Improve accuracy of rounding with multipleOf

Author: seamusv

src/main/java/com/networknt/schema/MultipleOfValidator.java

@@ -48,7 +48,7 @@ public Set<ValidationMessage> validate(JsonNode node, JsonNode rootNode, String
                 // convert to BigDecimal since double type is not accurate enough to do the division and multiple
                 BigDecimal accurateDividend = new BigDecimal(String.valueOf(nodeValue));
                 BigDecimal accurateDivisor = new BigDecimal(String.valueOf(divisor));
-                if (Math.abs(accurateDividend.divideAndRemainder(accurateDivisor)[1].doubleValue()) > 1e-12) {
+                if ((accurateDividend.divideAndRemainder(accurateDivisor)[1].abs().compareTo(BigDecimal.ZERO) > 0)) {
                     return Collections.singleton(buildValidationMessage(at, "" + divisor));
                 }
             }

src/test/resources/draft4/multipleOf.json

@@ -89,5 +89,31 @@
                 "valid": true
             }
         ]
+    },
+    {
+        "description": "by deep rounding",
+        "schema": {"multipleOf": 0.25},
+        "tests": [
+            {
+                "description": "8.75 is multiple of 0.25",
+                "data": 8.75,
+                "valid": true
+            },
+            {
+                "description": "8.750000000001 is not multiple of 0.25",
+                "data": 8.750000000001,
+                "valid": false
+            },
+            {
+                "description": "8.7500000000001 is not multiple of 0.25",
+                "data": 8.7500000000001,
+                "valid": false
+            },
+            {
+                "description": "8.75000000000001 is not multiple of 0.25",
+                "data": 8.75000000000001,
+                "valid": false
+            }
+        ]
     }
 ]

src/test/resources/draft6/multipleOf.json

@@ -56,5 +56,31 @@
                 "valid": false
             }
         ]
+    },
+    {
+        "description": "by deep rounding",
+        "schema": {"multipleOf": 0.25},
+        "tests": [
+            {
+                "description": "8.75 is multiple of 0.25",
+                "data": 8.75,
+                "valid": true
+            },
+            {
+                "description": "8.750000000001 is not multiple of 0.25",
+                "data": 8.750000000001,
+                "valid": false
+            },
+            {
+                "description": "8.7500000000001 is not multiple of 0.25",
+                "data": 8.7500000000001,
+                "valid": false
+            },
+            {
+                "description": "8.75000000000001 is not multiple of 0.25",
+                "data": 8.75000000000001,
+                "valid": false
+            }
+        ]
     }
 ]

src/test/resources/draft7/multipleOf.json

@@ -56,5 +56,31 @@
                 "valid": false
             }
         ]
+    },
+    {
+        "description": "by deep rounding",
+        "schema": {"multipleOf": 0.25},
+        "tests": [
+            {
+                "description": "8.75 is multiple of 0.25",
+                "data": 8.75,
+                "valid": true
+            },
+            {
+                "description": "8.750000000001 is not multiple of 0.25",
+                "data": 8.750000000001,
+                "valid": false
+            },
+            {
+                "description": "8.7500000000001 is not multiple of 0.25",
+                "data": 8.7500000000001,
+                "valid": false
+            },
+            {
+                "description": "8.75000000000001 is not multiple of 0.25",
+                "data": 8.75000000000001,
+                "valid": false
+            }
+        ]
     }
 ]