test: enhance isProperFraction tests for edge cases and clarify descriptions

Author: tomdu3

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

@@ -8,23 +8,30 @@ const isProperFraction = require("../implement/2-is-proper-fraction");
 test(`should return false when denominator is zero`, () => {
   expect(isProperFraction(1, 0)).toEqual(false);
   expect(isProperFraction(2, 0)).toEqual(false);
+  expect(isProperFraction(-4, 0)).toEqual(false);
+  
 
 });
 
 // Case 2: Denominator is greater than numerator
-test(`should return true when denominator is greater than numerator`, () => {
+test(`should return true when absolute value of denominator is greater than absolute value of numerator`, () => {
   expect(isProperFraction(1, 2)).toEqual(true);
   expect(isProperFraction(2, 4)).toEqual(true);
   expect(isProperFraction(3, 6)).toEqual(true);
   expect(isProperFraction(4, 8)).toEqual(true);
   expect(isProperFraction(5, 10)).toEqual(true);
+  expect(isProperFraction(-1, 2)).toEqual(true);
+  expect(isProperFraction(2, -4)).toEqual(true);
+  expect(isProperFraction(-3, -6)).toEqual(true);
+  expect(isProperFraction(0, 5)).toEqual(true);
 });
 
 // Case 3: Denominator is less than numerator
-test(`should return false when denominator is less than numerator`, () => {
+test(`should return false when absolute value of denominator is less than absolute value of numerator`, () => {
   expect(isProperFraction(2, 1)).toEqual(false);
   expect(isProperFraction(4, 2)).toEqual(false);
   expect(isProperFraction(6, 3)).toEqual(false);
   expect(isProperFraction(8, 4)).toEqual(false);
   expect(isProperFraction(10, 5)).toEqual(false);
+  expect(isProperFraction(-5, 4)).toEqual(false);
 });