diff --git a/index.php b/index.php
index 03c4de6f16f94..6d7adaf579de2 100644
--- a/index.php
+++ b/index.php
@@ -33,10 +33,10 @@ function gutenberg_menu() {
 /**
  * Registers a block.
  *
- * @param  string   $slug     Block slug including namespace.
- * @param  array    $settings Block settings
+ * @param  string $slug Block slug including namespace.
+ * @param  array  $settings Block settings.
 
- * @return array              The block, if it has been successfully registered.
+ * @return array            The block, if it has been successfully registered.
  */
 function register_block( $slug, $settings ) {
 	global $registered_blocks;
@@ -58,7 +58,7 @@ function register_block( $slug, $settings ) {
 		return;
 	}
 
-	$settings[ 'slug' ] = $slug;
+	$settings['slug'] = $slug;
 	$registered_blocks[ $slug ] = $settings;
 
 	return $settings;
@@ -67,13 +67,14 @@ function register_block( $slug, $settings ) {
 /**
  * Unregisters a block.
  *
- * @param  string   slug Block slug
- * @return array         The previous block value, if it has been
- *                         successfully unregistered; otherwise `null`.
+ * @param  string $slug Block slug.
+ * @return array        The previous block value, if it has been
+ *                        successfully unregistered; otherwise `null`.
  */
 function unregister_block( $slug ) {
 	global $registered_blocks;
 	if ( ! isset( $registered_blocks[ $slug ] ) ) {
+		/* translators: 1: block slug */
 		$message = sprintf( __( 'Block "%s" is not registered.' ), $slug );
 		_doing_it_wrong( __FUNCTION__, $message, '0.1.0' );
 		return;
@@ -86,7 +87,7 @@ function unregister_block( $slug ) {
  *
  * @since 0.1.0
  *
- * @param  string $attr_string Attributes string
+ * @param string $attr_string Attributes string.
 
  * @return array
  */
@@ -94,8 +95,8 @@ function parse_block_attributes( $attr_string ) {
 	$attributes_matcher = '/([^\s]+):([^\s]+)\s*/';
 	preg_match_all( $attributes_matcher, $attr_string, $matches );
 	$attributes = array();
-	foreach ( $matches[ 1 ] as $index => $attribute_match ) {
-		$attributes[ $attribute_match ] = $matches[ 2 ][ $index ];
+	foreach ( $matches[1] as $index => $attribute_match ) {
+		$attributes[ $attribute_match ] = $matches[2][ $index ];
 	}
 
 	return $attributes;
@@ -106,40 +107,40 @@ function parse_block_attributes( $attr_string ) {
  *
  * @since 0.1.0
  *
- * @param  string $content Post content
-
- * @return string          Updated post content
+ * @param  string $content Post content.
+ *
+ * @return string          Updated post content.
  */
 function do_blocks( $content ) {
 	global $registered_blocks;
 
-	// Extract the blocks from the post content
+	// Extract the blocks from the post content.
 	$open_matcher = '/<!--\s*wp:([a-z](?:[a-z0-9\/]+)*)\s+((?:(?!-->).)*)-->.*?<!--\s*\/wp:\g1\s+-->/';
 	preg_match_all( $open_matcher, $content, $matches, PREG_OFFSET_CAPTURE );
 
 	$new_content = $content;
-	foreach ( $matches[ 0 ] as $index => $block_match ) {
-		$block_name = $matches[ 1 ][ $index ][ 0 ];
-		// do nothing if the block is not registered
+	foreach ( $matches[0] as $index => $block_match ) {
+		$block_name = $matches[1][ $index ][0];
+		// do nothing if the block is not registered.
 		if ( ! isset( $registered_blocks[ $block_name ] ) ) {
 			continue;
 		}
 
-		$block_markup = $block_match[ 0 ];
-		$block_position = $block_match[ 1 ];
-		$block_attributes_string = $matches[ 2 ][ $index ][ 0 ];
+		$block_markup = $block_match[0];
+		$block_position = $block_match[1];
+		$block_attributes_string = $matches[2][ $index ][0];
 		$block_attributes = parse_block_attributes( $block_attributes_string );
 
-		// Call the block's render function to generate the dynamic output
-		$output = call_user_func( $registered_blocks[ $block_name ][ 'render' ], $block_attributes );
+		// Call the block's render function to generate the dynamic output.
+		$output = call_user_func( $registered_blocks[ $block_name ]['render'], $block_attributes );
 
-		// Replace the matched block with the dynamic output
+		// Replace the matched block with the dynamic output.
 		$new_content = str_replace( $block_markup, $output, $new_content );
 	}
 
 	return $new_content;
 }
-add_filter( 'the_content', 'do_blocks', 10 ); // BEFORE do_shortcode()
+add_filter( 'the_content', 'do_blocks', 10 ); // BEFORE do_shortcode().
 
 /**
  * Registers common scripts to be used as dependencies of the editor and plugins.
@@ -173,9 +174,9 @@ function gutenberg_register_scripts() {
  * @since 0.1.0
  */
 function gutenberg_add_edit_links_filters() {
-	// For hierarchical post types
+	// For hierarchical post types.
 	add_filter( 'page_row_actions', 'gutenberg_add_edit_links', 10, 2 );
-	// For non-hierarchical post types
+	// For non-hierarchical post types.
 	add_filter( 'post_row_actions', 'gutenberg_add_edit_links', 10, 2 );
 }
 add_action( 'admin_init', 'gutenberg_add_edit_links_filters' );
@@ -185,14 +186,18 @@ function gutenberg_add_edit_links_filters() {
  * the Gutenberg editor.
  *
  * @since 0.1.0
+ *
+ * @param  array $actions Post actions.
+ * @param  array $post    Edited post.
+ *
+ * @return array          Updated post actions.
  */
 function gutenberg_add_edit_links( $actions, $post ) {
 	$can_edit_post = current_user_can( 'edit_post', $post->ID );
 	$title = _draft_or_post_title( $post->ID );
 
 	if ( $can_edit_post && 'trash' !== $post->post_status ) {
-		// Build the Gutenberg edit action.  See also:
-		// WP_Posts_List_Table::handle_row_actions()
+		// Build the Gutenberg edit action. See also: WP_Posts_List_Table::handle_row_actions().
 		$gutenberg_url = menu_page_url( 'gutenberg', false );
 		$gutenberg_action = sprintf(
 			'<a href="%s" aria-label="%s">%s</a>',
@@ -208,7 +213,9 @@ function gutenberg_add_edit_links( $actions, $post ) {
 		$edit_offset = array_search( 'edit', array_keys( $actions ), true );
 		$actions = array_merge(
 			array_slice( $actions, 0, $edit_offset + 1 ),
-			array( 'gutenberg hide-if-no-js' => $gutenberg_action ),
+			array(
+				'gutenberg hide-if-no-js' => $gutenberg_action,
+			),
 			array_slice( $actions, $edit_offset + 1 )
 		);
 	}
@@ -221,6 +228,8 @@ function gutenberg_add_edit_links( $actions, $post ) {
  *
  * @since 0.1.0
  *
+ * @param  string $domain Translation domain.
+ *
  * @return array
  */
 function gutenberg_get_jed_locale_data( $domain ) {
@@ -232,10 +241,10 @@ function gutenberg_get_jed_locale_data( $domain ) {
 			$domain => array(
 				'' => array(
 					'domain' => $domain,
-					'lang'   => is_admin() ? get_user_locale() : get_locale()
-				)
-			)
-		)
+					'lang'   => is_admin() ? get_user_locale() : get_locale(),
+				),
+			),
+		),
 	);
 
 	if ( ! empty( $translations->headers['Plural-Forms'] ) ) {
@@ -268,16 +277,16 @@ function gutenberg_scripts_and_styles( $hook ) {
 	 * Scripts
 	 */
 
-	// The editor code itself
+	// The editor code itself.
 	wp_enqueue_script(
 		'wp-editor',
 		plugins_url( 'editor/build/index.js', __FILE__ ),
 		array( 'wp-i18n', 'wp-blocks', 'wp-element' ),
 		filemtime( plugin_dir_path( __FILE__ ) . 'editor/build/index.js' ),
-		true   // $in_footer
+		true // enqueue in the footer.
 	);
 
-	// Load an actual post if an ID is specified
+	// Load an actual post if an ID is specified.
 	$post_to_edit = null;
 	if ( isset( $_GET['post_id'] ) && (int) $_GET['post_id'] > 0 ) {
 		$request = new WP_REST_Request(
@@ -304,7 +313,7 @@ function gutenberg_scripts_and_styles( $hook ) {
 		);
 	}
 
-	// Prepare Jed locale data
+	// Prepare Jed locale data.
 	$locale_data = gutenberg_get_jed_locale_data( 'gutenberg' );
 	wp_add_inline_script(
 		'wp-editor',
@@ -312,7 +321,7 @@ function gutenberg_scripts_and_styles( $hook ) {
 		'before'
 	);
 
-	// Initialize the editor
+	// Initialize the editor.
 	wp_add_inline_script( 'wp-editor', 'wp.editor.createEditorInstance( \'editor\', _wpGutenbergPost );' );
 
 	/**
@@ -361,11 +370,3 @@ function the_gutenberg_project() {
 	</div>
 	<?php
 }
-
-function render_html_block( $attributes ) {
-	return 'THIS IS AWESOME';
-}
-
-register_block( 'core/html', array(
-	'render' => 'render_html_block'
-) );
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index ed4079d33ed58..2eb5f4eae3c4b 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -8,7 +8,7 @@
 	>
 	<testsuites>
 		<testsuite>
-			<directory prefix="test-" suffix=".php">./phpunit/</directory>
+			<directory suffix="-test.php">./phpunit/</directory>
 		</testsuite>
 	</testsuites>
 </phpunit>
diff --git a/phpunit/test-dynamic-blocks-render.php b/phpunit/class-dynamic-blocks-render-test.php
similarity index 54%
rename from phpunit/test-dynamic-blocks-render.php
rename to phpunit/class-dynamic-blocks-render-test.php
index eadeaf97e7eb7..a7c01439ccf2d 100644
--- a/phpunit/test-dynamic-blocks-render.php
+++ b/phpunit/class-dynamic-blocks-render-test.php
@@ -1,26 +1,35 @@
 <?php
+/**
+ * Dynamic blocks rendering Test
+ *
+ * @package Gutenberg
+ */
 
-class DynamicBlocksRenderTest extends WP_UnitTestCase {
+/**
+ * Test do_blocks
+ */
+class Dynamic_Blocks_Render_Test extends WP_UnitTestCase {
 	/**
-	 * @expectedIncorrectUsage register_block
+	 * Dummy block rendering function.
+	 *
+	 * @param  array $attributes Block attributes.
+	 *
+	 * @return string             Block output.
 	 */
-	function test_invalid_non_string_slugs() {
-		register_block( 1, array() );
+	function render_dummy_block( $attributes ) {
+		return $attributes['value'];
 	}
 
 	/**
-	 * @expectedIncorrectUsage register_block
+	 * Successfull dynamic block rendering
 	 */
-	function test_invalid_slugs_without_namespace() {
-		register_block( 'text', array() );
-	}
-
-	function render_dummy_block( $attributes ) {
-		return $attributes[ 'value' ];
-	}
-
 	function test_register_block() {
-		$settings = array( 'render' => [ $this, 'render_dummy_block' ] );
+		$settings = array(
+			'render' => array(
+				$this,
+				'render_dummy_block',
+			),
+		);
 		register_block( 'core/dummy', $settings );
 		$post_content =
 			'before' .
diff --git a/phpunit/test-registration.php b/phpunit/class-registration-test.php
similarity index 58%
rename from phpunit/test-registration.php
rename to phpunit/class-registration-test.php
index e18ee72e34817..08b86e58fe394 100644
--- a/phpunit/test-registration.php
+++ b/phpunit/class-registration-test.php
@@ -1,7 +1,17 @@
 <?php
+/**
+ * Blocks registration Tests
+ *
+ * @package Gutenberg
+ */
 
-class RegistrationTest extends WP_UnitTestCase {
+/**
+ * Test register_block
+ */
+class Registration_Test extends WP_UnitTestCase {
 	/**
+	 * The block slug should be a string
+	 *
 	 * @expectedIncorrectUsage register_block
 	 */
 	function test_invalid_non_string_slugs() {
@@ -9,18 +19,25 @@ function test_invalid_non_string_slugs() {
 	}
 
 	/**
+	 * The block slug should have a namespace
+	 *
 	 * @expectedIncorrectUsage register_block
 	 */
 	function test_invalid_slugs_without_namespace() {
 		register_block( 'text', array() );
 	}
 
+	/**
+	 * Successfull block registration
+	 */
 	function test_register_block() {
-		$settings = array( 'icon' => 'text' );
+		$settings = array(
+			'icon' => 'text',
+		);
 		$updated_settings = register_block( 'core/text', $settings );
 		$this->assertEquals( $updated_settings, array(
 			'icon' => 'text',
-			'slug' => 'core/text'
+			'slug' => 'core/text',
 		) );
 		unregister_block( 'core/text' );
 	}