Add test to cover custom site list column.

tests/Integration/UI/NetworkAdminSitesListTest.php

@@ -0,0 +1,47 @@
+<?php
+/**
+ * UI Tests for the Network Admin Sites List.
+ *
+ * @package Parsely\Tests\UI
+ */
+
+declare(strict_types=1);
+
+namespace Parsely\Tests\Integration\UI;
+
+use Parsely\Tests\Integration\TestCase;
+
+/**
+ * UI Tests for the Network Admin Sites List.
+ */
+final class NetworkAdminSitesListTest extends TestCase {
+	/**
+	 * Skip all tests for non-multisite runs.
+	 * Set up an instance variable to hold a `WP_MS_Sites_List_Table` object.
+	 *
+	 * @return void
+	 */
+	protected function setUp(): void {
+		parent::setUp();
+
+		if ( ! is_multisite() ) {
+			self::markTestSkipped();
+		}
+
+		$this->table = _get_list_table( 'WP_MS_Sites_List_Table', array( 'screen' => 'ms-sites' ) );
+	}
+
+	/**
+	 * Make sure the custom column is included.
+	 *
+	 * @return void
+	 */
+	public function test_api_key_column_is_present(): void {
+		$columns = $this->table->get_columns();
+
+		// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_var_export
+		var_export( $columns );
+
+		self::assertArrayNotHasKey( 'parsely-api-key', $columns );
+	}
+}