added Jest tests

Author: Zadri415

Sprint-3/1-implement-and-rewrite-tests/implement/2-is-proper-fraction.js

@@ -12,6 +12,10 @@
 
 function isProperFraction(numerator, denominator) {
   // TODO: Implement this function
+  if (denominator === 0) {
+    return false;
+  }
+  return Math.abs(numerator) < Math.abs(denominator);
 }
 
 // The line below allows us to load the isProperFraction function into tests in other files.

Sprint-3/1-implement-and-rewrite-tests/rewrite-tests-with-jest/2-is-proper-fraction.test.js

@@ -5,6 +5,67 @@ const isProperFraction = require("../implement/2-is-proper-fraction");
 // TODO: Write tests in Jest syntax to cover all combinations of positives, negatives, zeros, and other categories.
 
 // Special case: numerator is zero
-test(`should return false when denominator is zero`, () => {
-  expect(isProperFraction(1, 0)).toEqual(false);
+// Tests using top-level `test()` calls
+
+test("denominator 0 returns false", () => {
+  expect(isProperFraction(1, 0)).toBe(false);
+});
+
+test("1/2 is a proper fraction", () => {
+  expect(isProperFraction(1, 2)).toBe(true);
+});
+
+test("2/4 is a proper fraction (non-reduced)", () => {
+  expect(isProperFraction(2, 4)).toBe(true);
+});
+
+test("5/4 is not a proper fraction", () => {
+  expect(isProperFraction(5, 4)).toBe(false);
 });
+
+test("2/2 is not a proper fraction (equal numerator and denominator)", () => {
+  expect(isProperFraction(2, 2)).toBe(false);
+});
+
+test("0/5 is proper", () => {
+  expect(isProperFraction(0, 5)).toBe(true);
+});
+
+test("0/-5 is proper (negative denominator)", () => {
+  expect(isProperFraction(0, -5)).toBe(true);
+});
+
+test("negative numerator handled via absolute value", () => {
+  expect(isProperFraction(-1, 2)).toBe(true);
+});
+
+test("negative denominator handled via absolute value", () => {
+  expect(isProperFraction(1, -2)).toBe(true);
+});
+
+test("both negative handled via absolute value", () => {
+  expect(isProperFraction(-3, -4)).toBe(true);
+});
+
+test("-3/3 is not proper (equal abs values)", () => {
+  expect(isProperFraction(-3, 3)).toBe(false);
+});
+
+test("decimal numerator works (0.5/1)", () => {
+  expect(isProperFraction(0.5, 1)).toBe(true);
+});
+
+test("decimal where numerator > denominator (1/0.9999)", () => {
+  expect(isProperFraction(1, 0.9999)).toBe(false);
+});
+
+// Optional: uncomment if implementation is updated to reject non-finite values
+// test('NaN inputs return false', () => {
+//   expect(isProperFraction(NaN, 1)).toBe(false);
+//   expect(isProperFraction(1, NaN)).toBe(false);
+// });
+
+// test('Infinity inputs return false', () => {
+//   expect(isProperFraction(Infinity, 1)).toBe(false);
+//   expect(isProperFraction(1, Infinity)).toBe(false);
+// });