diff --git a/tests/blocks/test_blocks.js b/tests/blocks/test_blocks.js
index 3782ce91a..5b3da54fe 100644
--- a/tests/blocks/test_blocks.js
+++ b/tests/blocks/test_blocks.js
@@ -23,19 +23,19 @@ goog.provide('Blockly.TestBlocks');
 
 Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
   {
-    "type": "empty_block",
+    "type": "test_basic_empty",
     "message0": "",
     "args0": []
   },
   {
-    "type": "value_to_stack",
+    "type": "test_basic_value_to_stack",
     "message0": "value to stack",
     "nextStatement": null,
     "output": null,
     "style": "math_blocks"
   },
   {
-    "type": "value_to_statement",
+    "type": "test_basic_value_to_statement",
     "message0": "value to statement %1",
     "args0": [
       {
@@ -47,7 +47,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "style": "math_blocks"
   },
   {
-    "type": "limit_instances",
+    "type": "test_basic_limit_instances",
     "message0": "limit 3 instances %1 %2",
     "args0": [
       {
@@ -63,7 +63,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "style": "math_blocks",
   },
   {
-    "type": "example_dropdown_long",
+    "type": "test_fields_dropdown_long",
     "message0": "long: %1",
     "args0": [
       {
@@ -107,7 +107,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     ]
   },
   {
-    "type": "example_dropdown_images",
+    "type": "test_fields_dropdown_images",
     "message0": "%1",
     "args0": [
       {
@@ -133,7 +133,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     ]
   },
   {
-    "type": "example_dropdown_images_and_text",
+    "type": "test_fields_dropdown_images_and_text",
     "message0": "%1",
     "args0": [
       {
@@ -160,7 +160,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     ]
   },
   {
-    "type": "example_angle",
+    "type": "test_fields_angle",
     "message0": "angle: %1",
     "args0": [
       {
@@ -177,7 +177,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "colour": "230"
   },
   {
-    "type": "example_date",
+    "type": "test_fields_date",
     "message0": "date: %1",
     "args0": [
       {
@@ -193,7 +193,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     ]
   },
   {
-    "type": "test_number",
+    "type": "test_fields_number",
     "message0": "float %1",
     "args0": [
       {
@@ -207,7 +207,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "tooltip": "A number."
   },
   {
-    "type": "test_integer",
+    "type": "test_fields_integer",
     "message0": "integer %1",
     "args0": [
       {
@@ -222,7 +222,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "tooltip": "An integer."
   },
   {
-    "type": "test_number_hundredths",
+    "type": "test_fields_number_hundredths",
     "message0": "$ %1",
     "args0": [
       {
@@ -237,7 +237,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "tooltip": "A dollar amount."
   },
   {
-    "type": "test_integer_bounded",
+    "type": "test_fields_integer_bounded",
     "message0": "midi note %1",
     "args0": [
       {
@@ -254,7 +254,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "tooltip": "A midi note."
   },
   {
-    "type": "image_datauri",
+    "type": "test_images_datauri",
     "message0": "Image data: URI %1",
     "args0": [
       {
@@ -268,7 +268,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "style": "text_blocks"
   },
   {
-    "type": "image_small",
+    "type": "test_images_small",
     "message0": "Image too small %1",
     "args0": [
       {
@@ -282,7 +282,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "style": "text_blocks"
   },
   {
-    "type": "image_large",
+    "type": "test_images_large",
     "message0": "Image too large %1",
     "args0": [
       {
@@ -296,7 +296,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "style": "text_blocks"
   },
   {
-    "type": "image_fliprtl",
+    "type": "test_images_fliprtl",
     "message0": "Image flipped RTL %1",
     "args0": [
       {
@@ -311,7 +311,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "colour": 160
   },
   {
-    "type": "image_missing",
+    "type": "test_images_missing",
     "message0": "Image missing %1",
     "args0": [
       {
@@ -325,7 +325,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "style": "text_blocks"
   },
   {
-    "type": "test_with_lots_of_network_icons",
+    "type": "test_images_many_icons",
     "message0": "Lots of network icons: %1 %2 %3 %4 %5 %6 %7 %8 %9 %10 %11 %12 %13 %14 %15 %16 %17 %18",
     "args0": [
       {
@@ -450,13 +450,13 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "style": "text_blocks"
   },
   {
-    "type": "styled_event_cap",
+    "type": "test_style_hat",
     "message0": "Hat block (event)",
     "nextStatement": null,
     "style": "hat_blocks"
   },
   {
-    "type": "block_colour_hex1",
+    "type": "test_style_hex1",
     "message0": "Block color: Bright purple %1 %2 %3 %4",
     "args0": [
       {
@@ -487,7 +487,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "colour": "#992aff"
   },
   {
-    "type": "block_colour_hex2",
+    "type": "test_style_hex2",
     "message0": "Block color: White %1 %2 %3 %4",
     "args0": [
       {
@@ -518,7 +518,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "colour": "#fefefe"
   },
   {
-    "type": "block_colour_hex3",
+    "type": "test_style_hex3",
     "message0": "Block color: Black %1 %2 %3 %4",
     "args0": [
       {
@@ -549,33 +549,33 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "colour": "#010101"
   },
   {
-    "type": "block_no_colour",
+    "type": "test_style_no_colour",
     "message0": "Block color: unset"
   },
   {
-    "type": "block_colour_hex4",
+    "type": "test_style_hex4",
     "message0": "Block color: #RRGGBBAA (invalid)",
     "colour": "#992aff99"
   },
   {
-    "type": "block_colour_hex5",
+    "type": "test_style_hex5",
     "message0": "Block color: #RRGGBB (invalid)",
     "colour": "#NotHex"
   },
   {
-    "type": "emoji_label_robot_face",
+    "type": "test_style_emoji",
     "message0": "Robot Face: \uD83E\uDD16",
     "colour": "#AAAAAA"
   }
 ]);  // END JSON EXTRACT (Do not delete this comment.)
 
-Blockly.Blocks['empty_block_with_mutator'] = {
+Blockly.Blocks['test_basic_empty_with_mutator'] = {
   init: function() {
     this.setMutator(new Blockly.Mutator(['math_number']));
   }
 };
 
-Blockly.Blocks['test_dropdown_dynamic'] = {
+Blockly.Blocks['test_fields_dropdown_dynamic'] = {
   init: function() {
     var dropdown = new Blockly.FieldDropdown(this.dynamicOptions);
     this.appendDummyInput()
diff --git a/tests/playground.html b/tests/playground.html
index 66d4e935c..e961c49e5 100644
--- a/tests/playground.html
+++ b/tests/playground.html
@@ -104,7 +104,7 @@ function start() {
           },
         horizontalLayout: side == 'top' || side == 'bottom',
         maxBlocks: Infinity,
-        maxInstances: {'limit_instances': 3},
+        maxInstances: {'test_basic_limit_instances': 3},
         media: '../media/',
         oneBasedIndex: true,
         readOnly: false,
@@ -1105,11 +1105,11 @@ h1 {
   code paths. -->
   <xml id="toolbox-test-blocks" style="display: none">
     <category name="Basic">
-      <block type="empty_block"></block>
-      <block type="empty_block_with_mutator"></block>
-      <block type="value_to_stack"></block>
-      <block type="value_to_statement"></block>
-      <block type="limit_instances"></block>
+      <block type="test_basic_empty"></block>
+      <block type="test_basic_empty_with_mutator"></block>
+      <block type="test_basic_value_to_stack"></block>
+      <block type="test_basic_value_to_statement"></block>
+      <block type="test_basic_limit_instances"></block>
     </category>
     <category name="Drag">
       <label text="Drag each to the workspace"></label>
@@ -1194,29 +1194,29 @@ h1 {
     </category>
     <category name="Fields">
       <label text="Numbers"></label>
-      <block type="test_number">
+      <block type="test_fields_number">
         <field name="NUM">123.456</field>
       </block>
-      <block type="test_integer">
+      <block type="test_fields_integer">
         <field name="NUM">123.456</field>
       </block>
-      <block type="test_number_hundredths">
+      <block type="test_fields_number_hundredths">
         <field name="NUM">123.456</field>
       </block>
-      <block type="test_integer_bounded">
+      <block type="test_fields_integer_bounded">
         <field name="NOTE">60</field>
       </block>
       <label text="Drop-downs"></label>
-      <block type="example_dropdown_long"></block>
-      <block type="example_dropdown_images"></block>
-      <block type="example_dropdown_images_and_text"></block>
+      <block type="test_fields_dropdown_long"></block>
+      <block type="test_fields_dropdown_images"></block>
+      <block type="test_fields_dropdown_images_and_text"></block>
       <label text="Dynamic Drop-downs"></label>
-      <block type="test_dropdown_dynamic"></block>
+      <block type="test_fields_dropdown_dynamic"></block>
       <button text="Add option" callbackKey="addDynamicOption"></button>
       <button text="Remove option" callbackKey="removeDynamicOption"></button>
       <label text="Others"></label>
-      <block type="example_angle"></block>
-      <block type="example_date"></block>
+      <block type="test_fields_angle"></block>
+      <block type="test_fields_date"></block>
     </category>
     <category name="Mutators">
       <label text="logic_compare"></label>
@@ -1247,24 +1247,24 @@ h1 {
     </category>
     <category name="Style">
       <label text="Hats"></label>
-      <block type="styled_event_cap"></block>
+      <block type="test_style_hat"></block>
       <label text="Colour"></label>
-      <block type="block_colour_hex1"></block>
-      <block type="block_colour_hex2"></block>
-      <block type="block_colour_hex3"></block>
-      <block type="block_no_colour"></block>
-      <block type="block_colour_hex4"></block>
-      <block type="block_colour_hex5"></block>
+      <block type="test_style_hex1"></block>
+      <block type="test_style_hex2"></block>
+      <block type="test_style_hex3"></block>
+      <block type="test_style_no_colour"></block>
+      <block type="test_style_hex4"></block>
+      <block type="test_style_hex5"></block>
     </category>
     <category name="Images">
-      <block type="image_datauri"></block>
-      <block type="image_small"></block>
-      <block type="image_large"></block>
-      <block type="image_fliprtl"></block>
-      <block type="image_missing"></block>
-      <block type="test_with_lots_of_network_icons"></block>
+      <block type="test_images_datauri"></block>
+      <block type="test_images_small"></block>
+      <block type="test_images_large"></block>
+      <block type="test_images_fliprtl"></block>
+      <block type="test_images_missing"></block>
+      <block type="test_images_many_icons"></block>
       <label text="Unicode & Emojis"></label>
-      <block type="emoji_label_robot_face"></block>
+      <block type="test_style_emoji"></block>
       <block type="text">
         <field name="TEXT">Robot face in text field: &#x1f916;</field>
       </block>