Add comprehensive Jest tests for isProperFraction function covering various cases

Author: Alex-Os-Dev-Lab

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

@@ -8,3 +8,60 @@ const isProperFraction = require("../implement/2-is-proper-fraction");
 test(`should return false when denominator is zero`, () => {
   expect(isProperFraction(1, 0)).toEqual(false);
 });
+
+test(`should return true when numerator is zero and denominator is non-zero`, () => {
+  expect(isProperFraction(0, 5)).toEqual(true);
+});
+
+// Proper fractions with positive numbers
+test(`should return true for proper fractions with positive numerator and denominator`, () => {
+  expect(isProperFraction(1, 2)).toEqual(true);
+  expect(isProperFraction(3, 4)).toEqual(true);
+});
+
+// Improper fractions with positive numbers
+test(`should return false for improper fractions with positive numerator and denominator`, () => {
+  expect(isProperFraction(2, 1)).toEqual(false);
+  expect(isProperFraction(5, 3)).toEqual(false);
+});
+
+// Proper fractions with negative numbers
+test(`should return true for proper fractions with negative numerator and positive denominator`, () => {
+  expect(isProperFraction(-1, 2)).toEqual(true);
+  expect(isProperFraction(-3, 4)).toEqual(true);
+});
+
+test(`should return true for proper fractions with positive numerator and negative denominator`, () => {
+  expect(isProperFraction(1, -2)).toEqual(true);
+  expect(isProperFraction(3, -4)).toEqual(true);
+});
+
+// Improper fractions with negative numbers
+test(`should return false for improper fractions with negative numerator and positive denominator`, () => {
+  expect(isProperFraction(-2, 1)).toEqual(false);
+  expect(isProperFraction(-5, 3)).toEqual(false);
+});
+test(`should return false for improper fractions with positive numerator and negative denominator`, () => {
+  expect(isProperFraction(2, -1)).toEqual(false);
+  expect(isProperFraction(5, -3)).toEqual(false);
+});
+
+// Special case: both numerator and denominator are zero
+test(`should return false when both numerator and denominator are zero`, () => {
+  expect(isProperFraction(0, 0)).toEqual(false);
+});
+
+// Numerator equals denominator
+test("should return false when numerator equals denominator", () => {
+  expect(isProperFraction(5, 5)).toBe(false);
+  expect(isProperFraction(-5, -5)).toBe(false);
+});
+
+// Both numerator and denominator are negative
+test("should return true for proper fractions with two negative numbers", () => {
+  expect(isProperFraction(-1, -3)).toBe(true);
+});
+
+test("should return false for improper fractions with two negative numbers", () => {
+  expect(isProperFraction(-10, -2)).toBe(false);
+});