+ Adding unit tests and fix for empty value

src/core/operations/BasicArithmetic.mjs

@@ -4,6 +4,7 @@
  * @license Apache-2.0
  */
 
+import BigNumber from "bignumber.js";
 import Operation from "../Operation.mjs";
 
 /**
@@ -31,14 +32,20 @@ class BasicArithmetic extends Operation {
      * @returns {number}
      */
     run(input, args) {
+        if (input.length >= 1) {
             if (parseInt(input, 10).toString().length === input.length) {
-            return parseInt(input, 10);
+                const val = parseInt(input, 10);
+                return BigNumber.isBigNumber(val) ? val : new BigNumber(NaN);
             } else {
                 return (input.replace(/\s/g, "").match(/[+-]?([0-9.]+)/g) || [])
                     .reduce(function (sum, value) {
-                    return parseFloat(sum) + parseFloat(value);
+                        const val = parseFloat(sum) + parseFloat(value);
+                        return BigNumber.isBigNumber(val) ? val : new BigNumber(NaN);
                     });
             }
+        } else {
+            return new BigNumber(NaN);
+        }
     }
 
 }

tests/operations/tests/BasicArithmetic.mjs

@@ -0,0 +1,68 @@
+/**
+ * @author scottdermott [scottdermott@outlook.com]
+ * @copyright Crown Copyright 2021
+ * @license Apache-2.0
+ */
+
+/**
+ * Basic Arithmetic Tests
+ */
+import TestRegister from "../../lib/TestRegister.mjs";
+
+TestRegister.addTests([
+    {
+        name: "BasicArithmetic: nothing",
+        input: "",
+        expectedOutput: "",
+        recipeConfig: [
+            {
+                op: "BasicArithmetic",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "BasicArithmetic: Addition",
+        input: "1+2+3+4+5+6+7+8+9+0",
+        expectedOutput: 45,
+        recipeConfig: [
+            {
+                op: "BasicArithmetic",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "BasicArithmetic: Subtraction",
+        input: "100-9-8-7-6-5-4-3-2-1-0",
+        expectedOutput: 55,
+        recipeConfig: [
+            {
+                op: "BasicArithmetic",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "BasicArithmetic: Add + Sub",
+        input: "1+2+3+4+5+6+7+8+9-9-8-7-6-5-4-3-2-1",
+        expectedOutput: 0,
+        recipeConfig: [
+            {
+                op: "BasicArithmetic",
+                args: [],
+            },
+        ],
+    },
+    {
+        name: "BasicArithmetic: Large number",
+        input: "999+999+999+999+999+999+999+999+999+999+999+999+999+999+999+999+999+999+999+999+999+999+999",
+        expectedOutput: 22977,
+        recipeConfig: [
+            {
+                op: "BasicArithmetic",
+                args: [],
+            },
+        ],
+    },
+]);