diff --git tests/phpunit/tests/date/dateI18n.php tests/phpunit/tests/date/dateI18n.php
index 5a13e3c437..1bd541bfeb 100644
--- tests/phpunit/tests/date/dateI18n.php
+++ tests/phpunit/tests/date/dateI18n.php
@@ -19,6 +19,11 @@ class Tests_Date_I18n extends WP_UnitTestCase {
 		$this->assertEquals( $wp_timestamp, date_i18n( 'U', 'invalid' ), '', 5 );
 	}
 
+	public function test_should_return_epoch_start_on_0() {
+		$this->assertEquals( 0, date_i18n( 'U', 0 ) );
+		$this->assertEquals( '1970-01-01', date_i18n( 'Y-m-d', 0 ) );
+	}
+
 	public function test_should_format_date() {
 		$this->assertEquals( strtotime( gmdate( 'Y-m-d H:i:s' ) ), strtotime( date_i18n( 'Y-m-d H:i:s' ) ), 'The dates should be equal', 2 );
 	}