How can I create static blocks via a module install script?

I was able to create the install script by simply inserting the data into the two tables which store the static block details.

It could get a bit messy if you are installing many blocks but on the small scale this seems to be fine:

<?php

namespace MyVendor\MyModule\Setup;

use Magento\Framework\Setup\InstallDataInterface; 
use Magento\Framework\Setup\ModuleContextInterface; 
use Magento\Framework\Setup\ModuleDataSetupInterface;

class InstallData implements InstallDataInterface
{
    const TABLE_CMS_BLOCK = 'cms_block';

    const TABLE_CMS_BLOCK_STORE = 'cms_block_store';

    const STORE_ID = 0;

    private $testBlockDetails = [
        'title' => 'Test Block',
        'identifier' => 'test-block',
        'content' => "<h1>This is a test block piece of content</h1>",
        'is_active' => true
    ];

    /**
     * @param ModuleDataSetupInterface $setup
     * @param ModuleContextInterface $context
     */
    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        $testBlockId = $this->createTestBlockEntry($setup);
        if ($testBlockId) {
            $this->createTestBlockStoreAssociation($setup, $testBlockId);
        }
    }

    /**
     * @param ModuleDataSetupInterface $setup
     * @return bool
     */
    private function createTestBlockEntry(ModuleDataSetupInterface $setup)
    {
        $setup->startSetup();

        $cmsBlockTable = $setup->getTable(self::TABLE_CMS_BLOCK);
        $connection = $setup->getConnection();
        $connection->insertForce($cmsBlockTable, $this->testBlockDetails);

        $setup->endSetup();

        return $this->getBlockId($connection, $cmsBlockTable);
    }

    /**
     * @param $connection
     * @param $cmsBlockTable
     * @return bool
     */
    private function getBlockId($connection, $cmsBlockTable)
    {
        $select = $connection->select()
            ->from(['o' => $cmsBlockTable])
            ->where('o.identifier=?', $this->testBlockDetails['identifier'])
            ->limit(1);

        $row = $connection->fetchRow($select);
        if ($row) {
            return $row['block_id'];
        }
        return false;
    }

    /**
     * @param ModuleDataSetupInterface $setup
     * @param $testBlockId
     */
    private function createTestBlockStoreAssociation(ModuleDataSetupInterface $setup, $testBlockId)
    {
        $setup->getConnection()->insertForce(
            $setup->getTable(self::TABLE_CMS_BLOCK_STORE), [
                'store_id' => self::STORE_ID,
                'block_id' => $testBlockId
            ]
        );
    }
}

Once installed you should have a test block added with the details of the $testBlockDetails property. Will need to look at splitting this out into more classes for multiple blocks.