Add tests for isProperFraction function and implement getCardValue function with rank handling

Author: MohammedNaru

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

@@ -1,3 +1,5 @@
+// Sprint-3/1-implement-and-rewrite-tests/rewrite-tests-with-jest/2-is-proper-fraction.test.js
+
 // This statement loads the isProperFraction function you wrote in the implement directory.
 // We will use the same function, but write tests for it using Jest in this file.
 const isProperFraction = require("../implement/2-is-proper-fraction");
@@ -26,3 +28,67 @@ test("should return true for a negative proper fraction (|numerator| < denominat
 test("should return false when numerator equals denominator", () => {
   expect(isProperFraction(3, 3)).toEqual(false);
 });
+
+// When the numerator is negative but |numerator| >= denominator,
+// Then the function should return false
+test("should return false for a negative improper fraction (|numerator| >= denominator)", () => {
+  expect(isProperFraction(-8, 7)).toEqual(false);
+});
+
+// When the numerator is zero,
+// Then the function should return true
+test("should return true when numerator is zero", () => {
+  expect(isProperFraction(0, 5)).toEqual(true);
+});
+
+// When the denominator is zero,
+// Then the function should throw an error
+test("should throw an error when denominator is zero", () => {
+  expect(() => {
+    isProperFraction(3, 0);
+  }).toThrow("Denominator cannot be zero");
+});
+
+// When the numerator or denominator is not an integer,
+// Then the function should throw an error
+test("should throw an error when numerator or denominator is not an integer", () => {
+  expect(() => {
+    isProperFraction(2.5, 4);
+  }).toThrow("Numerator and denominator must be integers");
+
+  expect(() => {
+    isProperFraction(3, "5");
+  }).toThrow("Numerator and denominator must be integers");
+});
+
+
+// Sprint-3/1-implement-and-rewrite-tests/implement/3-get-card-value.js
+// This function takes a card string (e.g., "A♠", "10♥", "K♦") and returns its value in a game of cards.
+function getCardValue(card) {
+  // Extract rank by removing suit symbol (last character)
+  const rank = card.slice(0, -1);
+
+  // Map face cards to values
+  const faceValues = {
+    J: 10,
+    Q: 10,
+    K: 10,
+    A: 11,
+  };
+
+  // Return mapped value if rank is a face card
+  if (faceValues[rank]) {
+    return faceValues[rank];
+  }
+
+  // Convert to number and validate numeric cards (2–10)
+  const numericValue = Number(rank);
+  if (!isNaN(numericValue) && numericValue >= 2 && numericValue <= 10) {
+    return numericValue;
+  }
+
+  // Invalid card
+  throw new Error("Invalid card rank");
+}
+
+module.exports = getCardValue;