Tests: Add unit tests for a label fallback in WP_Block_Styles_Registry::register().

Follow-up to [59760].

Props Rahmohn, mukesh27, SergeyBiryukov.
See #63167.

git-svn-id: https://develop.svn.wordpress.org/trunk@61186 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

tests/phpunit/tests/blocks/wpBlockStylesRegistry.php

@@ -7,6 +7,7 @@
  * @since 6.6.0
  *
  * @group blocks
+ * @coversDefaultClass WP_Block_Styles_Registry
  */
 class Tests_Blocks_wpBlockStylesRegistry extends WP_UnitTestCase {
 
@@ -67,6 +68,63 @@ public function test_register_block_style_with_array_of_block_names() {
 		$this->assertTrue( $this->registry->is_registered( 'core/group', 'plain' ) );
 	}
 
+	/**
+	 * Should accept valid string style label. The registered style should have the same label.
+	 *
+	 * @ticket 52592
+	 *
+	 * @covers ::register
+	 * @covers ::is_registered
+	 * @covers ::get_registered_styles_for_block
+	 */
+	public function test_register_block_style_with_label() {
+		$name             = 'core/paragraph';
+		$style_properties = array(
+			'name'  => 'fancy',
+			'label' => 'Fancy',
+		);
+		$result           = $this->registry->register( $name, $style_properties );
+
+		$this->assertTrue( $result, 'The block style should be registered when the label is a valid string.' );
+		$this->assertTrue(
+			$this->registry->is_registered( $name, 'fancy' ),
+			'The block type should have the block style registered when the label is valid.'
+		);
+		$this->assertSame(
+			$style_properties['label'],
+			$this->registry->get_registered_styles_for_block( $name )['fancy']['label'],
+			'The registered block style should have the same label.'
+		);
+	}
+
+	/**
+	 * Should register the block style when `label` is missing, using `name` as the label.
+	 *
+	 * @ticket 52592
+	 *
+	 * @covers ::register
+	 * @covers ::is_registered
+	 * @covers ::get_registered_styles_for_block
+	 */
+	public function test_register_block_style_without_label() {
+		$name             = 'core/paragraph';
+		$style_properties = array(
+			'name' => 'fancy',
+		);
+		$result           = $this->registry->register( $name, $style_properties );
+
+		$this->assertTrue( $result, 'The block style should be registered when the label is missing.' );
+		$this->assertTrue(
+			$this->registry->is_registered( $name, 'fancy' ),
+			'The block type should have the block style registered when the label is missing.'
+		);
+		$this->assertSame(
+			$style_properties['name'],
+			$this->registry->get_registered_styles_for_block( $name )['fancy']['label'],
+			'The registered block style label should be the same as the name.'
+		);
+	}
+
 	/**
 	 * @ticket 63957
 	 */