diff --git a/src/wp-includes/blocks.php b/src/wp-includes/blocks.php
index b04696d591..2ec3a07e3e 100644
--- a/src/wp-includes/blocks.php
+++ b/src/wp-includes/blocks.php
@@ -7,6 +7,39 @@
  * @since 5.0.0
  */
 
+/**
+ * Registers a block type.
+ *
+ * @since 5.0.0
+ *
+ * @param string|WP_Block_Type $name Block type name including namespace, or alternatively a
+ *                                   complete WP_Block_Type instance. In case a WP_Block_Type
+ *                                   is provided, the $args parameter will be ignored.
+ * @param array                $args {
+ *     Optional. Array of block type arguments. Any arguments may be defined, however the
+ *     ones described below are supported by default. Default empty array.
+ *
+ *     @type callable $render_callback Callback used to render blocks of this block type.
+ * }
+ * @return WP_Block_Type|false The registered block type on success, or false on failure.
+ */
+function register_block_type( $name, $args = array() ) {
+	return WP_Block_Type_Registry::get_instance()->register( $name, $args );
+}
+
+/**
+ * Unregisters a block type.
+ *
+ * @since 5.0.0
+ *
+ * @param string|WP_Block_Type $name Block type name including namespace, or alternatively a
+ *                                   complete WP_Block_Type instance.
+ * @return WP_Block_Type|false The unregistered block type on success, or false on failure.
+ */
+function unregister_block_type( $name ) {
+	return WP_Block_Type_Registry::get_instance()->unregister( $name );
+}
+
 /**
  * Determine whether a post or content string has blocks.
  *
@@ -59,3 +92,23 @@ function has_block( $block_type, $post = null ) {
 
 	return false !== strpos( $post, '<!-- wp:' . $block_type . ' ' );
 }
+
+/**
+ * Returns an array of the names of all registered dynamic block types.
+ *
+ * @since 5.0.0
+ *
+ * @return array Array of dynamic block names.
+ */
+function get_dynamic_block_names() {
+	$dynamic_block_names = array();
+
+	$block_types = WP_Block_Type_Registry::get_instance()->get_all_registered();
+	foreach ( $block_types as $block_type ) {
+		if ( $block_type->is_dynamic() ) {
+			$dynamic_block_names[] = $block_type->name;
+		}
+	}
+
+	return $dynamic_block_names;
+}
diff --git a/tests/phpunit/data/blocks/do-blocks-expected.html b/tests/phpunit/data/blocks/do-blocks-expected.html
new file mode 100644
index 0000000000..4a3dc379ef
--- /dev/null
+++ b/tests/phpunit/data/blocks/do-blocks-expected.html
@@ -0,0 +1,17 @@
+<p>First Auto Paragraph</p>
+
+<!--more-->
+
+<p>First Gutenberg Paragraph</p>
+
+<p>Second Auto Paragraph</p>
+
+
+<p>Third Gutenberg Paragraph</p>
+
+<p>Third Auto Paragraph</p>
+
+<p>[someshortcode]</p>
+<p>And some content?!</p>
+<p>[/someshortcode]</p>
+
diff --git a/tests/phpunit/data/blocks/do-blocks-original.html b/tests/phpunit/data/blocks/do-blocks-original.html
new file mode 100644
index 0000000000..bbd2eb4bb1
--- /dev/null
+++ b/tests/phpunit/data/blocks/do-blocks-original.html
@@ -0,0 +1,25 @@
+<p>First Auto Paragraph</p>
+
+<!--more-->
+
+<!-- wp:core/paragraph -->
+<p>First Gutenberg Paragraph</p>
+<!-- /wp:core/paragraph -->
+
+<p>Second Auto Paragraph</p>
+
+<!-- wp:core/test-self-closing /-->
+
+<!-- wp:core/paragraph -->
+<p>Third Gutenberg Paragraph</p>
+<!-- /wp:core/paragraph -->
+
+<p>Third Auto Paragraph</p>
+
+<!-- wp:core/shortcode -->
+[someshortcode]
+
+And some content?!
+
+[/someshortcode]
+<!-- /wp:core/shortcode -->
diff --git a/tests/phpunit/tests/blocks/register.php b/tests/phpunit/tests/blocks/register.php
new file mode 100644
index 0000000000..8271c9babd
--- /dev/null
+++ b/tests/phpunit/tests/blocks/register.php
@@ -0,0 +1,141 @@
+<?php
+/**
+ * Block registry tests.
+ *
+ * @package WordPress
+ * @subpackage Blocks
+ * @since 5.0.0
+ */
+
+/**
+ * Tests for register_block_type(), unregister_block_type(), get_dynamic_block_names()
+ *
+ * @since 5.0.0
+ *
+ * @group blocks
+ */
+class WP_Test_Block_Register extends WP_UnitTestCase {
+
+	/**
+	 * ID for a test post.
+	 *
+	 * @since 5.0.0
+	 * @var int
+	 */
+	protected static $post_id;
+
+	/**
+	 * Set up before class.
+	 *
+	 * @since 5.0.0
+	 */
+	public static function wpSetUpBeforeClass( $factory ) {
+		self::$post_id = $factory->post->create(
+			array(
+				'post_content' => file_get_contents( DIR_TESTDATA . '/blocks/do-blocks-original.html' ),
+			)
+		);
+	}
+
+	/**
+	 * Tear down after class.
+	 *
+	 * @since 5.0.0
+	 */
+	public static function wpTearDownAfterClass() {
+		// Also deletes revisions.
+		wp_delete_post( self::$post_id, true );
+	}
+
+	/**
+	 * Empty render function for tests to use.
+	 */
+	function render_stub() {}
+
+	/**
+	 * Tear down after each test.
+	 *
+	 * @since 5.0.0
+	 */
+	function tearDown() {
+		parent::tearDown();
+
+		$registry = WP_Block_Type_Registry::get_instance();
+
+		foreach ( array( 'test-static', 'test-dynamic' ) as $block_name ) {
+			$block_name = 'core/' . $block_name;
+
+			if ( $registry->is_registered( $block_name ) ) {
+				$registry->unregister( $block_name );
+			}
+		}
+	}
+
+	/**
+	 * @ticket 45109
+	 */
+	function test_register_affects_main_registry() {
+		$name     = 'core/test-static';
+		$settings = array(
+			'icon' => 'text',
+		);
+
+		register_block_type( $name, $settings );
+
+		$registry = WP_Block_Type_Registry::get_instance();
+		$this->assertTrue( $registry->is_registered( $name ) );
+	}
+
+	/**
+	 * @ticket 45109
+	 */
+	function test_unregister_affects_main_registry() {
+		$name     = 'core/test-static';
+		$settings = array(
+			'icon' => 'text',
+		);
+
+		register_block_type( $name, $settings );
+		unregister_block_type( $name );
+
+		$registry = WP_Block_Type_Registry::get_instance();
+		$this->assertFalse( $registry->is_registered( $name ) );
+	}
+
+	/**
+	 * @ticket 45109
+	 */
+	function test_get_dynamic_block_names() {
+		register_block_type( 'core/test-static', array() );
+		register_block_type( 'core/test-dynamic', array( 'render_callback' => array( $this, 'render_stub' ) ) );
+
+		$dynamic_block_names = get_dynamic_block_names();
+
+		$this->assertContains( 'core/test-dynamic', $dynamic_block_names );
+		$this->assertNotContains( 'core/test-static', $dynamic_block_names );
+	}
+
+	/**
+	 * @ticket 45109
+	 */
+	function test_has_blocks() {
+		// Test with passing post ID.
+		$this->assertTrue( has_blocks( self::$post_id ) );
+
+		// Test with passing WP_Post object.
+		$this->assertTrue( has_blocks( get_post( self::$post_id ) ) );
+
+		// Test with passing content string.
+		$this->assertTrue( has_blocks( get_post( self::$post_id ) ) );
+
+		// Test default.
+		$this->assertFalse( has_blocks() );
+		$query = new WP_Query( array( 'post__in' => array( self::$post_id ) ) );
+		$query->the_post();
+		$this->assertTrue( has_blocks() );
+
+		// Test string (without blocks).
+		$content = file_get_contents( DIR_TESTDATA . '/blocks/do-blocks-expected.html' );
+		$this->assertFalse( has_blocks( $content ) );
+	}
+}