yarn add @blockly/block-test

npm install @blockly/block-test --save

import * as Blockly from 'blockly';
import {toolboxTestBlocks, toolboxTestBlocksInit} from '@blockly/block-test';

// Configure the Blockly workspace to use the test block's toolbox.
const workspace = Blockly.inject('blocklyDiv', {
  ...options
  toolbox: toolboxTestBlocks,
});

// Initalize the test block's toolbox.
toolboxTestBlocksInit(workspace);