test: write test cases for HashTable class

Author: francislagares

src/hash-table/HashTable.ts

@@ -1,8 +1,8 @@
 export class HashTable {
-  protected size: number;
-  private data;
+  public size: number;
+  public data;
 
-  constructor(size: number) {
+  constructor(size?: number) {
     this.size = size;
     this.data = new Array(size);
   }
@@ -37,8 +37,8 @@ export class HashTable {
     return undefined;
   }
 
-  public keys() {
-    const keysArray = [];
+  public keys(): string[] {
+    const keysArray: string[] = [];
     for (let i = 0; i < this.data.length; i++) {
       if (this.data[i]) {
         keysArray.push(this.data[i][0][0]);

src/hash-table/__tests__/HashTable.test.ts

@@ -0,0 +1,20 @@
+import { HashTable } from '../HashTable';
+
+describe('Hash Table Class Implementation', () => {
+  test('create a hash table of a given size', () => {
+    const hashTable = new HashTable(65);
+    expect(hashTable.size).toBe(65);
+  });
+
+  test('create new empty hash table', () => {
+    const hashTable = new HashTable();
+    expect(hashTable.size).toBe(undefined);
+  });
+
+  test('set data to hash table', () => {
+    const hashTable = new HashTable();
+    hashTable.set('Users', 150);
+
+    expect(hashTable.get('Users')).toBe(150);
+  });
+});