Update tally.test.js

Author: joanne342

Sprint-2/implement/tally.test.js

@@ -20,15 +20,36 @@ const tally = require("./tally.js");
 // When passed an array of items
 // Then it should return an object containing the count for each unique item
 
+test("tally counts the frequency of each unique item", () => {
+  expect(tally(["a", "a", "b", "c"])).toEqual({
+    a: 2,
+    b: 1,
+    c: 1,
+  });
+});
+
 // Given an empty array
 // When passed to tally
 // Then it should return an empty object
-test.todo("tally on an empty array returns an empty object");
+
+test("tally on an empty array returns an empty object", () => {
+  expect(tally([])).toEqual({});
+});
 
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
 
+test("tally counts duplicate items correctly", () => {
+  expect(tally(["a", "a", "a"])).toEqual({
+    a: 3,
+  });
+});
+
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+
+test("tally throws an error when passed invalid input", () => {
+  expect(() => tally("a")).toThrow();
+});