Add rules and test for required keyword, Draft 3 to 4 (#31)

Author: suprith-hub

rules/from-draft3/to-draft4/029-required-false-present-in-properties's-values.json

@@ -0,0 +1,11 @@
+{
+    "vocabulary": "core",
+    "condition": [
+        { "operation": "has-key", "path": [], "value": "properties" },
+        { "operation": "has-key", "path": [ "properties", {} ], "value": "required" },
+        { "operation": "equals", "path": [ "properties", {}, "required" ], "value": false }
+    ],
+    "transform": [
+        { "operation": "remove", "path": [ "properties", {}, "required" ] }
+    ]
+}

rules/from-draft3/to-draft4/030-required-is-present-in-outer-schema.json

@@ -0,0 +1,9 @@
+{
+    "vocabulary": "core",
+    "condition": [
+        { "operation": "has-key", "path": [], "value": "required" }
+    ],
+    "transform": [
+        { "operation": "replace", "path": [ "required" ], "value": [] }
+    ]
+}

rules/from-draft3/to-draft4/031-required-is-absent-and-required-true-in-properties.json

@@ -0,0 +1,12 @@
+{
+    "vocabulary": "core",
+    "condition": [
+        { "operation": "not-has-key", "path": [], "value": "required" },
+        { "operation": "has-key", "path": [], "value": "properties" },
+        { "operation": "has-key", "path": [ "properties", {} ], "value": "required" },
+        { "operation": "equals", "path": [ "properties", {}, "required" ], "value": true }
+    ],
+    "transform": [
+        { "operation": "add", "path": [ "required" ], "value": [] }
+    ]
+}

rules/from-draft3/to-draft4/032-required-true-present-in-properties's-values.json

@@ -0,0 +1,12 @@
+{
+    "vocabulary": "core",
+    "condition": [
+        { "operation": "has-key", "path": [], "value": "properties" },
+        { "operation": "has-key", "path": [ "properties", {} ], "value": "required" },
+        { "operation": "equals", "path": [ "properties", {}, "required" ], "value": true }
+    ],
+    "transform": [
+        { "operation": "append-property", "to": [ "required" ], "from": [ "properties", {} ] },
+        { "operation": "remove", "path": [ "properties", {}, "required" ] }
+    ]
+}

rules/from-draft3/to-draft4/033-empty-required-array-in-outer-schema.json

@@ -0,0 +1,10 @@
+{
+    "vocabulary": "core",
+    "condition": [
+        { "operation": "has-key", "path": [], "value": "required" },
+        { "operation": "size-equals", "path": [ "required" ], "value": 0 }
+    ],
+    "transform": [
+        { "operation": "remove", "path": [ "required" ] }
+    ]
+}

test/from-draft3/to-draft4/required.json

@@ -0,0 +1,65 @@
+[
+    {
+        "title": "`required` is true in properties/{something} and required absent in outer schema",
+        "from": {
+            "properties": {
+                "foo": { "required": true },
+                "bar": { 
+                    "type": "string",
+                    "required": true 
+                }
+            }
+        },
+        "to": {
+            "properties": {
+                "foo": {},
+                "bar": { 
+                    "type": "string"
+                }
+            },
+            "required": [ "foo", "bar" ]
+        }
+    },
+    {
+        "title": "`required` is true in properties/{something} and required boolean in outer schema",
+        "from": {
+            "properties": {
+                "foo": { "required": true },
+                "bar": { 
+                    "type": "string",
+                    "required": true 
+                }
+            },
+            "required": false
+        },
+        "to": {
+            "properties": {
+                "foo": {},
+                "bar": { 
+                    "type": "string"
+                }
+            },
+            "required": [ "foo", "bar" ]
+        }
+    },
+    {
+        "title": "`required` has value false present in properties children",
+        "from": {
+            "properties": {
+                "foo": { "required": false }
+            }
+        },
+        "to": {
+            "properties": {
+                "foo": {}
+            }
+        }
+    },
+    {
+        "title": "`required` is an empty array in outer schema",
+        "from": {
+            "required": []
+        },
+        "to": {}
+    }
+]