Fix negative case

Author: jiachen1120

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 (accurateDividend.divideAndRemainder(accurateDivisor)[1].doubleValue() > 1e-12) {
+                if (Math.abs(accurateDividend.divideAndRemainder(accurateDivisor)[1].doubleValue()) > 1e-12) {
                     return Collections.singleton(buildValidationMessage(at, "" + divisor));
                 }
             }

src/test/resources/tests/multipleOf.json

@@ -80,8 +80,13 @@
             },
             {
                 "description": "9313.8 is a multiple of 0.01",
-                "data": 9313.888,
+                "data": -9313.8861,
                 "valid": false
+            },
+            {
+                "description": "9313.8 is a multiple of 0.01",
+                "data": -9313.8,
+                "valid": true
             }
         ]
     }