Add basic PHPUnit tests for block metadata registration

lib/compat.php

@@ -8,15 +8,13 @@
  * @package gutenberg
  */
 
- if ( ! function_exists( 'register_block_type_from_metadata' ) ) {
+if ( ! function_exists( 'register_block_type_from_metadata' ) ) {
 	/**
 	 * Registers a block type from metadata stored in the `block.json` file.
 	 *
 	 * @since 7.8.0
 	 *
 	 * @param string $path Path to the folder where the `block.json` file is located.
-	 *                     Alternatively it's possible to provide only the name of the
-	 *                     last folder for blocks located in the WordPress core.
 	 * @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.
@@ -26,13 +24,12 @@
 	 * @return WP_Block_Type|false The registered block type on success, or false on failure.
 	 */
 	function register_block_type_from_metadata( $path, $args = array() ) {
-		$path = is_dir( $path ) ? $path : ABSPATH . WPINC . '/blocks/' . $path;
 		$file = trailingslashit( $path ) . 'block.json';
 		if ( ! file_exists( $file ) ) {
 			return false;
 		}
 
-		$metadata = json_decode( file_get_contents( $path ), true );
+		$metadata = json_decode( file_get_contents( $file ), true );
 		if ( ! is_array( $metadata ) ) {
 			return false;
 		}
@@ -45,7 +42,7 @@ function register_block_type_from_metadata( $path, $args = array() ) {
 			)
 		);
 	}
- }
+}
 
 /**
  * Adds a polyfill for the WHATWG URL in environments which do not support it.

phpunit/class-register-block-type-from-metadata-test.php

@@ -0,0 +1,45 @@
+<?php
+/**
+ * Test `register_block_type_from_metadata`.
+ *
+ * @package Gutenberg
+ */
+
+class Register_Block_Type_From_Metadata_Test extends WP_UnitTestCase {
+	/**
+	 * Tests that the function returns false when the `block.json` is not found
+	 * in the WordPress core.
+	 */
+	function test_metadata_not_found_in_wordpress_core() {
+		$result = register_block_type_from_metadata( 'unknown' );
+
+		$this->assertFalse( $result );
+	}
+
+	/**
+	 * Tests that the function returns false when the `block.json` is not found
+	 * in the current directory.
+	 */
+	function test_metadata_not_found_in_the_current_directory() {
+		$result = register_block_type_from_metadata( __DIR__ );
+
+		$this->assertFalse( $result );
+	}
+
+	/**
+	 * Tests that the function returns the registered block when the `block.json`
+	 * is found in the fixtures directory.
+	 */
+	function test_block_registers_with_metadata_fixture() {
+		$result = register_block_type_from_metadata(
+			__DIR__ . '/fixtures',
+			array(
+				'foo' => 'bar',
+			)
+		);
+
+		$this->assertInstanceOf( 'WP_Block_Type', $result );
+		$this->assertEquals( 'test/block-name', $result->name );
+		$this->assertEquals( 'bar', $result->foo );
+	}
+}

phpunit/fixtures/block.json

@@ -0,0 +1,4 @@
+{
+	"name": "test/block-name",
+	"category": "widgets"
+}