diff --git a/src/wp-includes/export/class-wp-export-query.php b/src/wp-includes/export/class-wp-export-query.php
index d0948da..30de3fe 100644
--- a/src/wp-includes/export/class-wp-export-query.php
+++ b/src/wp-includes/export/class-wp-export-query.php
@@ -72,7 +72,7 @@ class WP_Export_Query {
 
 	public function categories() {
 		if ( $this->category ) {
-			return $this->category;
+			return array( $this->category );
 		}
 		if ( $this->filters['post_type'] ) {
 			return array();
diff --git a/tests/phpunit/tests/export/class-wp-export-query.php b/tests/phpunit/tests/export/class-wp-export-query.php
index 0fd90d6..5be2567 100644
--- a/tests/phpunit/tests/export/class-wp-export-query.php
+++ b/tests/phpunit/tests/export/class-wp-export-query.php
@@ -174,7 +174,9 @@ class Test_WP_Export_Query extends WP_UnitTestCase {
 		$category_id = $this->factory->category->create( array( 'name' => 'baba' ) );
 		$other_category_id = $this->factory->category->create( array( 'name' => 'dyado' ) );
 		$export = new WP_Export_Query( array( 'post_type' => 'post', 'category' => $category_id ) );
-		$this->assertEquals( 1, count( $export->categories() ) );
+		$categories = $export->categories();
+		$this->assertTrue( is_array( $categories ) );
+		$this->assertEquals( 1, count( $categories ) );
 	}
 
 	function test_categories_should_return_no_categories_if_we_are_requesting_only_one_post_type() {