Improve leap seconds test in optional/format/date-time

Author: ChALkeR

tests/draft-future/optional/format/date-time.json

@@ -23,14 +23,24 @@
                 "data": "1990-12-31T15:59:50.123-08:00",
                 "valid": true
             },
+            {
+                "description": "a valid date-time with a leap second, UTC",
+                "data": "1998-12-31T23:59:60Z",
+                "valid": true
+            },
+            {
+                "description": "a valid date-time with a leap second, with minus offset",
+                "data": "1998-12-31T15:59:60.123-08:00",
+                "valid": true
+            },
             {
                 "description": "a invalid day in date-time string",
-                "data": "1990-02-31T15:59:60.123-08:00",
+                "data": "1990-02-31T15:59:59.123-08:00",
                 "valid": false
             },
             {
                 "description": "an invalid offset in date-time string",
-                "data": "1990-12-31T15:59:60-24:00",
+                "data": "1990-12-31T15:59:59-24:00",
                 "valid": false
             },
             {

tests/draft2019-09/optional/format/date-time.json

@@ -23,14 +23,24 @@
                 "data": "1990-12-31T15:59:50.123-08:00",
                 "valid": true
             },
+            {
+                "description": "a valid date-time with a leap second, UTC",
+                "data": "1998-12-31T23:59:60Z",
+                "valid": true
+            },
+            {
+                "description": "a valid date-time with a leap second, with minus offset",
+                "data": "1998-12-31T15:59:60.123-08:00",
+                "valid": true
+            },
             {
                 "description": "a invalid day in date-time string",
-                "data": "1990-02-31T15:59:60.123-08:00",
+                "data": "1990-02-31T15:59:59.123-08:00",
                 "valid": false
             },
             {
                 "description": "an invalid offset in date-time string",
-                "data": "1990-12-31T15:59:60-24:00",
+                "data": "1990-12-31T15:59:59-24:00",
                 "valid": false
             },
             {

tests/draft2020-12/optional/format/date-time.json

@@ -23,14 +23,24 @@
                 "data": "1990-12-31T15:59:50.123-08:00",
                 "valid": true
             },
+            {
+                "description": "a valid date-time with a leap second, UTC",
+                "data": "1998-12-31T23:59:60Z",
+                "valid": true
+            },
+            {
+                "description": "a valid date-time with a leap second, with minus offset",
+                "data": "1998-12-31T15:59:60.123-08:00",
+                "valid": true
+            },
             {
                 "description": "a invalid day in date-time string",
-                "data": "1990-02-31T15:59:60.123-08:00",
+                "data": "1990-02-31T15:59:59.123-08:00",
                 "valid": false
             },
             {
                 "description": "an invalid offset in date-time string",
-                "data": "1990-12-31T15:59:60-24:00",
+                "data": "1990-12-31T15:59:59-24:00",
                 "valid": false
             },
             {

tests/draft4/optional/format/date-time.json

@@ -23,14 +23,24 @@
                 "data": "1990-12-31T15:59:50.123-08:00",
                 "valid": true
             },
+            {
+                "description": "a valid date-time with a leap second, UTC",
+                "data": "1998-12-31T23:59:60Z",
+                "valid": true
+            },
+            {
+                "description": "a valid date-time with a leap second, with minus offset",
+                "data": "1998-12-31T15:59:60.123-08:00",
+                "valid": true
+            },
             {
                 "description": "a invalid day in date-time string",
-                "data": "1990-02-31T15:59:60.123-08:00",
+                "data": "1990-02-31T15:59:59.123-08:00",
                 "valid": false
             },
             {
                 "description": "an invalid offset in date-time string",
-                "data": "1990-12-31T15:59:60-24:00",
+                "data": "1990-12-31T15:59:59-24:00",
                 "valid": false
             },
             {

tests/draft6/optional/format/date-time.json

@@ -23,14 +23,24 @@
                 "data": "1990-12-31T15:59:50.123-08:00",
                 "valid": true
             },
+            {
+                "description": "a valid date-time with a leap second, UTC",
+                "data": "1998-12-31T23:59:60Z",
+                "valid": true
+            },
+            {
+                "description": "a valid date-time with a leap second, with minus offset",
+                "data": "1998-12-31T15:59:60.123-08:00",
+                "valid": true
+            },
             {
                 "description": "a invalid day in date-time string",
-                "data": "1990-02-31T15:59:60.123-08:00",
+                "data": "1990-02-31T15:59:59.123-08:00",
                 "valid": false
             },
             {
                 "description": "an invalid offset in date-time string",
-                "data": "1990-12-31T15:59:60-24:00",
+                "data": "1990-12-31T15:59:59-24:00",
                 "valid": false
             },
             {

tests/draft7/optional/format/date-time.json

@@ -23,14 +23,24 @@
                 "data": "1990-12-31T15:59:50.123-08:00",
                 "valid": true
             },
+            {
+                "description": "a valid date-time with a leap second, UTC",
+                "data": "1998-12-31T23:59:60Z",
+                "valid": true
+            },
+            {
+                "description": "a valid date-time with a leap second, with minus offset",
+                "data": "1998-12-31T15:59:60.123-08:00",
+                "valid": true
+            },
             {
                 "description": "a invalid day in date-time string",
-                "data": "1990-02-31T15:59:60.123-08:00",
+                "data": "1990-02-31T15:59:59.123-08:00",
                 "valid": false
             },
             {
                 "description": "an invalid offset in date-time string",
-                "data": "1990-12-31T15:59:60-24:00",
+                "data": "1990-12-31T15:59:59-24:00",
                 "valid": false
             },
             {