Ticket #25706: 25706.diff

src/wp-includes/category-template.php

@@ -232 +232 @@
  * @return bool True if the current post is in any of the given categories.
  */
 function in_category( $category, $post = null ) {
+        if ( empty( $category ) )
+                return false;
+
         return has_category( $category, $post );
 }
 

tests/phpunit/tests/taxonomy.php

@@ -152 +152 @@
                 _unregister_post_type( $post_type );
 
         }
+        /**
+         * @ticket 25706
+         */
+        function test_in_category() {
+                $post = $this->factory->post->create_and_get();
+
+                // in_category() returns false when first parameter is empty()
+                $this->assertFalse( in_category( '', $post ) );
+                $this->assertFalse( in_category( false, $post ) );
+                $this->assertFalse( in_category( null, $post ) );
+
+                // Test expected behavior of in_category()
+                $term = wp_insert_term( 'Test', 'category' );
+                wp_set_object_terms( $post->ID, $term['term_id'], 'category' );
+                $this->assertTrue( in_category( $term['term_id'], $post ) );
+        }
 }