Issue #102 Fixed Number.toString method

Src/IronJS/Native.Number.fs

@@ -62,18 +62,22 @@ module internal Number =
         | _ ->
           let digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
           let mutable result = ""
+          let mutable isNegative = false
           let mutable number = bigint (int64 number)
           if number < bigint.Zero then
-            result <- "-"
+            isNegative <- true
             number <- -number
           if number = bigint.Zero then "0"
           else
             let radix = bigint radix
             while number > bigint.Zero do
               let digit = int (number % radix)
               number <- number / radix
-              result <- result + digits.[digit].ToString()
-            result
+              result <- digits.[digit].ToString() + result
+            if isNegative then
+              "-" + result
+            else
+              result
 
     ///
     let private toLocaleString (f:FO) (this:CO) = 

Src/Tests/Sputnik/sputnik-v1/tests/Conformance/08_Types/8.5_The_Number_Type/S8.5_A15.js

@@ -0,0 +1,20 @@
+/**
+ * @name: S8.5_A8;
+ * @section: 8.5, 7.8.3;
+ * @assertion: Number.toString(16) should return valid number
+ * @description: https://github.com/fholm/IronJS/issues/102
+*/
+
+var n = 9999;
+var n16 = n.toString(16)
+
+if (n16 !== "270F") {
+    $ERROR("#1: Number.toString(16) should return valid number. Expected 270F, but have " + n16);
+}
+
+n = -9999;
+n16 = n.toString(16)
+
+if (n16 !== "-270F") {
+    $ERROR("#2: Number.toString(16) should return valid number. Expected -270F, but have " + n16);
+}

Src/Tests/UnitTests/Sputnik/Conformance/Types/TheNumberTypeTests.cs

@@ -165,5 +165,15 @@ public void GloballyDefinedVariableNaNHasNotBeenAlteredByProgramExecution(string
         {
             RunFile(file);
         }
+
+        [Test]
+        [Category("Sputnik Conformance")]
+        [Category("ECMA 7.8.3")]
+        [Category("ECMA 8.5")]
+        [TestCase("S8.5_A15.js", Description = "Number.toString(16) should return valid number")]
+        public void ToStringBase16IsCorrect(string file)
+        {
+            RunFile(file);
+        }
     }
 }