sum function updated and float coverage added to test cases

Author: mervereis

Sprint-1/implement/sum.js

@@ -1,10 +1,5 @@
 function sum(elements) {
-  const numbers = elements.filter((el) => typeof el === "number");
-
-  if (numbers.length === 0) return 0;
-
-  if (numbers.length === 1) return numbers[0];
-
+  const numbers = elements.filter((el) => Number.isFinite(el));
   const sumNumbers = numbers.reduce((a, b) => a + b, 0);
   return sumNumbers;
 }

Sprint-1/implement/sum.test.js

@@ -26,7 +26,7 @@ describe("sum", () => {
   // When passed to the sum function
   // Then it should return the correct total sum
   test("sums decimal numbers correctly", () => {
-    expect(sum([1.5, 2.5, 3.5])).toBe(7.5);
+    expect(sum([1.5, 2.5, 3.5])).toBeCloseTo(7.5, 5);
   });
 
   // Given an array containing non-number values
@@ -42,4 +42,27 @@ describe("sum", () => {
   test("returns 0 when array contains only non-number values", () => {
     expect(sum(["a", "b", "c"])).toBe(0);
   });
+
+  test("handles floating point precision issues", () => {
+    expect(sum([1.2, 0.6, 0.005])).toBeCloseTo(1.805, 5);
+  });
+
+  test("returns consistent result regardless of order", () => {
+    const a = sum([1.2, 0.6, 0.005]);
+    const b = sum([0.005, 0.6, 1.2]);
+
+    expect(a).toBeCloseTo(b, 10);
+  });
+
+  test("ignores NaN and Infinity values", () => {
+    expect(sum([10, NaN, 20, Infinity, -Infinity])).toBe(30);
+  });
+
+  test("returns 0 when only NaN and Infinity are present", () => {
+    expect(sum([NaN, Infinity, -Infinity])).toBe(0);
+  });
+
+  test("does not treat numeric strings as numbers", () => {
+    expect(sum([10, "20", 30])).toBe(40);
+  });
 });