 128,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 121,
-        'x': 160,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 117,
-        'x': 192,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 105,
-        'x': 224,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 111,
-        'x': 256,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 112,
-        'x': 288,
-        'y': 29,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 113,
-        'x': 0,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 115,
-        'x': 32,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 100,
-        'x': 64,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 102,
-        'x': 96,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 103,
-        'x': 128,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 104,
-        'x': 160,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 106,
-        'x': 192,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 107,
-        'x': 224,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 108,
-        'x': 256,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 109,
-        'x': 288,
-        'y': 80,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 20,
-        'x': 0,
-        'y': 131,
-        'width': 48,
-        'height': 43
-      }, {
-        'code': 119,
-        'x': 48,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 120,
-        'x': 80,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 99,
-        'x': 112,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 118,
-        'x': 144,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 98,
-        'x': 176,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 110,
-        'x': 208,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 39,
-        'x': 240,
-        'y': 131,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 8,
-        'x': 272,
-        'y': 131,
-        'width': 48,
-        'height': 43
-      }, {
-        'code': 18,
-        'x': 0,
-        'y': 182,
-        'width': 64,
-        'height': 43
-      }, {
-        'code': -3,
-        'x': 64,
-        'y': 182,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 32,
-        'x': 96,
-        'y': 182,
-        'width': 128,
-        'height': 43
-      }, {
-        'code': 46,
-        'x': 224,
-        'y': 182,
-        'width': 32,
-        'height': 43
-      }, {
-        'code': 13,
-        'x': 256,
-        'y': 182,
-        'width': 64,
-        'height': 43
-      }],
-      'keyWidth': 32,
-      'keyHeight': 51
+  suiteSetup(function(done) {
+    window.InputMethods = {};
+    require('/js/imes/latin/latin.js', function() {
+      keymaps.qwerty = InputMethods.latin.generateNearbyKeyMap({
+        'keyboardWidth': 320,
+        'keyboardHeight': 205,
+        'keyArray': [{
+          'code': 113,
+          'x': 0,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 119,
+          'x': 32,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 101,
+          'x': 64,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 114,
+          'x': 96,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 116,
+          'x': 128,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 121,
+          'x': 160,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 117,
+          'x': 192,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 105,
+          'x': 224,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 111,
+          'x': 256,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 112,
+          'x': 288,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 97,
+          'x': 16,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 115,
+          'x': 48,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 100,
+          'x': 80,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 102,
+          'x': 112,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 103,
+          'x': 144,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 104,
+          'x': 176,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 106,
+          'x': 208,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 107,
+          'x': 240,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 108,
+          'x': 272,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 20,
+          'x': 0,
+          'y': 131,
+          'width': 48,
+          'height': 43
+        }, {
+          'code': 122,
+          'x': 48,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 120,
+          'x': 80,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 99,
+          'x': 112,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 118,
+          'x': 144,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 98,
+          'x': 176,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 110,
+          'x': 208,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 109,
+          'x': 240,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 8,
+          'x': 272,
+          'y': 131,
+          'width': 48,
+          'height': 43
+        }, {
+          'code': 65534,
+          'x': 0,
+          'y': 182,
+          'width': 48,
+          'height': 43
+        }, {
+          'code': 65533,
+          'x': 48,
+          'y': 182,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 32,
+          'x': 80,
+          'y': 182,
+          'width': 144,
+          'height': 43
+        }, {
+          'code': 46,
+          'x': 224,
+          'y': 182,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 13,
+          'x': 256,
+          'y': 182,
+          'width': 64,
+          'height': 43
+        }],
+        'keyWidth': 32,
+        'keyHeight': 50
+      });
+
+      keymaps.azerty = InputMethods.latin.generateNearbyKeyMap({
+        'keyboardWidth': 320,
+        'keyboardHeight': 205,
+        'keyArray': [{
+          'code': 97,
+          'x': 0,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 122,
+          'x': 32,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 101,
+          'x': 64,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 114,
+          'x': 96,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 116,
+          'x': 128,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 121,
+          'x': 160,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 117,
+          'x': 192,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 105,
+          'x': 224,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 111,
+          'x': 256,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 112,
+          'x': 288,
+          'y': 29,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 113,
+          'x': 0,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 115,
+          'x': 32,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 100,
+          'x': 64,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 102,
+          'x': 96,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 103,
+          'x': 128,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 104,
+          'x': 160,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 106,
+          'x': 192,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 107,
+          'x': 224,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 108,
+          'x': 256,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 109,
+          'x': 288,
+          'y': 80,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 20,
+          'x': 0,
+          'y': 131,
+          'width': 48,
+          'height': 43
+        }, {
+          'code': 119,
+          'x': 48,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 120,
+          'x': 80,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 99,
+          'x': 112,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 118,
+          'x': 144,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 98,
+          'x': 176,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 110,
+          'x': 208,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 39,
+          'x': 240,
+          'y': 131,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 8,
+          'x': 272,
+          'y': 131,
+          'width': 48,
+          'height': 43
+        }, {
+          'code': 18,
+          'x': 0,
+          'y': 182,
+          'width': 64,
+          'height': 43
+        }, {
+          'code': -3,
+          'x': 64,
+          'y': 182,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 32,
+          'x': 96,
+          'y': 182,
+          'width': 128,
+          'height': 43
+        }, {
+          'code': 46,
+          'x': 224,
+          'y': 182,
+          'width': 32,
+          'height': 43
+        }, {
+          'code': 13,
+          'x': 256,
+          'y': 182,
+          'width': 64,
+          'height': 43
+        }],
+        'keyWidth': 32,
+        'keyHeight': 51
+      });
+
+      done();
     });
   });
 
   setup(function() {
-    worker.onmessage = sinon.stub();
+    worker = new Worker('../../../../js/imes/latin/worker.js');
   });
 
-  test('Worker should throw if language doesnt exist', function(next) {
-    worker.postMessage({ cmd: 'setLanguage', args: ['no-existente'] });
-    onWorkerMessage(function(data) {
-
-      assert.equal(data.cmd, 'error');
-      next();
-    });
+  teardown(function() {
+    worker.terminate();
+    worker.onmessage = null;
+    worker = null;
   });
 
   function onWorkerMessage(filter, callback) {
@@ -451,22 +448,13 @@ suite('Latin worker', function() {
       callback = filter;
       filter = undefined;
     }
-    var occ = worker.onmessage.callCount;
-    var iv = setInterval(function() {
-      if (worker.onmessage.callCount > occ) {
-        var ev = worker.onmessage.args[worker.onmessage.callCount - 1][0];
-        // console.log(ev.data);
-
-        occ = worker.onmessage.callCount;
-
-        if (filter !== undefined && ev.data.cmd !== filter) {
-          return;
-        }
-
-        clearInterval(iv);
-        callback(ev.data);
+    worker.onmessage = function handleWorkerMessage(evt) {
+      if (filter !== undefined && evt.data.cmd !== filter) {
+        return;
       }
-    }, 20);
+
+      callback(evt.data);
+    };
   }
 
   function prediction(input, expected, next) {
@@ -517,7 +505,7 @@ suite('Latin worker', function() {
     var successCount = 0;
     worker.onmessage = function(e) {
       if (e.data.cmd !== 'success') {
-        dump('worker.onmessage unexpected result ' + e.message + '\n');
+        dump('worker.onmessage unexpected result ' + e.data.message + '\n');
       }
 
       assert.equal(e.data.cmd, 'success');
@@ -527,14 +515,23 @@ suite('Latin worker', function() {
         successCount++;
 
         if (successCount === 4) {
+          worker.onmessage = null;
           next();
         }
       }
     };
   }
 
+  test('Worker should throw if no dictData is passed', function(done) {
+    worker.postMessage({ cmd: 'setLanguage', args: ['en_us', null] });
+    onWorkerMessage('error', function(data) {
+      assert.equal(data.cmd, 'error');
+      done();
+    });
+  });
+
   suite('en_us predictions', function() {
-    suiteSetup(function(next) {
+    setup(function(next) {
       setupLanguage('en_us', keymaps.qwerty, undefined, next);
     });
 
@@ -626,8 +623,8 @@ suite('Latin worker', function() {
       test('Should not suggest word in offensive list #1', function(next) {
         worker.postMessage({ cmd: 'predict', args: ['fuc'] });
 
-        onWorkerMessage(function() {
-          var suggestions = worker.onmessage.args[0][0].data.suggestions;
+        onWorkerMessage(function(data) {
+          var suggestions = data.suggestions;
 
           assert.notEqual(suggestions[0][0], 'fuck');
           assert.notEqual(suggestions[1][0], 'fuck');
@@ -640,8 +637,8 @@ suite('Latin worker', function() {
       test('Should not suggest word in offensive list #2', function(next) {
         worker.postMessage({ cmd: 'predict', args: ['peni'] });
 
-        onWorkerMessage(function() {
-          var suggestions = worker.onmessage.args[0][0].data.suggestions;
+        onWorkerMessage(function(data) {
+          var suggestions = data.suggestions;
 
           assert.notEqual(suggestions[0][0], 'penis');
           assert.notEqual(suggestions[1][0], 'penis');
@@ -718,14 +715,14 @@ suite('Latin worker', function() {
   // alternately.
   suite('predictions in conjuction with user dictionary', function() {
     var blob;
-    suiteSetup(function() {
+    setup(function() {
       blob = new WordListConverter(
         ['Mozilla', 'MozSpace', 'MozTrap', 'mozSettings', 'Mozillian'])
         .toBlob();
     });
 
     suite('with user dictionary blob at setupLanguage', function() {
-      suiteSetup(function(next) {
+      setup(function(next) {
         setupLanguage('en_gb', keymaps.qwerty, blob, next);
       });
 
@@ -741,7 +738,7 @@ suite('Latin worker', function() {
     });
 
     suite('with user dictionary blob supplied later', function() {
-      suiteSetup(function(next) {
+      setup(function(next) {
         setupLanguage('en_us', keymaps.qwerty, undefined, function() {
           worker.addEventListener('message', function onMessage(e) {
             if ('success' === e.data.cmd && 'setUserDictionary' === e.data.fn) {
@@ -769,7 +766,7 @@ suite('Latin worker', function() {
 
 
     suite('with user dictionary blob nullified later', function() {
-      suiteSetup(function(next) {
+      setup(function(next) {
         setupLanguage('en_gb', keymaps.qwerty, blob, function() {
           worker.addEventListener('message', function onMessage(e) {
             if ('success' === e.data.cmd && 'setUserDictionary' === e.data.fn) {
@@ -797,7 +794,7 @@ suite('Latin worker', function() {
   });
 
   suite('fr predictions', function() {
-    suiteSetup(function(next) {
+    setup(function(next) {
       setupLanguage('fr', keymaps.azerty, undefined, next);
     });
 
@@ -807,7 +804,7 @@ suite('Latin worker', function() {
   });
 
   suite('validChars() is tolerant on small dicts', function() {
-    suiteSetup(function(next) {
+    setup(function(next) {
       var dictData = new WordListConverter(['Ápple']).toBlob();
 
       worker.postMessage({