diff --git a/tests/mocha/utils_test.js b/tests/mocha/utils_test.js
index 05fce6f3a..3f508f9c6 100644
--- a/tests/mocha/utils_test.js
+++ b/tests/mocha/utils_test.js
@@ -9,78 +9,83 @@ suite('Utils', function() {
       uuids[uuid] = true;
     }
   });
-  test('addClass', function() {
-    var p = document.createElement('p');
-    Blockly.utils.addClass(p, 'one');
-    assertEquals('Adding "one"', 'one', p.className);
-    Blockly.utils.addClass(p, 'one');
-    assertEquals('Adding duplicate "one"', 'one', p.className);
-    Blockly.utils.addClass(p, 'two');
-    assertEquals('Adding "two"', 'one two', p.className);
-    Blockly.utils.addClass(p, 'two');
-    assertEquals('Adding duplicate "two"', 'one two', p.className);
-    Blockly.utils.addClass(p, 'three');
-    assertEquals('Adding "three"', 'one two three', p.className);
+
+  suite('DOM', function() {
+    test('addClass', function() {
+      var p = document.createElement('p');
+      Blockly.utils.dom.addClass(p, 'one');
+      assertEquals('Adding "one"', 'one', p.className);
+      Blockly.utils.dom.addClass(p, 'one');
+      assertEquals('Adding duplicate "one"', 'one', p.className);
+      Blockly.utils.dom.addClass(p, 'two');
+      assertEquals('Adding "two"', 'one two', p.className);
+      Blockly.utils.dom.addClass(p, 'two');
+      assertEquals('Adding duplicate "two"', 'one two', p.className);
+      Blockly.utils.dom.addClass(p, 'three');
+      assertEquals('Adding "three"', 'one two three', p.className);
+    });
+
+    test('hasClass', function() {
+      var p = document.createElement('p');
+      p.className = ' one three  two three  ';
+      assertTrue('Has "one"', Blockly.utils.dom.hasClass(p, 'one'));
+      assertTrue('Has "two"', Blockly.utils.dom.hasClass(p, 'two'));
+      assertTrue('Has "three"', Blockly.utils.dom.hasClass(p, 'three'));
+      assertFalse('Has no "four"', Blockly.utils.dom.hasClass(p, 'four'));
+      assertFalse('Has no "t"', Blockly.utils.dom.hasClass(p, 't'));
+    });
+
+    test('removeClass', function() {
+      var p = document.createElement('p');
+      p.className = ' one three  two three  ';
+      Blockly.utils.dom.removeClass(p, 'two');
+      assertEquals('Removing "two"', 'one three three', p.className);
+      Blockly.utils.dom.removeClass(p, 'four');
+      assertEquals('Removing "four"', 'one three three', p.className);
+      Blockly.utils.dom.removeClass(p, 'three');
+      assertEquals('Removing "three"', 'one', p.className);
+      Blockly.utils.dom.removeClass(p, 'ne');
+      assertEquals('Removing "ne"', 'one', p.className);
+      Blockly.utils.dom.removeClass(p, 'one');
+      assertEquals('Removing "one"', '', p.className);
+      Blockly.utils.dom.removeClass(p, 'zero');
+      assertEquals('Removing "zero"', '', p.className);
+    });
   });
 
-  test('hasClass', function() {
-    var p = document.createElement('p');
-    p.className = ' one three  two three  ';
-    assertTrue('Has "one"', Blockly.utils.hasClass(p, 'one'));
-    assertTrue('Has "two"', Blockly.utils.hasClass(p, 'two'));
-    assertTrue('Has "three"', Blockly.utils.hasClass(p, 'three'));
-    assertFalse('Has no "four"', Blockly.utils.hasClass(p, 'four'));
-    assertFalse('Has no "t"', Blockly.utils.hasClass(p, 't'));
-  });
+  suite('String', function() {
+    test('shortest string length', function() {
+      var len = Blockly.utils.string.shortestStringLength('one,two,three,four,five'.split(','));
+      assertEquals('Length of "one"', 3, len);
+      len = Blockly.utils.string.shortestStringLength('one,two,three,four,five,'.split(','));
+      assertEquals('Length of ""', 0, len);
+      len = Blockly.utils.string.shortestStringLength(['Hello World']);
+      assertEquals('List of one', 11, len);
+      len = Blockly.utils.string.shortestStringLength([]);
+      assertEquals('Empty list', 0, len);
+    });
 
-  test('removeClass', function() {
-    var p = document.createElement('p');
-    p.className = ' one three  two three  ';
-    Blockly.utils.removeClass(p, 'two');
-    assertEquals('Removing "two"', 'one three three', p.className);
-    Blockly.utils.removeClass(p, 'four');
-    assertEquals('Removing "four"', 'one three three', p.className);
-    Blockly.utils.removeClass(p, 'three');
-    assertEquals('Removing "three"', 'one', p.className);
-    Blockly.utils.removeClass(p, 'ne');
-    assertEquals('Removing "ne"', 'one', p.className);
-    Blockly.utils.removeClass(p, 'one');
-    assertEquals('Removing "one"', '', p.className);
-    Blockly.utils.removeClass(p, 'zero');
-    assertEquals('Removing "zero"', '', p.className);
-  });
-
-  test('shortest string length', function() {
-    var len = Blockly.utils.shortestStringLength('one,two,three,four,five'.split(','));
-    assertEquals('Length of "one"', 3, len);
-    len = Blockly.utils.shortestStringLength('one,two,three,four,five,'.split(','));
-    assertEquals('Length of ""', 0, len);
-    len = Blockly.utils.shortestStringLength(['Hello World']);
-    assertEquals('List of one', 11, len);
-    len = Blockly.utils.shortestStringLength([]);
-    assertEquals('Empty list', 0, len);
-  });
-
-  test('comment word prefix', function() {
-    var len = Blockly.utils.commonWordPrefix('one,two,three,four,five'.split(','));
-    assertEquals('No prefix', 0, len);
-    len = Blockly.utils.commonWordPrefix('Xone,Xtwo,Xthree,Xfour,Xfive'.split(','));
-    assertEquals('No word prefix', 0, len);
-    len = Blockly.utils.commonWordPrefix('abc de,abc de,abc de,abc de'.split(','));
-    assertEquals('Full equality', 6, len);
-    len = Blockly.utils.commonWordPrefix('abc deX,abc deY'.split(','));
-    assertEquals('One word prefix', 4, len);
-    len = Blockly.utils.commonWordPrefix('abc de,abc deY'.split(','));
-    assertEquals('Overflow no', 4, len);
-    len = Blockly.utils.commonWordPrefix('abc de,abc de Y'.split(','));
-    assertEquals('Overflow yes', 6, len);
-    len = Blockly.utils.commonWordPrefix(['Hello World']);
-    assertEquals('List of one', 11, len);
-    len = Blockly.utils.commonWordPrefix([]);
-    assertEquals('Empty list', 0, len);
-    len = Blockly.utils.commonWordPrefix('turn left,turn right'.split(','));
-    assertEquals('No prefix due to  ', 0, len);
-    len = Blockly.utils.commonWordPrefix('turn\u00A0left,turn\u00A0right'.split(','));
-    assertEquals('No prefix due to \\u00A0', 0, len);
+    test('comment word prefix', function() {
+      var len = Blockly.utils.string.commonWordPrefix('one,two,three,four,five'.split(','));
+      assertEquals('No prefix', 0, len);
+      len = Blockly.utils.string.commonWordPrefix('Xone,Xtwo,Xthree,Xfour,Xfive'.split(','));
+      assertEquals('No word prefix', 0, len);
+      len = Blockly.utils.string.commonWordPrefix('abc de,abc de,abc de,abc de'.split(','));
+      assertEquals('Full equality', 6, len);
+      len = Blockly.utils.string.commonWordPrefix('abc deX,abc deY'.split(','));
+      assertEquals('One word prefix', 4, len);
+      len = Blockly.utils.string.commonWordPrefix('abc de,abc deY'.split(','));
+      assertEquals('Overflow no', 4, len);
+      len = Blockly.utils.string.commonWordPrefix('abc de,abc de Y'.split(','));
+      assertEquals('Overflow yes', 6, len);
+      len = Blockly.utils.string.commonWordPrefix(['Hello World']);
+      assertEquals('List of one', 11, len);
+      len = Blockly.utils.string.commonWordPrefix([]);
+      assertEquals('Empty list', 0, len);
+      len = Blockly.utils.string.commonWordPrefix('turn left,turn right'.split(','));
+      assertEquals('No prefix due to  ', 0, len);
+      len = Blockly.utils.string.commonWordPrefix('turn\u00A0left,turn\u00A0right'.split(','));
+      assertEquals('No prefix due to \\u00A0', 0, len);
+    });
   });
 });