Fix pagination issue with migrate wp authors CLI command.

inc/cli/class-migrate-command.php

@@ -128,7 +128,11 @@ public function wp_authors( $args, $assoc_args ) : void {
 			WP_CLI::line( sprintf( 'Processed %d posts, pausing for a breath...', $count ) );
 			sleep( 2 );
 
-			$paged++;
+			// A normal run, don't need to paginate due to NOT EXISTS tax query.
+			// But for dry run or when overwriting, need to increment paged.
+			if ( $dry_run || $overwrite ) {
+				$paged++;
+			}
 		} while ( count( $posts ) );
 
 		if ( true === $dry_run ) {

tests/phpunit/test-cli.php

@@ -0,0 +1,57 @@
+<?php
+/**
+ * Plugin CLI command tests.
+ *
+ * @package authorship
+ */
+
+declare( strict_types=1 );
+
+namespace Authorship\Tests;
+
+use Authorship\CLI;
+use const Authorship\POSTS_PARAM;
+use const Authorship\TAXONOMY;
+
+class TestCLI extends TestCase {
+	public function set_up() {
+		parent::set_up();
+		require_once dirname( __DIR__, 2 ) . '/inc/cli/namespace.php';
+		require_once dirname( __DIR__, 2 ) . '/inc/cli/class-migrate-command.php';
+		CLI\bootstrap();
+	}
+
+	public function testMigrateWpAuthorsPagination() : void {
+		$factory = self::factory()->post;
+		$posts = [];
+
+		for ( $i = 0; $i < 200; $i++ ) {
+			$posts[] = $factory->create_and_get( [
+				'post_author' => self::$users['admin']->ID,
+				POSTS_PARAM   => [
+					self::$users['editor']->ID,
+				],
+			] );
+		}
+
+		$paged_post = $posts[100]; // Any post from second page of results.
+		$authorship_authors = \Authorship\get_authors( $paged_post );
+
+		// Asset initial authorship authors set correctly.
+		$this->assertCount( 1, $authorship_authors );
+		$this->assertSame( self::$users['editor']->ID, $authorship_authors[0]->ID );
+
+		// Migrate, overwriting authorship data with WP Author data.
+		$command = new CLI\Migrate_Command;
+		$command->wp_authors( [], [
+			'dry-run' => false,
+			'overwrite' => true,
+			'post-type' => 'post', // Must set default value manually.
+		] );
+
+		// Verify author data migrated correctly.
+		$authorship_authors = \Authorship\get_authors( $paged_post->ID );
+		$this->assertCount( 1, $authorship_authors );
+		$this->assertSame( self::$users['admin']->ID, $authorship_authors[0]->ID );
+	}
+}