diff --git a/tests/mocha/index.html b/tests/mocha/index.html
index 71b7de6b4..ef3384da9 100644
--- a/tests/mocha/index.html
+++ b/tests/mocha/index.html
@@ -25,6 +25,8 @@
     <script src="../../blocks/math.js"></script>
     <script src="../../blocks/procedures.js"></script>
     <script src="../../blocks/text.js"></script>
+    <script src="../../blocks/variables.js"></script>
+    <script src="../../blocks/variables_dynamic.js"></script>
   </head>
   <style>
     #blocklyDiv {
@@ -90,6 +92,7 @@
     <script src="procedures_test_helpers.js"></script>
     <script src="procedures_test.js"></script>
     <script src="registry_test.js"></script>
+    <script src="serializer_test.js"></script>
     <script src="theme_test.js"></script>
     <script src="toolbox_test.js"></script>
     <script src="tooltip_test.js"></script>
diff --git a/tests/mocha/serializer_test.js b/tests/mocha/serializer_test.js
new file mode 100644
index 000000000..cfac118ae
--- /dev/null
+++ b/tests/mocha/serializer_test.js
@@ -0,0 +1,1760 @@
+/**
+ * @license
+ * Copyright 2021 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+
+// TODO: Move this into samples as part of the dev-tools package.
+// TODO: Fix up typing of SerializerTestCase & SerializerTestSuite to match
+//     decision in google/blockly-samples#819.
+/**
+ * Constructs a serializer test.
+ * @param {string} title The title of this testcase.
+ * @param {string} xml The XML to use for the round-trip test.
+ * @constructor
+ * @implements {TestCase}
+ */
+function SerializerTestCase(title, xml) {
+  this.title = title;
+  this.xml = xml;
+}
+SerializerTestCase.prototype = new testHelpers.TestCase();
+
+/**
+ * The XML we want to ensure round-trips through the serializer.
+ */
+SerializerTestCase.prototype.xml = '';
+
+
+/**
+ * Constructs a serializer test suite.
+ * @param {string} title The title of this test suite.
+ * @extends {TestSuite<SerializerTestCase, SerializerTestSuite>}
+ */
+function SerializerTestSuite(title) {
+  this.title = title;
+}
+SerializerTestSuite.prototype = new testHelpers.TestSuite();
+
+var Serializer = new SerializerTestSuite('Serializer');
+
+// TODO: Make sure all of these properties are documented ad exported properly.
+Serializer.Empty = new SerializerTestCase('Empty',
+    '<xml xmlns="https://developers.google.com/blockly/xml"></xml>'
+);
+Serializer.Data = new SerializerTestCase('Data',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" editable="false" x="42" y="42">' +
+    '<data>test data</data>' +
+    '</block>' +
+    '</xml>');
+Serializer.testCases = [
+  Serializer.Empty,
+  Serializer.Data,
+];
+
+Serializer.Attributes = new SerializerTestSuite('Attributes');
+Serializer.Attributes.Basic = new SerializerTestCase('Basic',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Collapsed = new SerializerTestCase('Collapsed',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" collapsed="true" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Disabled = new SerializerTestCase('Disabled',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" disabled="true" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Deletable = new SerializerTestCase('Deletable',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" deletable="false" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Movable = new SerializerTestCase('Movable',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" movable="false" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Editable = new SerializerTestCase('Editable',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" editable="false" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.testCases = [
+  Serializer.Attributes.Basic,
+  Serializer.Attributes.Collapsed,
+  Serializer.Attributes.Disabled,
+  Serializer.Attributes.Deletable,
+  Serializer.Attributes.Movable,
+  Serializer.Attributes.Editable,
+];
+
+Serializer.Attributes.Inline = new SerializerTestSuite('Inline');
+Serializer.Attributes.Inline.True = new SerializerTestCase('True',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" inline="true" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Inline.False = new SerializerTestCase('False',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" inline="false" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Inline.testCases = [
+  Serializer.Attributes.Inline.True,
+  Serializer.Attributes.Inline.False,
+];
+
+Serializer.Attributes.Coordinates = new SerializerTestSuite('Coordinates');
+Serializer.Attributes.Coordinates.Simple = new SerializerTestCase('Simple',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Coordinates.Negative = new SerializerTestCase('Negative',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="-42" y="-42"></block>' +
+    '</xml>');
+Serializer.Attributes.Coordinates.Zero = new SerializerTestCase('Zero',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="0" y="0"></block>' +
+    '</xml>');
+Serializer.Attributes.Coordinates.testCases = [
+  Serializer.Attributes.Coordinates.Simple,
+  Serializer.Attributes.Coordinates.Negative,
+  Serializer.Attributes.Coordinates.Zero,
+];
+
+Serializer.Attributes.Id = new SerializerTestSuite('Ids');
+
+Serializer.Attributes.Id.Length = new SerializerTestSuite('Length');
+Serializer.Attributes.Id.Length.Short = new SerializerTestCase('Short',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Id.Length.Long = new SerializerTestCase('Long',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id***********************" x="42" y="42">' +
+    '</block>' +
+    '</xml>');
+Serializer.Attributes.Id.Length.testCases = [
+  Serializer.Attributes.Id.Length.Short,
+  Serializer.Attributes.Id.Length.Long,
+];
+
+Serializer.Attributes.Id.Chars = new SerializerTestSuite('Chars');
+Serializer.Attributes.Id.Chars.Symbols = new SerializerTestCase('Symbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="!#$%()*+,-./:;=?@[]^" x="42" y="42"></block>' +
+    '<block type="logic_negate" id="_`{|}~!!!!!!!!!!!!!!" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Id.Chars.Uppercase = new SerializerTestCase('Uppercase',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="ABCDEFGHIJKLMNOPQRST" x="42" y="42"></block>' +
+    '<block type="logic_negate" id="TUVWXYZAAAAAAAAAAAAA" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Id.Chars.Lowercase = new SerializerTestCase('Lowercase',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="abcdefghijklmnopqrst" x="42" y="42"></block>' +
+    '<block type="logic_negate" id="tuvwxyzaaaaaaaaaaaaa" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Id.Chars.Numbers = new SerializerTestCase('Numbers',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="01234567890000000000" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Attributes.Id.Chars.testCases = [
+  Serializer.Attributes.Id.Chars.Symbols,
+  Serializer.Attributes.Id.Chars.Uppercase,
+  Serializer.Attributes.Id.Chars.Lowercase,
+  Serializer.Attributes.Id.Chars.Numbers,
+];
+
+Serializer.Attributes.Id.testSuites = [
+  Serializer.Attributes.Id.Length,
+  Serializer.Attributes.Id.Chars,
+];
+
+Serializer.Attributes.testSuites = [
+  Serializer.Attributes.Inline,
+  Serializer.Attributes.Coordinates,
+  Serializer.Attributes.Id,
+];
+
+Serializer.Fields = new SerializerTestSuite('Fields');
+
+Serializer.Fields.Angle = new SerializerTestSuite('Angle');
+Serializer.Fields.Angle.Simple = new SerializerTestCase('Simple',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_angle" id="id******************" x="42" y="42">' +
+    '<field name="FIELDNAME">90</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Angle.Negative = new SerializerTestCase(
+    'Negative',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_angles_wrap" id="id******************" x="42" y="42">' +
+    '<field name="FIELDNAME">-90</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Angle.Decimals = new SerializerTestCase('Decimals',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_angle" id="id******************" x="42" y="42">' +
+    '<field name="FIELDNAME">1.5</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Angle.MaxPrecision = new SerializerTestCase(
+    'MaxPrecision',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_angle" id="id******************" x="42" y="42">' +
+    '<field name="FIELDNAME">1.000000000000001</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Angle.SmallestNumber = new SerializerTestCase(
+    'SmallestNumber',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_angle" id="id******************" x="42" y="42">' +
+    '<field name="FIELDNAME">5e-324</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Angle.testCases = [
+  Serializer.Fields.Angle.Simple,
+  Serializer.Fields.Angle.Negative,
+  Serializer.Fields.Angle.Decimals,
+  Serializer.Fields.Angle.MaxPrecision,
+  Serializer.Fields.Angle.SmallestNumber,
+];
+
+Serializer.Fields.Checkbox = new SerializerTestSuite('Checkbox');
+Serializer.Fields.Checkbox.True = new SerializerTestCase('True',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_checkbox" id="id******************" x="42" y="42">' +
+    '<field name="CHECKBOX">TRUE</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Checkbox.False = new SerializerTestCase('False',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_checkbox" id="id******************" x="42" y="42">' +
+    '<field name="CHECKBOX">FALSE</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Checkbox.testCases = [
+  Serializer.Fields.Checkbox.True,
+  Serializer.Fields.Checkbox.False,
+];
+
+Serializer.Fields.Colour = new SerializerTestSuite('Colour');
+Serializer.Fields.Colour.ThreeChar = new SerializerTestCase('ThreeChar',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_colour" id="id******************" x="42" y="42">' +
+    '<field name="COLOUR">#ffcc00</field>' +  // Could use a 3 char code.
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Colour.SixChar = new SerializerTestCase('SixChar',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_colour" id="id******************" x="42" y="42">' +
+    '<field name="COLOUR">#f1c101</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Colour.Black = new SerializerTestCase('Black',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_colour" id="id******************" x="42" y="42">' +
+    '<field name="COLOUR">#000000</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Colour.testCases = [
+  Serializer.Fields.Colour.ThreeChar,
+  Serializer.Fields.Colour.SixChar,
+  Serializer.Fields.Colour.Black,
+];
+
+Serializer.Fields.Dropdown = new SerializerTestSuite('Dropdown');
+Serializer.Fields.Dropdown.Default = new SerializerTestCase('Default',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_dropdowns_long" id="id******************" x="42" y="42">' +
+    '<field name="FIELDNAME">ITEM1</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Dropdown.NotDefault = new SerializerTestCase('NotDefault',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_dropdowns_long" id="id******************" x="42" y="42">' +
+    '<field name="FIELDNAME">ITEM32</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Dropdown.testCases = [
+  Serializer.Fields.Dropdown.Default,
+  Serializer.Fields.Dropdown.NotDefault,
+];
+
+
+Serializer.Fields.LabelSerializable = new SerializerTestSuite(
+    'LabelSerializable');
+Serializer.Fields.LabelSerializable.Simple = new SerializerTestCase('Simple',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">test</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.Symbols = new SerializerTestCase('Symbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">~`!@#$%^*()_+-={[}]|\\:;,.?/</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.EscapedSymbols = new SerializerTestCase(
+    'EscapedSymbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">&amp;&lt;&gt;</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.SingleQuotes = new SerializerTestCase(
+    'SingleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">\'test\'</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.DoubleQuotes = new SerializerTestCase(
+    'DoubleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">"test"</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.Numbers = new SerializerTestCase(
+    'Numbers',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">1234567890a123a123a</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.Emoji = new SerializerTestCase(
+    'Emoji',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">😀👋🏿👋🏾👋🏽👋🏼👋🏻😀❤❤❤</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.Russian = new SerializerTestCase(
+    'Russian',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">ты любопытный кот</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.Japanese = new SerializerTestCase(
+    'Japanese',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">あなたは好奇心旺盛な猫です</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.Zalgo = new SerializerTestCase(
+    'Zalgo',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">z̴̪͈̲̜͕̽̈̀͒͂̓̋̉̍a̸̧̧̜̻̘̤̫̱̲͎̞̻͆̋ļ̸̛̖̜̳͚̖͔̟̈́͂̉̀͑̑͑̎ǵ̸̫̳̽̐̃̑̚̕o̶͇̫͔̮̼̭͕̹̘̬͋̀͆̂̇̋͊̒̽</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.ControlChars = new SerializerTestCase(
+    'ControlChars',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_label_serializable" id="id******************" x="42" y="42">' +
+    '<field name="LABEL">&#x01;&#xa1;</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.LabelSerializable.testCases = [
+  Serializer.Fields.LabelSerializable.Simple,
+  Serializer.Fields.LabelSerializable.Symbols,
+  Serializer.Fields.LabelSerializable.EscapedSymbols,
+  Serializer.Fields.LabelSerializable.SingleQuotes,
+  Serializer.Fields.LabelSerializable.DoubleQuotes,
+  Serializer.Fields.LabelSerializable.Numbers,
+  Serializer.Fields.LabelSerializable.Emoji,
+  Serializer.Fields.LabelSerializable.Russian,
+  Serializer.Fields.LabelSerializable.Japanese,
+  Serializer.Fields.LabelSerializable.Zalgo,
+  // TODO: Uncoment once #4945 is merged.
+  // Serializer.Fields.LabelSerializable.ControlChars,
+];
+
+Serializer.Fields.MultilineInput = new SerializerTestSuite('MultilineInput');
+Serializer.Fields.MultilineInput.SingleLine = new SerializerTestCase(
+    'SingleLine',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">test</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.MultipleLines = new SerializerTestCase(
+    'MultipleLines',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">line1&amp;#10;line2&amp;#10;line3</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.Indentation = new SerializerTestCase(
+    'Indentation',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">line1&amp;#10;  line2&amp;#10;  line3</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.Tabs = new SerializerTestCase(
+    'Tabs',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">' +
+    'line1&amp;#10;	line2&amp;#10;	line3' +
+    '</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.Symbols = new SerializerTestCase('Symbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">~`!@#$%^*()_+-={[}]|\\:;,.?/</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.EscapedSymbols = new SerializerTestCase(
+    'EscapedSymbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">&amp;&lt;&gt;</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.SingleQuotes = new SerializerTestCase(
+    'SingleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">\'test\'</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.DoubleQuotes = new SerializerTestCase(
+    'DoubleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">"test"</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.Numbers = new SerializerTestCase(
+    'Numbers',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">1234567890a123a123a</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.Emoji = new SerializerTestCase(
+    'Emoji',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">😀👋🏿👋🏾👋🏽👋🏼👋🏻😀❤❤❤</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.Russian = new SerializerTestCase(
+    'Russian',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">ты любопытный кот</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.Japanese = new SerializerTestCase(
+    'Japanese',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">あなたは好奇心旺盛な猫です</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.Zalgo = new SerializerTestCase(
+    'Zalgo',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">z̴̪͈̲̜͕̽̈̀͒͂̓̋̉̍a̸̧̧̜̻̘̤̫̱̲͎̞̻͆̋ļ̸̛̖̜̳͚̖͔̟̈́͂̉̀͑̑͑̎ǵ̸̫̳̽̐̃̑̚̕o̶͇̫͔̮̼̭͕̹̘̬͋̀͆̂̇̋͊̒̽</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.ControlChars = new SerializerTestCase(
+    'ControlChars',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_multilinetext" id="id******************" x="42" y="42">' +
+    '<field name="CODE">&#x01;&#xa1;</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.MultilineInput.testCases = [
+  Serializer.Fields.MultilineInput.SingleLine,
+  Serializer.Fields.MultilineInput.MultipleLines,
+  Serializer.Fields.MultilineInput.Indentation,
+  Serializer.Fields.MultilineInput.Tabs,
+  Serializer.Fields.MultilineInput.Symbols,
+  Serializer.Fields.MultilineInput.EscapedSymbols,
+  Serializer.Fields.MultilineInput.SingleQuotes,
+  Serializer.Fields.MultilineInput.DoubleQuotes,
+  Serializer.Fields.MultilineInput.Numbers,
+  Serializer.Fields.MultilineInput.Emoji,
+  Serializer.Fields.MultilineInput.Russian,
+  Serializer.Fields.MultilineInput.Japanese,
+  Serializer.Fields.MultilineInput.Zalgo,
+  // TODO: Uncoment once #4945 is merged.
+  // Serializer.Fields.MultilineInput.ControlChars,
+];
+
+Serializer.Fields.Number = new SerializerTestSuite('Number');
+Serializer.Fields.Number.Simple = new SerializerTestCase('Simple',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_numbers_float" id="id******************" x="42" y="42">' +
+    '<field name="NUM">123</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Number.Negative = new SerializerTestCase('Negative',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_numbers_float" id="id******************" x="42" y="42">' +
+    '<field name="NUM">-123</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Number.PosInfinity = new SerializerTestCase('PosInfinity',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_numbers_float" id="id******************" x="42" y="42">' +
+    '<field name="NUM">Infinity</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Number.NegInfinity = new SerializerTestCase('NegInfinity',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_numbers_float" id="id******************" x="42" y="42">' +
+    '<field name="NUM">-Infinity</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Number.Decimals = new SerializerTestCase('Decimals',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_numbers_float" id="id******************" x="42" y="42">' +
+    '<field name="NUM">1.5</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Number.Smallest = new SerializerTestCase('Smallest',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_numbers_float" id="id******************" x="42" y="42">' +
+    '<field name="NUM">5e-324</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Number.Largest = new SerializerTestCase('Largest',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_numbers_float" id="id******************" x="42" y="42">' +
+    '<field name="NUM">1.7976931348623157e+308</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Number.MaxPrecisionSmall = new SerializerTestCase(
+    'MaxPrecisionSmall',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_numbers_float" id="id******************" x="42" y="42">' +
+    '<field name="NUM">1.000000000000001</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Number.MaxPrecisionLarge = new SerializerTestCase(
+    'MaxPrecisionLarge',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_numbers_float" id="id******************" x="42" y="42">' +
+    '<field name="NUM">1000000000000001</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Number.testCases = [
+  Serializer.Fields.Number.Simple,
+  Serializer.Fields.Number.Negative,
+  Serializer.Fields.Number.PosInfinity,
+  Serializer.Fields.Number.NegInfinity,
+  Serializer.Fields.Number.Decimals,
+  Serializer.Fields.Number.Smallest,
+  Serializer.Fields.Number.Largest,
+  Serializer.Fields.Number.MaxPrecisionSmall,
+  Serializer.Fields.Number.MaxPrecisionLarge,
+];
+
+Serializer.Fields.TextInput = new SerializerTestSuite('TextInput');
+Serializer.Fields.TextInput.Simple = new SerializerTestCase('Simple',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">test</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.Tabs = new SerializerTestCase('Tabs',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">line1	line2	line3</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.Symbols = new SerializerTestCase('Symbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">~`!@#$%^*()_+-={[}]|\\:;,.?/</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.EscapedSymbols = new SerializerTestCase(
+    'EscapedSymbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">&amp;&lt;&gt;</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.SingleQuotes = new SerializerTestCase(
+    'SingleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">\'test\'</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.DoubleQuotes = new SerializerTestCase(
+    'DoubleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">"test"</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.Numbers = new SerializerTestCase(
+    'Numbers',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">1234567890a123a123a</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.Emoji = new SerializerTestCase(
+    'Emoji',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">😀👋🏿👋🏾👋🏽👋🏼👋🏻😀❤❤❤</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.Russian = new SerializerTestCase(
+    'Russian',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">ты любопытный кот</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.Japanese = new SerializerTestCase(
+    'Japanese',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">あなたは好奇心旺盛な猫です</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.Zalgo = new SerializerTestCase(
+    'Zalgo',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">z̴̪͈̲̜͕̽̈̀͒͂̓̋̉̍a̸̧̧̜̻̘̤̫̱̲͎̞̻͆̋ļ̸̛̖̜̳͚̖͔̟̈́͂̉̀͑̑͑̎ǵ̸̫̳̽̐̃̑̚̕o̶͇̫͔̮̼̭͕̹̘̬͋̀͆̂̇̋͊̒̽</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.ControlChars = new SerializerTestCase(
+    'ControlChars',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="test_fields_text_input" id="id******************" x="42" y="42">' +
+    '<field name="TEXT_INPUT">&#x01;&#xa1;</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.TextInput.testCases = [
+  Serializer.Fields.TextInput.Simple,
+  Serializer.Fields.TextInput.Tabs,
+  Serializer.Fields.TextInput.Symbols,
+  Serializer.Fields.TextInput.EscapedSymbols,
+  Serializer.Fields.TextInput.SingleQuotes,
+  Serializer.Fields.TextInput.DoubleQuotes,
+  Serializer.Fields.TextInput.Numbers,
+  Serializer.Fields.TextInput.Emoji,
+  Serializer.Fields.TextInput.Russian,
+  Serializer.Fields.TextInput.Japanese,
+  Serializer.Fields.TextInput.Zalgo,
+  // TODO: Uncoment once #4945 is merged.
+  // Serializer.Fields.TextInput.ControlChars,
+];
+
+Serializer.Fields.Variable = new SerializerTestSuite('Variable');
+Serializer.Fields.Variable.Simple = new SerializerTestCase('Simple',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">test</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">test</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Types = new SerializerTestCase('Types',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable type="String" id="aaaaaaaaaaaaaaaaaaaa">test</variable>' +
+    '<variable type="Number" id="bbbbbbbbbbbbbbbbbbbb">test2</variable>' +
+    '<variable type="Colour" id="cccccccccccccccccccc">test3</variable>' +
+    '</variables>' +
+    '<block type="variables_get_dynamic" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa" variabletype="String">test</field>' +
+    '</block>' +
+    '<block type="variables_get_dynamic" id="id2*****************" x="42" y="84">' +
+    '<field name="VAR" id="bbbbbbbbbbbbbbbbbbbb" variabletype="Number">test2</field>' +
+    '</block>' +
+    '<block type="variables_get_dynamic" id="id3*****************" x="42" y="106">' +
+    '<field name="VAR" id="cccccccccccccccccccc" variabletype="Colour">test3</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Tabs = new SerializerTestCase('Tabs',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">line1	line2	line3</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">line1	line2	line3</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Symbols = new SerializerTestCase('Symbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">~`!@#$%^*()_+-={[}]|\\:;,.?/</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">~`!@#$%^*()_+-={[}]|\\:;,.?/</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.EscapedSymbols = new SerializerTestCase(
+    'EscapedSymbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">&amp;&lt;&gt;</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">&amp;&lt;&gt;</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.SingleQuotes = new SerializerTestCase(
+    'SingleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">\'test\'</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">\'test\'</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.DoubleQuotes = new SerializerTestCase(
+    'DoubleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">"test"</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">"test"</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Numbers = new SerializerTestCase(
+    'Numbers',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">1234567890a123a123a</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">1234567890a123a123a</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Emoji = new SerializerTestCase(
+    'Emoji',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">😀👋🏿👋🏾👋🏽👋🏼👋🏻😀❤❤❤</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">😀👋🏿👋🏾👋🏽👋🏼👋🏻😀❤❤❤</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Russian = new SerializerTestCase(
+    'Russian',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">ты любопытный кот</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">ты любопытный кот</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Japanese = new SerializerTestCase(
+    'Japanese',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">あなたは好奇心旺盛な猫です</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">あなたは好奇心旺盛な猫です</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Zalgo = new SerializerTestCase(
+    'Zalgo',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">z̴̪͈̲̜͕̽̈̀͒͂̓̋̉̍a̸̧̧̜̻̘̤̫̱̲͎̞̻͆̋ļ̸̛̖̜̳͚̖͔̟̈́͂̉̀͑̑͑̎ǵ̸̫̳̽̐̃̑̚̕o̶͇̫͔̮̼̭͕̹̘̬͋̀͆̂̇̋͊̒̽</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">z̴̪͈̲̜͕̽̈̀͒͂̓̋̉̍a̸̧̧̜̻̘̤̫̱̲͎̞̻͆̋ļ̸̛̖̜̳͚̖͔̟̈́͂̉̀͑̑͑̎ǵ̸̫̳̽̐̃̑̚̕o̶͇̫͔̮̼̭͕̹̘̬͋̀͆̂̇̋͊̒̽</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.ControlChars = new SerializerTestCase(
+    'ControlChars',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">&#x01;&#xa1;</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="aaaaaaaaaaaaaaaaaaaa">&#x01;&#xa1;</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.testCases = [
+  Serializer.Fields.Variable.Simple,
+  Serializer.Fields.Variable.Types,
+  Serializer.Fields.Variable.Tabs,
+  Serializer.Fields.Variable.Symbols,
+  Serializer.Fields.Variable.EscapedSymbols,
+  Serializer.Fields.Variable.SingleQuotes,
+  Serializer.Fields.Variable.DoubleQuotes,
+  Serializer.Fields.Variable.Numbers,
+  Serializer.Fields.Variable.Emoji,
+  Serializer.Fields.Variable.Russian,
+  Serializer.Fields.Variable.Japanese,
+  Serializer.Fields.Variable.Zalgo,
+  // TODO: Uncoment once #4945 is merged.
+  // Serializer.Fields.Variable.ControlChars,
+];
+
+Serializer.Fields.Variable.Id = new SerializerTestSuite('Id');
+
+Serializer.Fields.Variable.Id.Length = new SerializerTestSuite('Length');
+Serializer.Fields.Variable.Id.Length.Short = new SerializerTestCase('Short',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="id">test</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="id">test</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Id.Length.Long = new SerializerTestCase('Long',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="id***********************">test</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="id***********************">test</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Id.Length.testCases = [
+  Serializer.Fields.Variable.Id.Length.Short,
+  Serializer.Fields.Variable.Id.Length.Long,
+];
+
+Serializer.Fields.Variable.Id.Chars = new SerializerTestSuite('Chars');
+Serializer.Fields.Variable.Id.Chars.Symbols = new SerializerTestCase('Symbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="!#$%()*+,-./:;=?@[]^">test</variable>' +
+    '<variable id="_`{|}~!!!!!!!!!!!!!!">test2</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="!#$%()*+,-./:;=?@[]^">test</field>' +
+    '</block>' +
+    '<block type="variables_get" id="id1*****************" x="42" y="42">' +
+    '<field name="VAR" id="_`{|}~!!!!!!!!!!!!!!">test2</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Id.Chars.Uppercase = new SerializerTestCase('Uppercase',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="ABCDEFGHIJKLMNOPQRST">test</variable>' +
+    '<variable id="TUVWXYZAAAAAAAAAAAAA">test2</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="ABCDEFGHIJKLMNOPQRST">test</field>' +
+    '</block>' +
+    '<block type="variables_get" id="id1*****************" x="42" y="42">' +
+    '<field name="VAR" id="TUVWXYZAAAAAAAAAAAAA">test2</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Id.Chars.Lowercase = new SerializerTestCase('Lowercase',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="abcdefghijklmnopqrst">test</variable>' +
+    '<variable id="tuvwxyzaaaaaaaaaaaaa">test2</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="abcdefghijklmnopqrst">test</field>' +
+    '</block>' +
+    '<block type="variables_get" id="id1*****************" x="42" y="42">' +
+    '<field name="VAR" id="tuvwxyzaaaaaaaaaaaaa">test2</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Id.Chars.Numbers = new SerializerTestCase('Numbers',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="01234567890000000000">test</variable>' +
+    '</variables>' +
+    '<block type="variables_get" id="id******************" x="42" y="42">' +
+    '<field name="VAR" id="01234567890000000000">test</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Fields.Variable.Id.Chars.testCases = [
+  Serializer.Fields.Variable.Id.Chars.Symbols,
+  Serializer.Fields.Variable.Id.Chars.Uppercase,
+  Serializer.Fields.Variable.Id.Chars.Lowercase,
+  Serializer.Fields.Variable.Id.Chars.Numbers,
+];
+
+Serializer.Fields.Variable.Id.testSuites = [
+  Serializer.Fields.Variable.Id.Length,
+  Serializer.Fields.Variable.Id.Chars,
+];
+
+Serializer.Fields.Variable.testSuites = [
+  Serializer.Fields.Variable.Id,
+];
+
+Serializer.Fields.testSuites = [
+  Serializer.Fields.Angle,
+  Serializer.Fields.Checkbox,
+  Serializer.Fields.Colour,
+  Serializer.Fields.Dropdown,
+  Serializer.Fields.LabelSerializable,
+  Serializer.Fields.MultilineInput,
+  Serializer.Fields.Number,
+  Serializer.Fields.TextInput,
+  Serializer.Fields.Variable,
+];
+
+Serializer.Icons = new SerializerTestSuite('Icons');
+
+Serializer.Icons.Comment = new SerializerTestSuite('Comment');
+Serializer.Icons.Comment.Basic = new SerializerTestCase('Basic',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">test</comment>' +
+    '</block>' +
+    '</xml>');
+
+Serializer.Icons.Comment.Size = new SerializerTestSuite('Size');
+Serializer.Icons.Comment.Size.Different = new SerializerTestCase('Different',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="160" w="80">test</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Size.Large = new SerializerTestCase('Large',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="10000" w="10000">test</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Size.testCases = [
+  Serializer.Icons.Comment.Size.Different,
+  Serializer.Icons.Comment.Size.Large,
+];
+
+Serializer.Icons.Comment.Pinned = new SerializerTestSuite('Pinned');
+Serializer.Icons.Comment.Pinned.True = new SerializerTestCase('True',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="true" h="80" w="160">test</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Pinned.False = new SerializerTestCase('False',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">test</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Pinned.testCases = [
+  Serializer.Icons.Comment.Pinned.True,
+  Serializer.Icons.Comment.Pinned.False,
+];
+
+Serializer.Icons.Comment.Text = new SerializerTestSuite('Text');
+Serializer.Icons.Comment.Text.Symbols = new SerializerTestCase('Symbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">~`!@#$%^*()_+-={[}]|\\:;,.?/</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Text.EscapedSymbols = new SerializerTestCase(
+    'EscapedSymbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">&amp;&lt;&gt;</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Text.SingleQuotes = new SerializerTestCase(
+    'SingleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">\'test\'</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Text.DoubleQuotes = new SerializerTestCase(
+    'DoubleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">"test"</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Text.Numbers = new SerializerTestCase(
+    'Numbers',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">1234567890a123a123a</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Text.Emoji = new SerializerTestCase(
+    'Emoji',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">😀👋🏿👋🏾👋🏽👋🏼👋🏻😀❤❤❤</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Text.Russian = new SerializerTestCase(
+    'Russian',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">ты любопытный кот</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Text.Japanese = new SerializerTestCase(
+    'Japanese',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">あなたは好奇心旺盛な猫です</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Text.Zalgo = new SerializerTestCase(
+    'Zalgo',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">z̴̪͈̲̜͕̽̈̀͒͂̓̋̉̍a̸̧̧̜̻̘̤̫̱̲͎̞̻͆̋ļ̸̛̖̜̳͚̖͔̟̈́͂̉̀͑̑͑̎ǵ̸̫̳̽̐̃̑̚̕o̶͇̫͔̮̼̭͕̹̘̬͋̀͆̂̇̋͊̒̽</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Text.ControlChars = new SerializerTestCase(
+    'ControlChars',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<comment pinned="false" h="80" w="160">&#x01;&#xa1;</comment>' +
+    '</block>' +
+    '</xml>');
+Serializer.Icons.Comment.Text.testCases = [
+  Serializer.Icons.Comment.Text.Symbols,
+  Serializer.Icons.Comment.Text.EscapedSymbols,
+  Serializer.Icons.Comment.Text.SingleQuotes,
+  Serializer.Icons.Comment.Text.DoubleQuotes,
+  Serializer.Icons.Comment.Text.Numbers,
+  Serializer.Icons.Comment.Text.Emoji,
+  Serializer.Icons.Comment.Text.Russian,
+  Serializer.Icons.Comment.Text.Japanese,
+  Serializer.Icons.Comment.Text.Zalgo,
+  // TODO: Uncoment once #4945 is merged.
+  // Serializer.Icons.Comment.Text.ControlChars,
+];
+
+Serializer.Icons.Comment.testSuites = [
+  Serializer.Icons.Comment.Size,
+  Serializer.Icons.Comment.Pinned,
+  Serializer.Icons.Comment.Text,
+];
+
+Serializer.Icons.Comment.testCases = [
+  Serializer.Icons.Comment.Basic,
+];
+
+Serializer.Icons.testSuites = [Serializer.Icons.Comment];
+
+Serializer.Connections = new SerializerTestSuite('Connections');
+
+Serializer.Connections.Child = new SerializerTestSuite('Child');
+Serializer.Connections.Child.Value = new SerializerTestCase('Value',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<value name="BOOL">' +
+    '<block type="logic_boolean" id="id2*****************">' +
+    '<field name="BOOL">TRUE</field>' +
+    '</block>' +
+    '</value>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Child.Statement = new SerializerTestCase('Statement',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_repeat_ext" id="id******************" x="42" y="42">' +
+    '<statement name="DO">' +
+    '<block type="text_print" id="id2*****************"></block>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Child.Next = new SerializerTestCase('Next',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_print" id="id******************" x="42" y="42">' +
+    '<next>' +
+    '<block type="text_print" id="id2*****************"></block>' +
+    '</next>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Child.Row = new SerializerTestCase('Row',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<value name="BOOL">' +
+    '<block type="logic_negate" id="id2*****************">' +
+    '<value name="BOOL">' +
+    '<block type="logic_boolean" id="id3*****************">' +
+    '<field name="BOOL">TRUE</field>' +
+    '</block>' +
+    '</value>' +
+    '</block>' +
+    '</value>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Child.Nested = new SerializerTestCase('Nested',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_repeat_ext" id="id******************" x="42" y="42">' +
+    '<statement name="DO">' +
+    '<block type="controls_repeat_ext" id="id2*****************">' +
+    '<statement name="DO">' +
+    '<block type="text_print" id="id3*****************"></block>' +
+    '</statement>' +
+    '</block>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Child.Stack = new SerializerTestCase('Stack',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_print" id="id******************" x="42" y="42">' +
+    '<next>' +
+    '<block type="text_print" id="id2*****************">' +
+    '<next>' +
+    '<block type="text_print" id="id3*****************"></block>' +
+    '</next>' +
+    '</block>' +
+    '</next>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Child.testCases = [
+  Serializer.Connections.Child.Value,
+  Serializer.Connections.Child.Statement,
+  Serializer.Connections.Child.Next,
+  Serializer.Connections.Child.Row,
+  Serializer.Connections.Child.Nested,
+  Serializer.Connections.Child.Stack,
+];
+
+Serializer.Connections.Shadow = new SerializerTestSuite('Shadow');
+Serializer.Connections.Shadow.Value = new SerializerTestCase('Value',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<value name="BOOL">' +
+    '<shadow type="logic_boolean" id="id2*****************">' +
+    '<field name="BOOL">TRUE</field>' +
+    '</shadow>' +
+    '</value>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Shadow.Statement = new SerializerTestCase('Statement',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_repeat_ext" id="id******************" x="42" y="42">' +
+    '<statement name="DO">' +
+    '<shadow type="text_print" id="id2*****************"></shadow>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Shadow.Next = new SerializerTestCase('Next',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_print" id="id******************" x="42" y="42">' +
+    '<next>' +
+    '<shadow type="text_print" id="id2*****************"></shadow>' +
+    '</next>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Shadow.Row = new SerializerTestCase('Row',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<value name="BOOL">' +
+    '<shadow type="logic_negate" id="id2*****************">' +
+    '<value name="BOOL">' +
+    '<shadow type="logic_boolean" id="id3*****************">' +
+    '<field name="BOOL">TRUE</field>' +
+    '</shadow>' +
+    '</value>' +
+    '</shadow>' +
+    '</value>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Shadow.Nested = new SerializerTestCase('Nested',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_repeat_ext" id="id******************" x="42" y="42">' +
+    '<statement name="DO">' +
+    '<shadow type="controls_repeat_ext" id="id2*****************">' +
+    '<statement name="DO">' +
+    '<shadow type="text_print" id="id3*****************"></shadow>' +
+    '</statement>' +
+    '</shadow>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Shadow.Stack = new SerializerTestCase('Stack',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_print" id="id******************" x="42" y="42">' +
+    '<next>' +
+    '<shadow type="text_print" id="id2*****************">' +
+    '<next>' +
+    '<shadow type="text_print" id="id3*****************"></shadow>' +
+    '</next>' +
+    '</shadow>' +
+    '</next>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.Shadow.testCases = [
+  Serializer.Connections.Shadow.Value,
+  Serializer.Connections.Shadow.Statement,
+  Serializer.Connections.Shadow.Next,
+  Serializer.Connections.Shadow.Row,
+  Serializer.Connections.Shadow.Nested,
+  Serializer.Connections.Shadow.Stack,
+];
+
+Serializer.Connections.OverwrittenShadow =
+    new SerializerTestSuite('OverwrittenShadow');
+Serializer.Connections.OverwrittenShadow.Value = new SerializerTestCase(
+    'Value',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<value name="BOOL">' +
+    '<shadow type="logic_boolean" id="id2*****************">' +
+    '<field name="BOOL">TRUE</field>' +
+    '</shadow>' +
+    '<block type="logic_boolean" id="id3*****************">' +
+    '<field name="BOOL">TRUE</field>' +
+    '</block>' +
+    '</value>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.OverwrittenShadow.Statement = new SerializerTestCase(
+    'Statement',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_repeat_ext" id="id******************" x="42" y="42">' +
+    '<statement name="DO">' +
+    '<shadow type="text_print" id="id2*****************"></shadow>' +
+    '<block type="text_print" id="id3*****************"></block>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.OverwrittenShadow.Next = new SerializerTestCase('Next',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_print" id="id******************" x="42" y="42">' +
+    '<next>' +
+    '<block type="text_print" id="id2*****************"></block>' +
+    '<shadow type="text_print" id="id3*****************"></shadow>' +
+    '</next>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.OverwrittenShadow.Row = new SerializerTestCase('Row',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="logic_negate" id="id******************" x="42" y="42">' +
+    '<value name="BOOL">' +
+    '<shadow type="logic_negate" id="id2*****************">' +
+    '<value name="BOOL">' +
+    '<shadow type="logic_boolean" id="id3*****************">' +
+    '<field name="BOOL">TRUE</field>' +
+    '</shadow>' +
+    '</value>' +
+    '</shadow>' +
+    '<block type="logic_boolean" id="id3*****************">' +
+    '<field name="BOOL">TRUE</field>' +
+    '</block>' +
+    '</value>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.OverwrittenShadow.Nested = new SerializerTestCase(
+    'Nested',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_repeat_ext" id="id******************" x="42" y="42">' +
+    '<statement name="DO">' +
+    '<shadow type="controls_repeat_ext" id="id2*****************">' +
+    '<statement name="DO">' +
+    '<shadow type="text_print" id="id3*****************"></shadow>' +
+    '</statement>' +
+    '</shadow>' +
+    '<block type="text_print" id="id3*****************"></block>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.OverwrittenShadow.Stack = new SerializerTestCase('Stack',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_print" id="id******************" x="42" y="42">' +
+    '<next>' +
+    '<block type="text_print" id="id3*****************"></block>' +
+    '<shadow type="text_print" id="id2*****************">' +
+    '<next>' +
+    '<shadow type="text_print" id="id3*****************"></shadow>' +
+    '</next>' +
+    '</shadow>' +
+    '</next>' +
+    '</block>' +
+    '</xml>');
+Serializer.Connections.OverwrittenShadow.testCases = [
+  Serializer.Connections.OverwrittenShadow.Value,
+  Serializer.Connections.OverwrittenShadow.Statement,
+  Serializer.Connections.OverwrittenShadow.Next,
+  Serializer.Connections.OverwrittenShadow.Row,
+  Serializer.Connections.OverwrittenShadow.Nested,
+  Serializer.Connections.OverwrittenShadow.Stack,
+];
+
+Serializer.Connections.testSuites = [
+  Serializer.Connections.Child,
+  Serializer.Connections.Shadow,
+  Serializer.Connections.OverwrittenShadow,
+];
+
+Serializer.Mutations = new SerializerTestSuite('Mutations');
+Serializer.Mutations.MathNumberProperty = new SerializerTestCase(
+    'MathNumberProperty',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="math_number_property" id="id" x="42" y="42">' +
+    '<mutation divisor_input="true"></mutation>' +
+    '<field name="PROPERTY">DIVISIBLE_BY</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.MathOnList = new SerializerTestCase(
+    'MathOnList',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="math_on_list" id="id" x="42" y="42">' +
+    '<mutation op="MODE"></mutation>' +
+    '<field name="OP">MODE</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.TextJoin = new SerializerTestCase(
+    'TextJoin',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_join" id="id" x="42" y="42">' +
+    '<mutation items="10"></mutation>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.TextCharAt = new SerializerTestCase(
+    'TextCharAt',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_charAt" id="id" x="42" y="42">' +
+    '<mutation at="false"></mutation>' +
+    '<field name="WHERE">FIRST</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.TextGetSubstring = new SerializerTestCase(
+    'TextGetSubstring',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_getSubstring" id="id" x="42" y="42">' +
+    '<mutation at1="true" at2="false"></mutation>' +
+    '<field name="WHERE1">FROM_START</field>' +
+    '<field name="WHERE2">LAST</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.TextPromptExt = new SerializerTestCase(
+    'TextPromptExt',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_prompt_ext" id="id" x="42" y="42">' +
+    '<mutation type="NUMBER"></mutation>' +
+    '<field name="TYPE">NUMBER</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.TextPrompt = new SerializerTestCase(
+    'TextPrompt',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="text_prompt" id="id" x="42" y="42">' +
+    '<mutation type="NUMBER"></mutation>' +
+    '<field name="TYPE">NUMBER</field>' +
+    '<field name="TEXT"></field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.testCases = [
+  Serializer.Mutations.MathNumberProperty,
+  Serializer.Mutations.MathOnList,
+  Serializer.Mutations.TextJoin,
+  Serializer.Mutations.TextCharAt,
+  Serializer.Mutations.TextGetSubstring,
+  Serializer.Mutations.TextPromptExt,
+  Serializer.Mutations.TextPrompt,
+];
+
+Serializer.Mutations.ControlsIf = new SerializerTestSuite('ControlsIf');
+Serializer.Mutations.ControlsIf.NoMutation = new SerializerTestCase(
+    'NoMutation',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42"></block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.ElseIfAndElse = new SerializerTestCase(
+    'ElseIfAndElse',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation elseif="1" else="1"></mutation>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.MultipleElseIfs = new SerializerTestCase(
+    'MultipleElseIfs',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation elseif="3"></mutation>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.MutlipleElseIfsAndElse = new SerializerTestCase(
+    'MutlipleElseIfsAndElse',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation elseif="3" else="1"></mutation>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.testCases = [
+  Serializer.Mutations.ControlsIf.NoMutation,
+  Serializer.Mutations.ControlsIf.ElseIfAndElse,
+  Serializer.Mutations.ControlsIf.MultipleElseIfs,
+  Serializer.Mutations.ControlsIf.MutlipleElseIfsAndElse,
+];
+
+Serializer.Mutations.ControlsIf.ElseIf = new SerializerTestSuite('ElseIf');
+Serializer.Mutations.ControlsIf.ElseIf.NoChild = new SerializerTestCase(
+    'NoChild',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation elseif="1"></mutation>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.ElseIf.Child = new SerializerTestCase(
+    'Child',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation elseif="1"></mutation>' +
+    '<statement name="DO1">' +
+    '<block type="text_print" id="id2*****************"></block>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.ElseIf.Shadow = new SerializerTestCase(
+    'Shadow',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation elseif="1"></mutation>' +
+    '<statement name="DO1">' +
+    '<shadow type="text_print" id="id2*****************"></shadow>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.ElseIf.OverwrittenShadow = new SerializerTestCase(
+    'OverwrittenShadow',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation elseif="1"></mutation>' +
+    '<statement name="DO1">' +
+    '<shadow type="text_print" id="id2*****************"></shadow>' +
+    '<block type="text_print" id="id3*****************"></block>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.ElseIf.testCases = [
+  Serializer.Mutations.ControlsIf.ElseIf.NoChild,
+  Serializer.Mutations.ControlsIf.ElseIf.Child,
+  Serializer.Mutations.ControlsIf.ElseIf.Shadow,
+  Serializer.Mutations.ControlsIf.ElseIf.OverwrittenShadow,
+];
+
+Serializer.Mutations.ControlsIf.Else = new SerializerTestSuite('Else');
+Serializer.Mutations.ControlsIf.Else.NoChild = new SerializerTestCase(
+    'NoChild',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation else="1"></mutation>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.Else.Child = new SerializerTestCase(
+    'Child',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation else="1"></mutation>' +
+    '<statement name="ELSE">' +
+    '<block type="text_print" id="id2*****************"></block>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.Else.Shadow = new SerializerTestCase(
+    'Shadow',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation else="1"></mutation>' +
+    '<statement name="ELSE">' +
+    '<shadow type="text_print" id="id2*****************"></shadow>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.Else.OverwrittenShadow = new SerializerTestCase(
+    'OverwrittenShadow',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="controls_if" id="id******************" x="42" y="42">' +
+    '<mutation else="1"></mutation>' +
+    '<statement name="ELSE">' +
+    '<shadow type="text_print" id="id2*****************"></shadow>' +
+    '<block type="text_print" id="id3*****************"></block>' +
+    '</statement>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ControlsIf.Else.testCases = [
+  Serializer.Mutations.ControlsIf.Else.NoChild,
+  Serializer.Mutations.ControlsIf.Else.Child,
+  Serializer.Mutations.ControlsIf.Else.Shadow,
+  Serializer.Mutations.ControlsIf.Else.OverwrittenShadow,
+];
+
+Serializer.Mutations.ControlsIf.testSuites = [
+  Serializer.Mutations.ControlsIf.ElseIf,
+  Serializer.Mutations.ControlsIf.Else,
+];
+
+Serializer.Mutations.ListCreate = new SerializerTestSuite('ListCreate');
+Serializer.Mutations.ListCreate.Default = new SerializerTestCase(
+    'Default',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="lists_create_with" id="id******************" x="42" y="42">' +
+    '<mutation items="3"></mutation>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ListCreate.ZeroInputs = new SerializerTestCase(
+    'ZeroInputs',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="lists_create_with" id="id******************" x="42" y="42">' +
+    '<mutation items="0"></mutation>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ListCreate.MultipleInputs = new SerializerTestCase(
+    'MultipleInputs',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="lists_create_with" id="id******************" x="42" y="42">' +
+    '<mutation items="10"></mutation>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ListCreate.testCases = [
+  Serializer.Mutations.ListCreate.Default,
+  Serializer.Mutations.ListCreate.ZeroInputs,
+  Serializer.Mutations.ListCreate.MultipleInputs,
+];
+
+Serializer.Mutations.ListCreate.OneInput = new SerializerTestSuite('OneIput');
+Serializer.Mutations.ListCreate.OneInput.NoChild = new SerializerTestCase(
+    'NoChild',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="lists_create_with" id="id******************" x="42" y="42">' +
+    '<mutation items="1"></mutation>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ListCreate.OneInput.Child = new SerializerTestCase(
+    'Child',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="lists_create_with" id="id******************" x="42" y="42">' +
+    '<mutation items="1"></mutation>' +
+    '<value name="ADD0">' +
+    '<block type="math_random_float" id="id2*****************"></block>' +
+    '</value>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ListCreate.OneInput.Shadow = new SerializerTestCase(
+    'Shadow',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="lists_create_with" id="id******************" x="42" y="42">' +
+    '<mutation items="1"></mutation>' +
+    '<value name="ADD0">' +
+    '<shadow type="math_random_float" id="id2*****************"></shadow>' +
+    '</value>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.ListCreate.OneInput.OverwrittenShadow =
+    new SerializerTestCase(
+        'OverwrittenShadow',
+        '<xml xmlns="https://developers.google.com/blockly/xml">' +
+        '<block type="lists_create_with" id="id******************" x="42" y="42">' +
+        '<mutation items="1"></mutation>' +
+        '<value name="ADD0">' +
+        '<shadow type="math_random_float" id="id2*****************"></shadow>' +
+        '<block type="math_random_float" id="id3*****************"></block>' +
+        '</value>' +
+        '</block>' +
+        '</xml>');
+Serializer.Mutations.ListCreate.OneInput.testCases = [
+  Serializer.Mutations.ListCreate.OneInput.NoChild,
+  Serializer.Mutations.ListCreate.OneInput.Child,
+  Serializer.Mutations.ListCreate.OneInput.Shadow,
+  Serializer.Mutations.ListCreate.OneInput.OverwrittenShadow,
+];
+
+Serializer.Mutations.ListCreate.testSuites = [
+  Serializer.Mutations.ListCreate.OneInput
+];
+
+Serializer.Mutations.Procedure = new SerializerTestSuite('Procedure');
+Serializer.Mutations.Procedure.NoMutation = new SerializerTestCase('NoMutation',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">do something</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Variables = new SerializerTestCase('Variables',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<variables>' +
+    '<variable id="aaaaaaaaaaaaaaaaaaaa">x</variable>' +
+    '<variable id="bbbbbbbbbbbbbbbbbbbb">y</variable>' +
+    '<variable id="cccccccccccccccccccc">z</variable>' +
+    '</variables>' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<mutation>' +
+    '<arg name="x" varid="aaaaaaaaaaaaaaaaaaaa"></arg>' +
+    '<arg name="y" varid="bbbbbbbbbbbbbbbbbbbb"></arg>' +
+    '<arg name="z" varid="cccccccccccccccccccc"></arg>' +
+    '</mutation>' +
+    '<field name="NAME">do something</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.NoStatements = new SerializerTestCase(
+    'NoStatements',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<mutation statements="false"></mutation>' +
+    '<field name="NAME">do something</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.testCases = [
+  Serializer.Mutations.Procedure.NoMutation,
+  Serializer.Mutations.Procedure.Variables,
+  Serializer.Mutations.Procedure.NoStatements,
+];
+
+Serializer.Mutations.Procedure.Names = new SerializerTestSuite('Names');
+Serializer.Mutations.Procedure.Names.Symbols = new SerializerTestCase('Symbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">~`!@#$%^*()_+-={[}]|\\:;,.?/</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Names.EscapedSymbols = new SerializerTestCase(
+    'EscapedSymbols',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">&amp;&lt;&gt;</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Names.SingleQuotes = new SerializerTestCase(
+    'SingleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">\'test\'</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Names.DoubleQuotes = new SerializerTestCase(
+    'DoubleQuotes',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">"test"</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Names.Numbers = new SerializerTestCase(
+    'Numbers',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">1234567890a123a123a</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Names.Emoji = new SerializerTestCase(
+    'Emoji',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">😀👋🏿👋🏾👋🏽👋🏼👋🏻😀❤❤❤</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Names.Russian = new SerializerTestCase(
+    'Russian',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">ты любопытный кот</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Names.Japanese = new SerializerTestCase(
+    'Japanese',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">あなたは好奇心旺盛な猫です</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Names.Zalgo = new SerializerTestCase(
+    'Zalgo',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">z̴̪͈̲̜͕̽̈̀͒͂̓̋̉̍a̸̧̧̜̻̘̤̫̱̲͎̞̻͆̋ļ̸̛̖̜̳͚̖͔̟̈́͂̉̀͑̑͑̎ǵ̸̫̳̽̐̃̑̚̕o̶͇̫͔̮̼̭͕̹̘̬͋̀͆̂̇̋͊̒̽</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Names.ControlChars = new SerializerTestCase(
+    'ControlChars',
+    '<xml xmlns="https://developers.google.com/blockly/xml">' +
+    '<block type="procedures_defreturn" id="id******************" x="42" y="42">' +
+    '<field name="NAME">&#x01;&#xa1;</field>' +
+    '</block>' +
+    '</xml>');
+Serializer.Mutations.Procedure.Names.testCases = [
+  Serializer.Mutations.Procedure.Names.Symbols,
+  Serializer.Mutations.Procedure.Names.EscapedSymbols,
+  Serializer.Mutations.Procedure.Names.SingleQuotes,
+  Serializer.Mutations.Procedure.Names.DoubleQuotes,
+  Serializer.Mutations.Procedure.Names.Numbers,
+  Serializer.Mutations.Procedure.Names.Emoji,
+  Serializer.Mutations.Procedure.Names.Russian,
+  Serializer.Mutations.Procedure.Names.Japanese,
+  Serializer.Mutations.Procedure.Names.Zalgo,
+  // TODO: Uncoment once #4945 is merged.
+  // Serializer.Mutations.Procedure.Names.ControlChars,
+];
+
+Serializer.Mutations.Procedure.testSuites = [
+  Serializer.Mutations.Procedure.Names,
+];
+
+Serializer.Mutations.testSuites = [
+  Serializer.Mutations.ControlsIf,
+  Serializer.Mutations.ListCreate,
+  Serializer.Mutations.Procedure,
+];
+
+Serializer.testSuites = [
+  Serializer.Attributes,
+  Serializer.Fields,
+  Serializer.Icons,
+  Serializer.Connections,
+  Serializer.Mutations,
+];
+
+var runSerializerTestSuite = (serializer, deserializer, testSuite) => {
+
+  const createTestFunction = function(test) {
+    return function() {
+      Blockly.Xml.domToWorkspace(
+          Blockly.Xml.textToDom(test.xml), this.workspace);
+      if (serializer && deserializer) {
+        // TODO: Add support for custom serializeers and deserializers.
+        //    Will be added once we have the JSO format working.
+      }
+      var newXml = Blockly.Xml.workspaceToDom(this.workspace);
+      chai.assert.equal(Blockly.Xml.domToText(newXml), test.xml);
+    };
+  };
+
+  // This takes in a suite, but we don't care.
+  const createTestCaseFunction = function(_) {
+    return createTestFunction;
+  };
+
+  let suiteCall = (testSuite.skip ? suite.skip : suite);
+  suiteCall = (testSuite.only ? suite.only : suiteCall);
+
+  suiteCall(testSuite.title, function() {
+    setup(function() {
+      sharedTestSetup.call(this);
+      this.workspace = new Blockly.Workspace();
+    });
+
+    teardown(function() {
+      workspaceTeardown.call(this, this.workspace);
+      sharedTestTeardown.call(this);
+    });
+
+    testHelpers.runTestSuites(
+        testSuite.testSuites, createTestCaseFunction);
+    testHelpers.runTestCases(testSuite.testCases, createTestFunction);
+  });
+};
+
+runSerializerTestSuite(null, null, Serializer);