Implement isProperFraction and add tests

Author: eyob-tech

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

@@ -1,21 +1,21 @@
 // Implement a function isProperFraction,
-// when given two numbers, a numerator and a denominator, it should return true if
+// when given two numbers, a numerator and a denominator, returns true if
 // the given numbers form a proper fraction, and false otherwise.
 
-// Assumption: The parameters are valid numbers (not NaN or Infinity).
+// Assumption: The parameters are valid numbers (not NaN or infinity).
 
-// Note: If you are unfamiliar with proper fractions, please look up its mathematical definition.
+// Note: If you are unfamiliar with proper fractions, please look it up.
 
 // Acceptance criteria:
-// After you have implemented the function, write tests to cover all the cases, and
+// After you have implemented the function, write tests to
 // execute the code to ensure all tests pass.
 
 function isProperFraction(numerator, denominator) {
-  // TODO: Implement this function
+  return Math.abs(numerator) < Math.abs(denominator);
 }
 
-// The line below allows us to load the isProperFraction function into tests in other files.
-// This will be useful in the "rewrite tests with jest" step.
+// The line below allows us to load the isProperFraction function into other files
+// This will be useful in the "rewrite tests with jest" step later
 module.exports = isProperFraction;
 
 // Here's our helper again
@@ -27,7 +27,11 @@ function assertEquals(actualOutput, targetOutput) {
 }
 
 // TODO: Write tests to cover all cases.
-// What combinations of numerators and denominators should you test?
+// What combinations of numerators and denominators should be tested?
 
 // Example: 1/2 is a proper fraction
 assertEquals(isProperFraction(1, 2), true);
+assertEquals(isProperFraction(2, 1), false);
+assertEquals(isProperFraction(-1, 2), true);
+assertEquals(isProperFraction(3, 3), false);
+

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

@@ -4,7 +4,24 @@ 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`, () => {
+// Special case: denominator is zero
+test('should return false when denominator is zero', () => {
   expect(isProperFraction(1, 0)).toEqual(false);
 });
+
+// Case: proper fractions
+test('should return true when the fraction is proper', () => {
+  expect(isProperFraction(1, 2)).toEqual(true);
+  expect(isProperFraction(-1, 2)).toEqual(true);
+});
+
+// Case: improper fractions
+test('should return false when the fraction is improper', () => {
+  expect(isProperFraction(2, 1)).toEqual(false);
+  expect(isProperFraction(3, 3)).toEqual(false);
+});
+
+// Case: numerator is zero
+test('should return true when numerator is zero', () => {
+  expect(isProperFraction(0, 5)).toEqual(true);
+});